Genomic landscape of diploid and aneuploid microsatellite stable early onset colorectal cancer

Although colorectal cancer (CRC) remains the second leading cause of cancer-related death in the United States, the overall incidence and mortality from the disease have declined in recent decades. In contrast, there has been a steady increase in the incidence of CRC in individuals under 50 years of age. Hereditary syndromes contribute disproportionately to early onset CRC (EOCRC). These include microsatellite instability high (MSI+) tumors arising in patients with Lynch Syndrome. However, most EOCRCs are not associated with familial syndromes or MSI+ genotypes. Comprehensive genomic profiling has provided the basis of improved more personalized treatments for older CRC patients. However, less is known about the basis of sporadic EOCRC. To define the genomic landscape of EOCRC we used DNA content flow sorting to isolate diploid and aneuploid tumor fractions from 21 non-hereditary cases. We then generated whole exome mutational profiles for each case and whole genome copy number, telomere length, and EGFR immunohistochemistry (IHC) analyses on subsets of samples. These results discriminate the molecular features of diploid and aneuploid EOCRC and provide a basis for larger population-based studies and the development of effective strategies to monitor and treat this emerging disease.

Gastrointestinal histoplasmosis with small intestinal perforation: 20-year experience

Postmortem studies show gastrointestinal tract involvement in as many as 70% of patients affected by disseminated histoplasmosis. Although gastrointestinal involvement is common in disseminated disease, the presentation of small intestinal perforation is exceedingly rare with few reported cases in the literature. Herein we present our institutional case series. The aim of the study is to describe small intestinal perforation in gastrointestinal histoplasmosis with attention to management and outcomes. This is a retrospective single-institution review of patients ≥ 18 years of age treated for small intestinal perforation due to gastrointestinal histoplasmosis. A prospectively maintained institutional database was searched from 2002 to 2022. Data obtained included demographics, comorbidities, treatment course, and outcomes. Five patients with a mean age of 54 years (range 25-72) were identified. Pertinent underlying comorbid conditions included Crohn's disease, psoriatic arthritis, rheumatoid arthritis, and solid organ transplantation. All patients were on chronic immunosuppressive medication(s) with the most common being tumor necrosis factors alpha inhibitors and corticosteroids. Four had a clinical diagnosis of perforation based on physical examination and imaging. All patients underwent segmental resection(s) of the small intestine and received medical treatment with intravenous amphotericin B and eventual transition to an oral antifungal. No patients experienced complications related to surgery. The limitations of the study include nonrandomized retrospective review, single-institution experience, and small patient sample size. Although rare, histoplasmosis should be considered in the differential of patients on chronic immunosuppressive therapy who present with gastrointestinal symptoms concerning perforation, especially from endemic areas. Small intestinal perforation due to gastrointestinal histoplasmosis can be successfully treated with resection and antifungal therapy.

Syngeneic murine models with distinct immune microenvironments represent subsets of human intrahepatic cholangiocarcinoma

BACKGROUND & AIMS

Cholangiocarcinoma (CCA) is a poorly immunogenic malignancy associated with limited survival. Syngeneic immunocompetent mouse models of CCA are an essential tool to elucidate the tumor immune microenvironment (TIME), understand mechanisms of tumor immune evasion, and test novel immunotherapeutic strategies. The scope of this study was to develop and characterize immunocompetent CCA models with distinct genetic drivers, and correlate tumor genomics, immunobiology, and therapeutic response.

METHODS

A multifaceted approach including scRNA-seq, CITE-seq, whole exome and bulk RNA sequencing was employed. FDA-approved PD-1/PD-L1 antibodies were tested in humanized PD-1/PD-L1 mice (HuPD-H1).

RESULTS

A genetic mouse model of intrahepatic CCA (iCCA) driven by intrabiliary transduction of Fbxw7ΔF/Akt that mimics human iCCA was generated. From the Fbxw7ΔF/Akt tumors, a murine cell line (FAC) and syngeneic model with genetic and phenotypic characteristics of human iCCA were developed. Established SB1 (YAPS127A/Akt) and KPPC (KrasG12Dp53L/L) models were compared to the FAC model. Although the models had transcriptomic similarities, they had substantial differences as well. Mutation patterns of FAC, SB1, and KPPC cells matched different mutational signatures in Western and Japanese CCA patient cohorts. KPPC tumors had a high tumor mutation burden. FAC tumors had a T cell-infiltrated TIME, while SB1 tumors had a preponderance of suppressive myeloid cells. FAC, SB1, and KPPC tumors matched different immune signatures in human iCCA cohorts. Moreover, FAC, SB1, and KPPC tumor-bearing HuPD-H1 mice displayed differential responses to nivolumab or durvalumab.

CONCLUSIONS

Syngeneic iCCA models display a correlation between tumor genotype and TIME phenotype, with differential responses to FDA-approved immunotherapies. This study underscores the importance of leveraging multiple preclinical models to understand responses to immunotherapy in different genetic subsets of human CCA.

IMPACT AND IMPLICATIONS

Understanding the relationship between tumor genotype and the phenotype of the immune microenvironment is an unmet need in cholangiocarcinoma (CCA). Herein, we use syngeneic murine models of intrahepatic CCA with different genetic drivers to demonstrate a correlation between tumor genotype and immune microenvironment phenotype in murine models, which is associated with differential responses to FDA-approved immunotherapies. This information will help guide other preclinical studies. Additionally, it emphasizes that immune checkpoint inhibition in patients with CCA is not a "one-size-fits-all" approach. Our observations suggest that, as for targeted therapies, patients should be stratified and selected for treatment according to their tumor genetics.

Improved risk stratification scheme for mismatch repair proficient stage II colorectal cancers using the digital pathology biomarker QuantCRC

PURPOSE

There is a need to improve current risk stratification of stage II colorectal cancer (CRC) to better inform risk of recurrence and guide adjuvant chemotherapy. We sought to examine whether integration of QuantCRC, a digital pathology biomarker utilizing hematoxylin and eosin-stained slides, provides improved risk stratification over current American Society of Clinical Oncology (ASCO) guidelines.

EXPERIMENTAL DESIGN

ASCO and QuantCRC-integrated schemes were applied to a cohort of 398 mismatch repair proficient (MMRP) stage II CRCs from three large academic medical centers. The ASCO stage II scheme was taken from recent guidelines. The QuantCRC-integrated scheme utilized pT3 vs. pT4 and a QuantCRC-derived risk classification. Evaluation of recurrence free survival (RFS) according to these risk schemes was compared using the log-rank test and hazard ratios.

RESULTS

Integration of QuantCRC provides improved risk stratification compared to the ASCO scheme for stage II MMRP CRCs. The QuantCRC-integrated scheme placed more stage II tumors in the low-risk group compared to the ASCO scheme (62.5% vs. 42.2%) without compromising excellent 3-year RFS. The QuantCRC-integrated scheme provided larger hazard ratios (HR) for both intermediate-risk (2.27, 95%CI 1.32-3.91, P=0.003) and high-risk (3.27, 95%CI 1.42-7.55, P=0.006) groups compared to ASCO intermediate-risk (1.58, 95%CI 0.87-2.87, P=0.1) and high-risk (2.24, 95%CI 1.09-4.62, P=0.03) groups. The QuantCRC-integrated risk groups remained prognostic in the subgroup of patients that did not receive any adjuvant chemotherapy.

CONCLUSIONS

Incorporation of QuantCRC into risk stratification provides a powerful predictor of RFS that has potential to guide subsequent treatment and surveillance for stage II MMRP CRCs.

NIPBL::NACC1 Fusion Hepatic Carcinoma

Several reports describing a rare primary liver tumor with histologic features reminiscent of follicular thyroid neoplasms have been published under a variety of descriptive terms including thyroid-like, solid tubulocystic, and cholangioblastic cholangiocarcinoma. Although these tumors are considered to represent histologic variants, they lack classic features of cholangiocarcinoma and have unique characteristics, namely immunoreactivity for inhibin and NIPBL::NACC1 fusions. The purpose of this study is to present clinicopathologic and molecular data for a large series of these tumors to better understand their pathogenesis. We identified 11 hepatic tumors with these features. Immunohistochemical and NACC1 and NIPBL fluorescence in situ hybridization assays were performed on all cases. Four cases had available material for whole-genome sequencing (WGS) analysis. Most patients were adult women (mean age: 42 y) who presented with abdominal pain and large hepatic masses (mean size: 14 cm). Ten patients had no known liver disease. Of the patients with follow-up information, 3/9 (33%) pursued aggressive behavior. All tumors were composed of bland cuboidal cells with follicular and solid/trabecular growth patterns in various combinations, were immunoreactive for inhibin, showed albumin mRNA by in situ hybridization, and harbored the NIPBL::NACC1 fusion by fluorescence in situ hybridization. WGS corroborated the presence of the fusion in all 4 tested cases, high tumor mutational burden in 2 cases, and over 30 structural variants per case in 3 sequenced tumors. The cases lacked mutations typical of conventional intrahepatic cholangiocarcinoma. In this report, we describe the largest series of primary inhibin-positive hepatic neoplasms harboring a NIPBL::NACC1 fusion and the first WGS analysis of these tumors. We propose to name this neoplasm NIPBL:NACC1 fusion hepatic carcinoma.

CT findings in idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) and comparison to other colitides

PURPOSE

The purpose of this study is to determine computed tomography (CT) findings that aid in differentiating idiopathic myointimal hyperplasia of mesenteric veins (IMHMV) from other colitides.

METHODS

Retrospective review of histiologic proven cases of IMHMV (n = 12) with contrast enhanced CT (n = 11) and/or computed tomography angiography (CTA) (n = 9) exams. Control groups comprised of CT of infectious colitis (n = 13), CT of inflammatory bowel disease (IBD) (n = 12), and CTA of other colitides (n = 13). CT exams reviewed by 2 blinded gastrointestinal radiologists for maximum bowel wall thickness, enhancement pattern, decreased bowel wall enhancement, submucosal attenuation value, presence and location of IMV occlusion, peripheral mesenteric venous occlusion, dilated pericolonic veins, subjective IMA dilation, maximum IMA diameter, maximum peripheral IMA branch diameter, ascites, and mesenteric edema. Presence of early filling veins was an additional finding evaluated on CTA exams.

RESULTS

Statistically significant CT findings of IMHMV compared to control groups included greater maximum bowel wall thickness, decreased bowel enhancement, IMV occlusion, and peripheral mesenteric venous occlusion (p < 0.05). Dilated pericolonic veins were seen more frequently in IMHMV compared to the infectious colitis group (64% versus 15%, p = 0.02). Additional statistically significant finding on CTA included early filling veins in IMHMV compared to the CTA control group (100% versus 46%, p = 0.008).

CONCLUSION

IMHMV is a rare chronic non-thrombotic ischemia predominantly involving the rectosigmoid colon. CT features that may aid in differentiating IMHMV from other causes of left-sided colitis include marked bowel wall thickening with decreased enhancement, IMV and peripheral mesenteric venous occlusion or tapering, and early filling of dilated veins on CTA.

IDH1-mutated Crohn's disease-associated small bowel adenocarcinomas: Distinctive pathological features and association with MGMT methylation and serrated-type dysplasia

AIMS

Patients with Crohn's disease (CrD) have an elevated risk for the development of small bowel adenocarcinomas (SBAs). Actionable isocitrate dehydrogenase 1 (IDH1) mutations have been reported to be more frequent in CrD-SBAs than in sporadic SBAs. The present study aimed to investigate the clinicopathological and immunophenotypical features, as well as methylation profiles, of IDH1-mutated CrD-SBAs.

METHODS AND RESULTS

An international multicentre series of surgically resected CrD-SBAs was tested for IDH1 mutation. Clinicopathological features, immunophenotypical marker expression and O6-methylguanine-DNA methyltransferase (MGMT) and long interspersed nuclear element-1 (LINE-1) methylation were compared between IDH1-mutated and IDH1 wild-type CrD-SBAs. Ten (20%) of the 49 CrD-SBAs examined harboured an IDH1 mutation and all the mutated cancers harboured the R132C variant. Compared to IDH1 wild-type cases, IDH1-mutated CrD-SBAs showed significantly lower rates of cytokeratin 7 expression (P = 0.005) and higher rates of p53 overexpression (P = 0.012) and MGMT methylation (P = 0.012). All three dysplastic growths associated with IDH1-mutated SBAs harboured the same IDH1 variant (R132C) of the corresponding invasive cancer, and all were of non-conventional subtype (two serrated dysplastic lesions and one goblet cell-deficient dysplasia). In particular, non-conventional serrated dysplasia was significantly associated with IDH1-mutated CrD-SBAs (P = 0.029). No significant cancer-specific survival difference between IDH1-mutated CrD-SBA patients and IDH1 wild-type CrD-SBA patients was found (hazard ratio = 0.55, 95% confidence interval = 0.16-1.89; P = 0.313).

CONCLUSIONS

IDH1-mutated CrD-SBAs, which represent approximately one-fifth of total cases, are characterised by distinctive immunophenotypical features and methylation profiles, with potential therapeutic implications. Moreover, IDH1-mutated non-conventional, serrated dysplasia is likely to represent a precursor lesion to such CrD-SBAs.

A case-control autopsy series of liver pathology associated with novel coronavirus disease (COVID-19)

BACKGROUND

Although severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) responsible for coronavirus disease 2019 (COVID-19) is most well-known for causing pulmonary injury, a significant proportion of patients experience hepatic dysfunction. The mechanism by which SARS-CoV2 causes liver injury is not fully understood. The goal of this study was to describe the hepatic pathology in a large cohort of deceased patients with COVID-19 as compared to a control group of deceased patients without COVID-19.

METHODS

Consented autopsy cases at two institutions were searched for documentation of COVID-19 as a contributing cause of death. A group of consecutive consented autopsy cases during the same period, negative for SARS-CoV-2 infection, was used as a control group. The autopsy report and electronic medical records were reviewed for relevant clinicopathologic information. H&E-stained liver sections from both groups were examined for pertinent histologic features. Select cases underwent immunohistochemical staining for CD 68 and ACE2 and droplet digital polymerase chain reaction (ddPCR) assay for evaluation of SARS-CoV2 RNA.

RESULTS

48 COVID-19 positive patients (median age 73, M:F 3:1) and 40 COVID-19 negative control patients (median age 67.5, M:F 1.4:1) were included in the study. The COVID-19 positive group was significantly older and had a lower rate of alcoholism and malignancy, but there was no difference in other comorbidities. The COVID-19 positive group was more likely to have received steroids (75.6 % vs. 36.1 %, p < 0.001). Hepatic vascular changes were seen in a minority (10.6 %) of COVID-19 positive cases. When all patients were included, there were no significant histopathologic differences between groups, but when patients with chronic alcoholism were excluded, the COVID-19 positive group was significantly more likely to have steatosis (80.9 % vs. 50.0 %, p = 0.004) and lobular inflammation (45.7 % vs. 20.7 %, p = 0.03). Testing for viral RNA by ddPCR identified 2 of the 18 (11.1 %) COVID-19 positive cases to have SARS-CoV-2 RNA detected within the liver FFPE tissue.

CONCLUSIONS

The most significant findings in the liver of COVID-19 positive patients were mild lobular inflammation and steatosis. The high rate of steroid therapy in this population may be a possible source of steatosis. Hepatic vascular alterations were only identified in a minority of patients and did not appear to play a predominant role in COVID-19 mediated hepatic injury. Low incidence of SARS-CoV-2 RNA positivity in liver tissue in our cohort suggests hepatic injury in the setting of COVID-19 may be secondary in nature.

Noncanonical TRAIL Signaling Promotes Myeloid-Derived Suppressor Cell Abundance and Tumor Growth in Cholangiocarcinoma

BACKGROUND & AIMS

Proapoptotic tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling as a cause of cancer cell death is a well-established mechanism. However, TRAIL-receptor (TRAIL-R) agonists have had very limited anticancer activity in human beings, challenging the concept of TRAIL as a potent anticancer agent. Herein, we aimed to define mechanisms by which TRAIL+ cancer cells can leverage noncanonical TRAIL signaling in myeloid-derived suppressor cells (MDSCs) promoting their abundance in murine cholangiocarcinoma (CCA).

METHODS

Multiple immunocompetent syngeneic, orthotopic models of CCA were used. Single-cell RNA sequencing and cellular indexing of transcriptomes and epitopes by sequencing of CD45+ cells in murine tumors from the different CCA models was conducted.

RESULTS

In multiple immunocompetent murine models of CCA, implantation of TRAIL+ murine cancer cells into Trail-r-/- mice resulted in a significant reduction in tumor volumes compared with wild-type mice. Tumor-bearing Trail-r-/- mice had a significant decrease in the abundance of MDSCs owing to attenuation of MDSC proliferation. Noncanonical TRAIL signaling with consequent nuclear factor-κB activation in MDSCs facilitated enhanced MDSC proliferation. Single-cell RNA sequencing and cellular indexing of transcriptomes and epitopes by sequencing of immune cells from murine tumors showed enrichment of a nuclear factor-κB activation signature in MDSCs. Moreover, MDSCs were resistant to TRAIL-mediated apoptosis owing to enhanced expression of cellular FLICE inhibitory protein, an inhibitor of proapoptotic TRAIL signaling. Accordingly, cellular FLICE inhibitory protein knockdown sensitized murine MDSCs to TRAIL-mediated apoptosis. Finally, cancer cell-restricted deletion of Trail significantly reduced MDSC abundance and murine tumor burden.

CONCLUSIONS

Our findings highlight the therapeutic potential of targeting TRAIL+ cancer cells for treatment of a poorly immunogenic cancer.

Deep learning-based phenotyping reclassifies combined hepatocellular-cholangiocarcinoma

Primary liver cancer arises either from hepatocytic or biliary lineage cells, giving rise to hepatocellular carcinoma (HCC) or intrahepatic cholangiocarcinoma (ICCA). Combined hepatocellular- cholangiocarcinomas (cHCC-CCA) exhibit equivocal or mixed features of both, causing diagnostic uncertainty and difficulty in determining proper management. Here, we perform a comprehensive deep learning-based phenotyping of multiple cohorts of patients. We show that deep learning can reproduce the diagnosis of HCC vs. CCA with a high performance. We analyze a series of 405 cHCC-CCA patients and demonstrate that the model can reclassify the tumors as HCC or ICCA, and that the predictions are consistent with clinical outcomes, genetic alterations and in situ spatial gene expression profiling. This type of approach could improve treatment decisions and ultimately clinical outcome for patients with rare and biphenotypic cancers such as cHCC-CCA.

Assessing the capacity of methylated DNA markers of cervical squamous cell carcinoma to discriminate oropharyngeal squamous cell carcinoma in human papillomavirus mediated disease

OBJECTIVE

Early identification of human papillomavirus associated oropharyngeal squamous cell carcinoma (HPV(+)OPSCC) is challenging and novel biomarkers are needed. We hypothesized that a panel of methylated DNA markers (MDMs) found in HPV(+) cervical squamous cell carcinoma (CSCC) will have similar discrimination in HPV(+)OPSCC tissues.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded tissues were obtained from patients with primary HPV(+)OPSCC or HPV(+)CSCC; control tissues included normal oropharynx palatine tonsil (NOP) and cervix (NCS). Using a methylation-specific polymerase chain reaction, 21 previously validated cervical MDMs were evaluated on tissue-extracted DNA. Discrimination between case and control cervical and oropharynx tissue was assessed using area under the curve (AUC).

RESULTS

34 HPV(+)OPSCC, 36 HPV(+)CSCC, 26 NOP, and 24 NCS patients met inclusion criteria. Within HPV(+)CSCC, 18/21 (86%) of MDMs achieved an AUC ≥ 0.9 and all MDMs exhibited better than chance classifications relative to control cervical tissue (all p < 0.001). In contrast, within HPV(+)OPSCC only 5/21 (24%) MDMs achieved an AUC ≥ 0.90 but 19/21 (90%) exhibited better than chance classifications relative to control tonsil tissue (all p < 0.001). Overall, 13/21 MDMs had statistically significant lower AUCs in the oropharyngeal cohort compared to the cervical cohort, and only 1 MDM exhibited a statistically significant increase in AUC.

CONCLUSIONS

Previously validated MDMs exhibited robust performance in independent HPV(+)CSCC patients. However, most of these MDMs exhibited higher discrimination for HPV(+)CSCC than for HPV(+)OPSCC. This suggests that each SCC subtype requires a unique set of MDMs for optimal discrimination. Future studies are necessary to establish an MDM panel for HPV(+)OPSCC.

Allowing Surgical Pathology Fellows to Release Preliminary Reports Increases Learner Independence and Satisfaction

CONTEXT.—

Progressive independence in medicine is critical to building confidence and decisiveness in trainees. However, this can be difficult to accomplish in the strict regulatory environment of pathology.

OBJECTIVE.—

To pilot and adopt a process whereby surgical pathology fellows independently manage a subset of cases and release preliminary reports.

DESIGN.—

Upon program approval, board-certified surgical pathology fellows were eligible for preliminary report sign-out at their discretion. Eligible cases were sent from outside institutions for confirmatory review. Preliminary reports were viewable in the electronic medical record. Safety measures were used to ensure timely release of final reports by attending pathologists.

RESULTS.—

Fellows participating in the pilot (n = 4) released 59 preliminary reports out of 101 cases reviewed (58%), with 1 potentially significant discrepancy between preliminary and final report. Turnaround time was not affected. The process was endorsed by all participants and adopted as standard practice. During the first year, eligible fellows (n = 8) released 123 preliminary reports out of 1260 cases reviewed (9.8%). There were no major diagnostic discrepancies and no effects on turnaround time. The number of preliminary reports released by each fellow was variable (range, 2-48; median, 8), likely a reflection of both external factors (number of trainees on service, volume) and trainee-specific factors (confidence, efficiency).

CONCLUSIONS.—

Fellows showed good judgment when independently managing cases, with just 1 potentially significant discrepancy out of 182 cases (<1%). No patients were adversely impacted. Use of this process varied widely among fellows and may require closer monitoring and encouragement for fellows who are tentative about releasing preliminary reports.

Immune Marker Spatial Distribution and Clinical Outcome after PD-1 Blockade in Mismatch Repair-deficient, Advanced Colorectal Carcinomas

PURPOSE

Targeting the programmed cell death protein 1 (PD-1)/programmed cell death ligand 1 (PD-L1) interaction has led to durable responses in fewer than half of patients with mismatch repair-deficient (MMR-d) advanced colorectal cancers. Immune contexture, including spatial distribution of immune cells in the tumor microenvironment (TME), may predict immunotherapy outcome.

EXPERIMENTAL DESIGN

Immune contexture and spatial distribution, including cell-to-cell distance measurements, were analyzed by multiplex immunofluorescence (mIF) in primary colorectal cancers with d-MMR (N = 33) from patients treated with anti-PD-1 antibodies. By digital image analysis, density, ratio, intensity, and spatial distribution of PD-L1, PD-1, CD8, CD3, CD68, LAG3, TGFβR2, MHC-I, CD14, B2M, and pan-cytokeratin were computed. Feature selection was performed by regularized Cox regression with LASSO, and a proportional hazards model was fitted to predict progression-free survival (PFS).

RESULTS

For predicting survival among patients with MMR-d advanced colorectal cancer receiving PD-1 blockade, cell-to-cell distance measurements, but not cell densities or ratios, achieved statistical significance univariately. By multivariable feature selection, only mean number of PD-1+ cells within 10 μm of a PD-L1+ cell was significantly predictive of PFS. Dichotomization of this variable revealed that those with high versus low values had significantly prolonged PFS [median not reached (>83 months) vs. 8.5 months (95% confidence interval (95% CI), 4.7-NR)] with a median PFS of 28.4 months for all patients [adjusted HR (HRadj) = 0.14; 95% CI, 0.04-0.56; P = 0.005]. Expression of PD-1 was observed on CD8+ T cells; PD-L1 on CD3+ and CD8+ T lymphocytes, macrophages (CD68+), and tumor cells.

CONCLUSIONS

In d-MMR colorectal cancers, PD-1+ to PD-L1+ receptor to ligand proximity is a potential predictive biomarker for the effectiveness of PD-1 blockade.

Long-Term Outcomes and Risk of Pancreatic Cancer in Intraductal Papillary Mucinous Neoplasms

Importance

Intraductal papillary mucinous neoplasms (IPMNs) are pancreatic cysts that can give rise to pancreatic cancer (PC). Limited population data exist on their prevalence, natural history, or risk of malignant transformation (IPMN-PC).

Objective

To fill knowledge gaps in epidemiology of IPMNs and associated PC risk by estimating population prevalence of IPMNs, associated PC risk, and proportion of IPMN-PC.

Design, Setting, and Participants

: This retrospective cohort study was conducted in Olmsted County, Minnesota. Using the Rochester Epidemiology Project (REP), patients aged 50 years and older with abdominal computed tomography (CT) scans between 2000 and 2015 were randomly selected (CT cohort). All patients from the REP with PC between 2000 and 2019 were also selected (PC cohort). Data were analyzed from November 2021 through August 2023.

Main outcomes and Measures

CIs for PC incidence estimates were calculated using exact methods with the Poisson distribution. Cox models were used to estimate age, sex, and stage-adjusted hazard ratios for time-to-event end points.

Results

The CT cohort included 2114 patients (1140 females [53.9%]; mean [SD] age, 68.6 [12.1] years). IPMNs were identified in 231 patients (10.9%; 95% CI, 9.7%-12.3%), most of which were branch duct (210 branch-duct [90.9%], 16 main-duct [6.9%], and 5 mixed [2.2%] IPMNs). There were 5 Fukuoka high-risk (F-HR) IPMNs (2.2%), 39 worrisome (F-W) IPMNs (16.9%), and 187 negative (F-N) IPMNs (81.0%). After a median (IQR) follow-up of 12.0 (8.1-15.3) years, 4 patients developed PC (2 patients in F-HR and 2 patients in F-N groups). The PC incidence rate per 100 person years for F-HR IPMNs was 34.06 incidents (95% CI, 4.12-123.02 incidents) and not significantly different for patients with F-N IPMNs compared with patients without IPMNs (0.16 patients; 95% CI, 0.02-0.57 patients vs 0.11 patients; 95% CI, 0.06-0.17 patients; P = .62). The PC cohort included 320 patients (155 females [48.4%]; mean [SD] age, 72.0 [12.3] years), and 9.8% (95% CI, 7.0%-13.7%) had IPMN-PC. Compared with 284 patients with non-IPMN PC, 31 patients with IPMN-PC were older (mean [SD] age, 76.9 [9.2] vs 71.3 [12.5] years; P = .02) and more likely to undergo surgical resection (14 patients [45.2%] vs 60 patients [21.1%]; P = .003) and more-frequently had nonmetastatic PC at diagnosis (20 patients [64.5%] vs 130 patients [46.8%]; P = .047). Patients with IPMN-PC had better survival (adjusted hazard ratio, 0.62; 95% CI, 0.40-0.94; P = .03) than patients with non-IPMN PC.

Conclusions and Relevance

In this study, CTs identified IPMNs in approximately 10% of patients aged 50 years or older. PC risk in patients with F-N IPMNs was low and not different compared with patients without IPMNs; approximately 10% of patients with PC had IPMN-PC, and they had better survival compared with patients with non-IPMN PC.

Performance of an Artificial Intelligence Model for Recognition and Quantitation of Histologic Features of Eosinophilic Esophagitis on Biopsy Samples

We have developed an artificial intelligence (AI)-based digital pathology model for the evaluation of histologic features related to eosinophilic esophagitis (EoE). In this study, we evaluated the performance of our AI model in a cohort of pediatric and adult patients for histologic features included in the Eosinophilic Esophagitis Histologic Scoring System (EoEHSS). We collected a total of 203 esophageal biopsy samples from patients with mucosal eosinophilia of any degree (91 adult and 112 pediatric patients) and 10 normal controls from a prospectively maintained database. All cases were assessed by a specialized gastrointestinal (GI) pathologist for features in the EoEHSS at the time of original diagnosis and rescored by a central GI pathologist (R.K.M.). We subsequently analyzed whole-slide image digital slides using a supervised AI model operating in a cloud-based, deep learning AI platform (Aiforia Technologies) for peak eosinophil count (PEC) and several histopathologic features in the EoEHSS. The correlation and interobserver agreement between the AI model and pathologists (Pearson correlation coefficient [rs] = 0.89 and intraclass correlation coefficient [ICC] = 0.87 vs original pathologist; rs = 0.91 and ICC = 0.83 vs central pathologist) were similar to the correlation and interobserver agreement between pathologists for PEC (rs = 0.88 and ICC = 0.91) and broadly similar to those for most other histologic features in the EoEHSS. The AI model also accurately identified PEC of >15 eosinophils/high-power field by the original pathologist (area under the curve [AUC] = 0.98) and central pathologist (AUC = 0.98) and had similar AUCs for the presence of EoE-related endoscopic features to pathologists' assessment. Average eosinophils per epithelial unit area had similar performance compared to AI high-power field-based analysis. Our newly developed AI model can accurately identify, quantify, and score several of the main histopathologic features in the EoE spectrum, with agreement regarding EoEHSS scoring which was similar to that seen among GI pathologists.

Artificial intelligence-based reticulin proportionate area - a novel histological outcome predictor in hepatocellular carcinoma

AIMS

Reticulin stain is used routinely in the histological evaluation of hepatocellular carcinoma (HCC). The goal of this study was to assess whether the histological reticulin proportionate area (RPA) in HCCs predicts tumour-related outcomes.

METHODS AND RESULTS

We developed and validated a supervised artificial intelligence (AI) model that utilises a cloud-based, deep-learning AI platform (Aiforia Technologies, Helsinki, Finland) to specifically recognise and quantify the reticulin framework in normal livers and HCCs using routine reticulin staining. We applied this reticulin AI model to a cohort of consecutive HCC cases from patients undergoing curative resection between 2005 and 2015. A total of 101 HCC resections were included (median age = 68 years, 64 males, median follow-up time = 49.9 months). AI model RPA reduction of > 50% (compared to normal liver tissue) was predictive of metastasis [hazard ratio (HR) = 3.76, P = 0.004, disease-free survival (DFS, HR = 2.48, P < 0.001) and overall survival (OS), HR = 2.80, P = 0.001]. In a Cox regression model, which included clinical and pathological variables, RPA decrease was an independent predictor of DFS and OS and the only independent predictor of metastasis. Similar results were found in the moderately differentiated HCC subgroup (WHO grade 2), in which reticulin quantitative analysis was an independent predictor of metastasis, DFS and OS.

CONCLUSION

Our data indicate that decreased RPA is a strong predictor of various HCC-related outcomes, including within the moderately differentiated subgroup. Reticulin, therefore, may represent a novel and important prognostic HCC marker, to be further explored and validated.

Targeting ERBB2/HER2 genetic alterations: an expanding therapeutic opportunity in gastrointestinal cancers

HER2 amplification and/or activating variations of its protein, human epidermal growth factor receptor 2 (HER2), are associated with distinct clinical and pathological features in gastrointestinal tumors, including a worse overall prognosis and a higher incidence of metastastic lesions in the central nervous system. Notably, the role of HER2 as a therapeutic target continues to expand beyond the scope of breast and gastroesophageal tumors, now encompassing colorectal and biliary tract cancers (BTCs), among others. In parallel, there is a burgeoning array of therapeutic agents designed to inhibit the activity of the HER2 pathway, including monoclonal antibodies, orally available tyrosine kinase inhibitors, bispecific antibodies, and antibody-drug conjugate compounds. In this comprehensive review, we will explore the current body of evidence that supports the implementation of HER2-targeting strategies in the treatment of patients with gastric, esophageal, colorectal, and biliary tract tumors. We will also describe testing methods for HER2 status in clinical practice, including immunohistochemistry (IHC), and its correlation with next-generation sequencing-based techniques. Additionally, we will review the key treatment-related adverse events associated with specific anti-HER2 agents, emphasizing the need for early diagnosis and effective management. Furthermore, a critical aspect of this exploration is determining the optimal treatment sequencing among the available therapies, which will be pivotal in enhancing treatment outcomes.

Therapeutic Efficacy of Temsirolimus in a Patient-derived Model of Metastatic Fibrolamellar Hepatocellular Carcinoma

BACKGROUND/AIM

Fibrolamellar hepatocellular carcinoma (FLHCC) is a rare tumor presenting in younger patients without chronic liver disease. Up to 80-100% develop recurrent disease, necessitating additional surgery or systemic treatment. Systemic options and pre-clinical treatment studies are lacking. We previously described patient-derived xenograft (PDX) development, allowing for pre-clinical studies. Herein, we develop FLHCC PDX models and utilize these to define tumor characteristics and determine the efficacy of systemic agents.

MATERIALS AND METHODS

Primary and lymph node metastatic tumor tissues were obtained at the time of FLHCC resection in two patients. Tumor lysates were screened for protein upregulation. Cell lines were generated from metastatic and primary tumor tissue. The viability of the cell lines was assessed after treatment with temsirolimus, gemcitabine/oxaliplatin, and FOLFIRINOX. Two PDX models were developed from metastatic tissue. For in vivo studies, tumor-bearing mice were treated with temsirolimus, FOLFIRINOX, and Gemcitabine/oxaliplatin.

RESULTS

PDX models were successfully generated from metastatic FLHCC, which closely recapitulated the original tumor. Upregulation of mTOR was seen in metastatic tissue compared to primary tumors. Cell lines from metastatic tissue demonstrated significant sensitivity to temsirolimus. In vivo testing of PDX models demonstrated a significant response to single-agent temsirolimus with minimal toxicity.

CONCLUSION

Herein, we demonstrate the feasibility of developing PDX models that closely recapitulate FLHCC. Upregulation of mTOR was seen in metastatic tissue compared to primary tissue. The efficacy of mTOR inhibition with temsirolimus treatment suggests that the upregulation of the mTOR pathway may be a significant mechanism for growth in metastatic lesions and a potential target for therapeutics.

Identification of a ΔNp63-Dependent Basal-Like A Subtype-Specific Transcribed Enhancer Program (B-STEP) in Aggressive Pancreatic Ductal Adenocarcinoma

A major hurdle to the application of precision oncology in pancreatic cancer is the lack of molecular stratification approaches and targeted therapy for defined molecular subtypes. In this work, we sought to gain further insight and identify molecular and epigenetic signatures of the Basal-like A pancreatic ductal adenocarcinoma (PDAC) subgroup that can be applied to clinical samples for patient stratification and/or therapy monitoring. We generated and integrated global gene expression and epigenome mapping data from patient-derived xenograft models to identify subtype-specific enhancer regions that were validated in patient-derived samples. In addition, complementary nascent transcription and chromatin topology (HiChIP) analyses revealed a Basal-like A subtype-specific transcribed enhancer program in PDAC characterized by enhancer RNA (eRNA) production that is associated with more frequent chromatin interactions and subtype-specific gene activation. Importantly, we successfully confirmed the validity of eRNA detection as a possible histologic approach for PDAC patient stratification by performing RNA-ISH analyses for subtype-specific eRNAs on pathologic tissue samples. Thus, this study provides proof-of-concept that subtype-specific epigenetic changes relevant for PDAC progression can be detected at a single-cell level in complex, heterogeneous, primary tumor material.

IMPLICATIONS

Subtype-specific enhancer activity analysis via detection of eRNAs on a single-cell level in patient material can be used as a potential tool for treatment stratification.

Cancer "Avatars": Patient-Derived Xenograft Growth Correlation with Postoperative Recurrence and Survival in Pancreaticobiliary Cancer

BACKGROUND

Pancreaticobiliary (PB) cancers are a diverse group of cancers with poor prognoses and high rates of recurrence after resection. Patient-derived xenografts (PDX), created from surgical specimens, provide a reliable preclinical research platform and high-fidelity cancer model from which to study these malignancies with consistent recapitulation of their original patient tumors in vivo. However, the relationship between PDX engraftment success (growth or no growth) and patient oncologic outcomes has not been well studied. We sought to evaluate the correlation between successful PDX engraftment and survival in several PB exocrine carcinomas, including the pancreatic and biliary tract.

STUDY DESIGN

In accordance with IRB and Institutional Animal Care and Use Committee protocols and with appropriate consent and approval, excess tumor tissue obtained from surgical patients was implanted into immunocompromised mice. Mice were monitored for tumor growth to determine engraftment success. PDX tumors were verified to recapitulate their tumors of origin by a hepatobiliary pathologist. Xenograft growth was correlated with clinical recurrence and overall survival data.

RESULTS

A total of 384 PB xenografts were implanted. The successful engraftment rate was 41% (158/384). We found that successful PDX engraftment was highly associated with both recurrence-free survival (p < 0.001) and overall survival (p < 0.001) outcomes. Successful PDX tumor generation occurs significantly in advance of clinical recurrences in their corresponding patients (p < 0.001).

CONCLUSIONS

Successful PB cancer PDX models predict recurrence and survival across tumor types and may provide critical lead time to alter patients' surveillance or treatment plans before cancer recurrence.

Digital Hepatic Iron Content: An Artificial Intelligence Model for Spatially Resolved Histologic Iron Quantitative Analysis in Liver Samples

Currently, the precise evaluation of tissue hepatic iron content (HIC) requires laboratory testing using tissue-destructive methods based on colorimetry or spectrophotometry. To maximize the use of routine histologic stains in this context, we developed an artificial intelligence (AI) model for the recognition and spatially resolved measurement of iron in liver samples. Our AI model was developed using a cloud-based, supervised deep learning platform (Aiforia Technologies). Using digitized Pearl Prussian blue iron stain whole slide images representing the full spectrum of changes seen in hepatic iron overload, our training set consisted of 59 cases, and our validation set consisted of 19 cases. The study group consisted of 98 liver samples from 5 different laboratories, for which tissue quantitative analysis using inductively coupled plasma mass spectrometry was available, collected between 2012 and 2022. The correlation between the AI model % iron area and HIC was Rs = 0.93 for needle core biopsy samples (n = 73) and Rs = 0.86 for all samples (n = 98). The digital hepatic iron index (HII) was highly correlated with HII > 1 (area under the curve [AUC] = 0.93) and HII > 1.9 (AUC = 0.94). The percentage area of iron within hepatocytes (vs Kupffer cells and portal tract iron) identified patients with any hereditary hemochromatosis-related mutations (either homozygous or heterozygous) (AUC = 0.65, P = .01) with at least similar accuracy than HIC, HII, and any histologic iron score. The correlation between the Deugnier and Turlin score and the AI model % iron area for all patients was Rs = 0.87 for total score, Rs = 0.82 for hepatocyte iron score, and Rs = 0.84 for Kupffer cell iron score. Iron quantitative analysis using our AI model was highly correlated with both detailed histologic scoring systems and tissue quantitative analysis using inductively coupled plasma mass spectrometry and offers advantages (related to the spatial resolution of iron analysis and the nontissue-destructive nature of the test) over standard quantitative methods.

How Molecular Discoveries Have Changed Liver Tumor Pathology: A Brief Review

CONTEXT.—

Recent molecular discoveries have led to improved understanding of tumor biology and the development of new diagnostic assays.

OBJECTIVE.—

To review primarily 3 examples of liver tumors and to briefly illustrate how recent molecular discoveries have altered clinical liver pathology practice.

DATA SOURCES.—

First, we will discuss fibrolamellar carcinoma, which will be the main focus of discussion, as an example for new diagnostic tests that have been developed as a result of molecular discoveries. Additional information on the role of molecular diagnostics in hepatocellular adenoma and hepatocellular carcinoma will be provided. Second, we will use the example of epithelioid hemangioendothelioma as an example of how new diagnostic tools, based on molecular discoveries, may support improved prognostication. Finally, we will use the example of intrahepatic cholangiocarcinoma as an example of a liver tumor where new molecular discoveries have identified tractable therapeutic targets and led to new effective therapies. This portion of the manuscript will also include a description of the anatomic and molecular differences between intrahepatic, hilar, and extrahepatic cholangiocarcinoma.

CONCLUSIONS.—

Fueled by molecular discoveries, new and better diagnostic tests and therapeutic targets have improved clinical care in patients affected by liver tumors.

HILPDA promotes NASH-driven HCC development by restraining intracellular fatty acid flux in hypoxia

BACKGROUND & AIMS

The prevalence of non-alcoholic steatohepatitis (NASH)-driven hepatocellular carcinoma (HCC) is rising rapidly, yet its underlying mechanisms remain unclear. Herein, we aim to determine the role of hypoxia-inducible lipid droplet associated protein (HILPDA)/hypoxia-inducible gene 2 (HIG2), a selective inhibitor of intracellular lipolysis, in NASH-driven HCC.

METHODS

The clinical significance of HILPDA was assessed in human NASH-driven HCC specimens by immunohistochemistry and transcriptomics analyses. The oncogenic effect of HILPDA was assessed in human HCC cells and in 3D epithelial spheroids upon exposure to free fatty acids and either normoxia or hypoxia. Lipidomics profiling of wild-type and HILPDA knockout HCC cells was assessed via shotgun and targeted approaches. Wild-type (Hilpdafl/fl) and hepatocyte-specific Hilpda knockout (HilpdaΔHep) mice were fed a Western diet and high sugar in drinking water while receiving carbon tetrachloride to induce NASH-driven HCC.

RESULTS

In patients with NASH-driven HCC, upregulated HILPDA expression is strongly associated with poor survival. In oxygen-deprived and lipid-loaded culture conditions, HILPDA promotes viability of human hepatoma cells and growth of 3D epithelial spheroids. Lack of HILPDA triggered flux of polyunsaturated fatty acids to membrane phospholipids and of saturated fatty acids to ceramide synthesis, exacerbating lipid peroxidation and apoptosis in hypoxia. The apoptosis induced by HILPDA deficiency was reversed by pharmacological inhibition of ceramide synthesis. In our experimental mouse model of NASH-driven HCC, HilpdaΔHep exhibited reduced hepatic steatosis and tumorigenesis but increased oxidative stress in the liver. Single-cell analysis supports a dual role of hepatic HILPDA in protecting HCC cells and facilitating the establishment of a pro-tumorigenic immune microenvironment in NASH.

CONCLUSIONS

Hepatic HILPDA is a pivotal oncometabolic factor in the NASH liver microenvironment and represents a potential novel therapeutic target.

IMPACT AND IMPLICATIONS

Non-alcoholic steatohepatitis (NASH, chronic metabolic liver disease caused by buildup of fat, inflammation and damage in the liver) is emerging as the leading risk factor and the fastest growing cause of hepatocellular carcinoma (HCC), the most common form of liver cancer. While curative therapeutic options exist for HCC, it frequently presents at a late stage when such options are no longer effective and only systemic therapies are available. However, systemic therapies are still associated with poor efficacy and some side effects. In addition, no approved drugs are available for NASH. Therefore, understanding the underlying metabolic alterations occurring during NASH-driven HCC is key to identifying new cancer treatments that target the unique metabolic needs of cancer cells.

Noncanonical TRAIL Signaling Promotes Myeloid-Derived Suppressor Cell Abundance and Tumor Progression in Cholangiocarcinoma

Proapoptotic tumor necrosis factor-related apoptosis-inducing ligand (TRAIL) signaling as a cause of cancer cell death is a well-established mechanism. However, TRAIL-receptor (TRAIL-R) agonists have had very limited anticancer activity in humans, challenging the concept of TRAIL as a potent anticancer agent. Herein, we demonstrate that TRAIL + cancer cells can leverage noncanonical TRAIL signaling in myeloid-derived suppressor cells (MDSCs) promoting their abundance in murine cholangiocarcinoma (CCA). In multiple immunocompetent syngeneic, orthotopic murine models of CCA, implantation of TRAIL + murine cancer cells into Trail-r -/- mice resulted in a significant reduction in tumor volumes compared to wild type mice. Tumor bearing Trail-r -/- mice had a significant decrease in the abundance of MDSCs due to attenuation of MDSC proliferation. Noncanonical TRAIL signaling with consequent NF-κB activation in MDSCs facilitated enhanced MDSC proliferation. Single cell RNA sequencing and cellular indexing of transcriptomes and epitopes by sequencing (CITE-Seq) of CD45 + cells in murine tumors from three distinct immunocompetent CCA models demonstrated a significant enrichment of an NF-κB activation signature in MDSCs. Moreover, MDSCs were resistant to TRAIL-mediated apoptosis due to enhanced expression of cellular FLICE inhibitory protein (cFLIP), an inhibitor of proapoptotic TRAIL signaling. Accordingly, cFLIP knockdown sensitized murine MDSCs to TRAIL-mediated apoptosis. Finally, cancer cell-restricted deletion of Trail significantly reduced MDSC abundance and murine tumor burden. In summary, our findings define a noncanonical TRAIL signal in MDSCs and highlight the therapeutic potential of targeting TRAIL + cancer cells for the treatment of a poorly immunogenic cancer.

Abstract 6648: Prediction of anti-PD-1 efficacy based on immune marker densities and their spatial distribution in colorectal cancer

Background: Immune checkpoint inhibitors (ICIs) have revolutionized the treatment of patients with deficient DNA mismatch repair (d-MMR) metastatic colorectal cancer (CRC), yet less than half of patients receive clinical benefit. We hypothesized that immune contexture including spatial distribution of cells expressing immune molecules in the tumor microenvironment may predict immunotherapy outcome. Methods: Primary CRC tissues from consecutive patients with d-MMR metastatic CRC (N=33) were treated with anti-PD-1 antibodies at Mayo Clinic Comprehensive Cancer Center (2015-2018). Tumors were stained for PD-L1, PD-1, CD8, CD3, CD68, LAG3, TGFβR2, MHC-I, CD14, B2M, DAPI and pan-cytokeratin in 5 compartments (overall tumor, tumor epithelia, tumor stroma, peritumor inside vs outside) by multiplex immunofluorescence with digital image analysis. Features computed within each image analysis region included positive cell density, fraction of positive cell types, intensity of positive cells, and spatial distribution between distinct cell types (distances measured using image analysis software). Prior to model fitting, feature selection was performed using regularized Cox regression with LASSO. Regularization parameter was chosen based on 5-fold cross validation. A Cox proportional hazards model was fitted to predict patient progression-free survival (PFS).

Results: Among patients with d-MMR CRCs, 16/33 (48.4%) were female, 10 received first-line ICI therapy, and 23 had received &gt; 1 prior chemotherapy regimen. Median age was 61.6 years (IQR of 49.4, 73.7). Eight patients (24.2%) harbored BRAFV600E, 9 (27.2%) had mutant KRAS, and median PFS was 22.2 months (95% CI: 11.8, NR) with 20 events. PD-L1 was expressed in tumor cells, CD68+ macrophages, and CD3+ T lymphocytes. PD-1 expression on CD8+ T lymphocytes was also observed. By univariate analysis, only cell-cell distance readouts achieved statistical significance. Multivariable feature selection identified the mean number of PD-1+ cells within 10 microns of a PD-L1+ cell in the overall tumor as the strongest predictor of anti-PD-1 efficacy, and was significantly associated with PFS (HR=0.87, 95% CI: 0.79-0.95, p&lt; 0.001). In contrast, the ratio of PD-1+/PD-L1+ cells was not predictive of treatment efficacy (p= 0.47), thereby underscoring the importance of spatial distribution for PFS prediction.

Conclusion: The mean number of PD-1+ cells in proximity to PD-L1+ cells in tumors was a predictive biomarker of anti-PD-1 efficacy. Confirmatory studies are warranted.

Citation Format: Bahar Saberzadeh-Ardestani, Rondell P. Graham, Qian Shi, Eze Ahanonu, Sara McMahon, Crystal Williams, Antony Hubbard, Wenjun Zhang, Andrea Muranyi, Dongyao Yan, Kandavel Shanmugam, Frank A. Sinicrope. Prediction of anti-PD-1 efficacy based on immune marker densities and their spatial distribution in colorectal cancer [abstract]. In: Proceedings of the American Association for Cancer Research Annual Meeting 2023; Part 1 (Regular and Invited Abstracts); 2023 Apr 14-19; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2023;83(7_Suppl):Abstract nr 6648.

Clinical Testing for Tumor Cell-Free DNA: College of American Pathologists Proficiency Programs Reveal Practice Trends

CONTEXT.—

Clinical testing for tumor cell-free DNA (cfDNA) has evolved rapidly, but no practice guidelines exist.

OBJECTIVE.—

To summarize cfDNA laboratory practices based on self-reporting and assess preanalytical, analytical, and postanalytical trends that may influence the quality, accuracy, and consistency of cfDNA testing.

DESIGN.—

Data were derived from the College of American Pathologists cfDNA proficiency testing program submitted by 101 participating laboratories from 2018 to 2019.

RESULTS.—

Most laboratories performing clinical circulating tumor DNA testing are commercial/nonhospital (71.2%; 72 of 101) and international (77.2%; 78 of 101) laboratories. Commercial laboratories had higher monthly test volumes than hospital-based laboratories (median, 36 versus 7-8) and tended to have larger gene panels (median, 50 versus 11 genes) when panel-based testing was offered. The main clinical indications include therapy selection and treatment/disease monitoring. Plasma is the most commonly accepted specimen, which is predominantly collected in cell-stabilizing tubes. Equal proportions of laboratories use next-generation sequencing (NGS) and non-NGS methods to assess key genes, including EGFR, BRAF, KRAS, NRAS, and IDH1. Most laboratories reported a lower limit of detection (LLOD) of 0.5%, variant allele frequency or less, which did not differ by method, NGS or non-NGS, except for EGFR. Sixty-five percent (17 of 26) of laboratories using the US Food and Drug Administration (FDA)-approved non-NGS EGFR assay report analytical sensitivities higher than 0.5%, as compared to 15% (16 of 104) of laboratories using an alternative NGS or non-NGS method. There is also a wider range in LLODs obtained for the FDA-approved EGFR assay than nonapproved assays.

CONCLUSIONS.—

These results highlight emerging practice trends and serve as a foundation to initiate future practice recommendations.

High Interobserver Variability among Pathologists Using Combined Positive Score to Evaluate PD-L1 Expression in Gastric, Gastroesophageal Junction and Esophageal Adenocarcinoma

Reliable, reproducible methods to interpret programmed death ligand-1 (PD-L1) expression on tumor cells (TC) and immune cells (IC) are needed for pathologists to inform decisions associated with checkpoint inhibitor therapies. Our international study compared interpathologist agreement of PD-L1 expression using combined positive score (CPS) under standardized conditions on samples from patients with gastric/gastroesophageal junction/esophageal adenocarcinoma. Tissue sections from 100 adenocarcinoma pre-treatment biopsies were stained in a single laboratory using the PD-L1 IHC 28-8 and 22C3(Agilent) pharmDx immunohistochemical assays. PD-L1 CPS was evaluated by 12 pathologists on scanned whole slide images of these biopsies before and after a 2-hour CPS training session by Agilent. Additionally, pathologists determined PD-L1 positive TC, IC, and total viable TC on a single tissue fragment from 35 of 100 biopsy samples. Scoring agreement among pathologists was assessed using the intraclass correlation coefficient (ICC). Interobserver variability for CPS for 100 biopsies was high with only fair agreement among pathologists both pre- (range 0.45 to 0.55) and post-training (range 0.56 to 0.57) for both assays. For the 35 single biopsy samples, poor/fair agreement was also observed for the total number viable TC (ICC 0.09), number of PD-L1 positive IC (ICC 0.19), number of PD-L1 positive TC (ICC 0.54), and calculated CPS (ICC 0.14), while calculated TC score (positive TC/Total TC) showed excellent agreement (ICC 0.82). Retrospective histologic review of samples with the poorest interpathologist agreement revealed (1) ambiguous identification of positively staining stromal cells, (2) faint or variable intensity of staining, (3) difficulty in distinguishing membranous from cytoplasmic tumor staining, and (4) cautery and crush artifact, as possible confounding factors. These results emphasize the need for objective techniques to standardize the interpretation of PD-L1 expression when using the CPS methodology on gastric/gastroesophageal junction cancer biopsies to accurately identify patients most likely to benefit from immune checkpoint inhibitor therapy.

Rectal cancer pelvic recurrence: imaging patterns and key concepts to guide treatment planning

For rectal cancer, MRI plays an important role in assessing extramural tumor spread and informs surgical planning. The contemporary standardized management of rectal cancer with total mesorectal excision guided by imaging-based risk stratification has dramatically improved patient outcomes. Colonoscopy and CT are utilized in surveillance after surgery to detect intraluminal and extramural recurrence, respectively; however, local recurrence of rectal cancer remains a challenge because postoperative changes such as fat necrosis and fibrosis can resemble tumor recurrence; additionally, mucinous adenocarcinoma recurrence may mimic fluid collection or abscess on CT. MRI and ¹⁸F-FDG PET are problem-resolving modalities for equivocal imaging findings on CT. Treatment options for recurrent rectal cancer include pelvic exenteration to achieve radical (R0 resection) resection and intraoperative radiation therapy. After pathologic diagnosis of recurrence, imaging plays an essential role for evaluating the feasibility and approach of salvage surgery. Patterns of recurrence can be divided into axial/central, anterior, lateral, and posterior. Some lateral and posterior recurrence patterns especially in patients with neurogenic pain are associated with perineural invasion. Cross-sectional imaging, especially MRI and ¹⁸F-FDG PET, permit direct visualization of perineural spread, and contribute to determining the extent of resection. Multidisciplinary discussion is essential for treatment planning of locally recurrent rectal cancer. This review article illustrates surveillance strategy after initial surgery, imaging patterns of rectal cancer recurrence based on anatomic classification, highlights imaging findings of perineural spread on each modality, and discusses how resectability and contemporary surgical approaches are determined based on imaging findings.

Phase Ib open-label study to evaluate safety, tolerability, immunogenicity, and efficacy of multiple subcutaneous injections of PolyPEPI1018 vaccine as an add-on immunotherapy to TAS-102 in participants with late-stage microsatellite-stable metastatic colorectal cancer (MSS mCRC; OBERTO-201)

147

Background: PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine containing 12 immunogenic epitopes derived from 7 cancer testis antigens (CTAs) frequently expressed in patients with colorectal cancer (CRC). PolyPEPI1018 successfully induced anticancer immunity and triggered recruitment and infiltration of cytotoxic T cells into the tumor of MSS mCRC subjects demonstrating also early evidence of clinical activity, in first-line mCRC. Here we report the initial results of the phase Ib study of PolyPEPI1018 vaccine plus trifluridine/tipiracil (TAS-102) in late-stage mCRC patients. Methods: Patients with MSS mCRC who have progressed on ≤2 lines of prior chemotherapy regimen for mCRC received PolyPEPI1018 subcutaneously on days 1 and 15 and TAS-102 orally twice daily on days 1-5 and 8-12 of a 28-day cycle. Treatment continued for up to 7 cycles until disease progression or unacceptable toxicity. Immunomonitoring was performed at both blood and tumor levels prior to- and on study treatment. The primary endpoint of the study was safety and tolerability. Data on objective response rate (ORR), disease control rate (DCR), progression-free survival (PFS), overall survival (OS) and correlation studies will be also presented. Results: 15 patients (67% male) started treatment. At baseline, median age was 55 years (range 31–71), 73% had liver metastases and the primary tumor site was colon-sigmoid in 40% and rectum in 33%. The combination was well-tolerated; most common side effect related to PolyPEPI1018 was Grade (Gr) 1-2 local skin reactions in 93% of patients. Gr 3 events. There were no Gr 4 or 5 events. The ORR was 0% and the DCR was 50%. The mPFS was 2.5 months (95%CI 2.1-NR). At the data cut-off (September 7, 2022), the mOS has not been reached; median follow-up was 4.0 months (95% CI 2.2-4.4). Post-treatment, vaccine-specific T cell responses were detected ex vivo in the PBMC of 4/5 subjects tested. In addition, one subject who had no detectable T cell response at peripheral level, responded at the tumor level with more than 300% increase of both CD3+ and CD8+ tumor-infiltrating lymphocytes compared to baseline. Patients with increased PFS (≥ 16 weeks) had robust vaccine-specific T cell responses. Conclusions: To our knowledge, this is the first phase Ib study investigating combination of a cancer vaccine with TAS-102 chemotherapy in advanced MSS mCRC. Our results show that PolyPEPI1018 plus TAS-102 was well-tolerated with few grade 3 AEs beyond what is expected with TAS-102 monotherapy. PolyPEPI1018 induced immunological responses at both peripheral and tumor level, albeit no objective tumor responses could be detected. The study is on-going for the collection of overall survival data. Clinical trial information: NCT05130060 .

Perianal Basal Cell Carcinoma: 35-Year Experience

BACKGROUND

Basal cell carcinoma of the perianal region is a rare anorectal disease. This condition is not related to exposure to ultraviolet radiation. Because of the low prevalence and poor detection, there is a paucity of data relating to this condition in the literature. Perianal basal cell carcinoma presents surgical challenges different from other anatomic locations and may not share the same prevalence or natural history. Here, we describe the largest series to date on the surgical management of perianal basal cell carcinoma.

OBJECTIVE

We aimed to present our 35-year experience in managing perianal basal cell carcinoma in this study.

DESIGN

This was a retrospective single-center analysis.

SETTING

The study was conducted at a large tertiary referral academic health care system.

PATIENTS

All patients undergoing surgical management of pathology confirmed perianal basal cell carcinoma.

INTERVENTIONS

All patients underwent surgical management of their disease.

MAIN OUTCOME MEASURES

The primary outcomes were disease recurrence, mortality, and wound complications.

RESULTS

A total of 29 patients were identified with an average follow-up of 5.5 years. At index presentation, 27.6% of patients had multiple basal cell carcinoma in other anatomic locations. Ninety-three percent of patients were adequately treated with local excision, but 60% had wound dehiscence at the time of their first follow-up visit. Ultimately, there were no recurrences or disease-related mortality during the follow-up period.

LIMITATIONS

Limitations to our study include its nonrandomized retrospective nature, single-institution experience, and small patient sample size.

CONCLUSIONS

Perianal basal cell carcinoma carries a high rate of synchronous presentation in other locations and should prompt a thorough evaluation. Perianal basal cell carcinomas can and should be successfully treated with local excision despite the high rate of wound complications. See Video Abstract at http://links.lww.com/DCR/B883 .Carcinoma perianal de células basales: 35 años de experienciaANTECEDENTES:El carcinoma de células basales de la región perianal es una enfermedad anorrectal rara. Esta condición no está relacionada con la exposición a la radiación ultravioleta. Debido a la baja prevalencia y detección pobre, hay escasez de datos relacionados con esta condición en la literatura. El carcinoma de células basales perianal presenta diferentes desafíos quirúrgicos en otras ubicaciones anatómicas y puede no compartir la misma prevalencia o historia natural. A continuación, describimos la serie más grande hasta la fecha sobre el tratamiento quirúrgico del carcinoma de células basales perianal.OBJETIVO:Presentar nuestra experiencia de 35 años en el manejo del carcinoma de células basales perianal.DISEÑO:Este fue un análisis retrospectivo de un solo centro.ENTORNO CLINICO:El estudio se llevó a cabo en un gran centro de salud académico de referencia terciaria.PACIENTES:Todos los pacientes sometidos a tratamiento quirúrgico con patología confirmatoria de carcinoma basocelular perianal.INTERVENCIONES:Todos los pacientes fueron sometidos a tratamiento quirúrgico de su enfermedad.PRINCIPALES MEDIDAS DE RESULTADO:Los resultados primarios fueron la recurrencia de la enfermedad, mortalidad, y complicaciones de la herida.RESULTADOS:Se identificaron un total de 29 pacientes con un seguimiento promedio de 5.5 años. El 27,6% de los pacientes tenían carcinoma basocelular múltiple en otras localizaciones anatómicas en la presentación inicial. El 93% de los pacientes fueron tratados adecuadamente con escisión local, pero el 60% tuvo dehiscencia de la herida en el momento de la primera visita de seguimiento. En última instancia, no hubo recurrencias ni mortalidad relacionada con la enfermedad durante el período de seguimiento.LIMITACIONES:Las limitaciones de nuestro estudio incluyen su naturaleza retrospectiva no aleatorizada, la experiencia de una sola institución y el tamaño pequeño de la muestra de pacientes.CONCLUSIONES:El carcinoma de células basales perianal tiene una alta tasa de presentación sincrónica en otras localizaciones y debe dar lugar a una evaluación exhaustiva. Los CBC perianales pueden y deben ser tratados exitosamente con escisión local a pesar de la alta tasa de complicaciones de herida. Consulte Video Resumen en http://links.lww.com/DCR/B883 . (Tradducción-Dr. Francisco M. Abarca-Rendon ).

Mixed Acinar Neuroendocrine Carcinoma of the Pancreas: Comparative Population-Based Epidemiology of a Rare and Fatal Malignancy in The United States

Mixed acinar neuroendocrine carcinoma of the pancreas (MANEC-P) is an extremely rare malignancy with a poor prognosis. However, epidemiological estimates of MANEC-P remain unknown. This study aimed to estimate and compare the incidence, prevalence, and cancer-specific survival (CSS) of MANEC-P in the United States (US). Patients with MANEC-P were identified through the Surveillance, Epidemiology, and End Results (SEER) and National Program of Cancer Registries databases between 2000-2017. The primary outcomes included age-adjusted incidence rate, limited-duration prevalence, and CSS. A total of 630 patients were identified for the incidence analysis and 149 for the prevalence and CSS analyses. The MANEC-P incidence rate was 0.011 per 100,000 individuals, which was the lowest among pancreatic cancer histologic subtypes. The incidence rate was significantly higher in men and Black races and peaked at 75-79 years of age. The incidence rate was the lowest in the midwestern region (0.009) and the highest in the northeastern US (0.013). The 17-year prevalence was 0.00005%, indicating that 189 patients were alive in the United States at the beginning of 2018. The median CSS of MANEC-P was estimated to be 41 (23, 69) months. In conclusion, MANEC-P is very rare, and its incidence rate has been steady in the US over the last two decades. MANEC-P has a poor prognosis and is the 5th leading cause of pancreatic cancer-related death in the US.

Modulating sphingosine 1-phosphate receptor signaling skews intrahepatic leukocytes and attenuates murine nonalcoholic steatohepatitis

Sphingosine 1-phosphate (S1P) is a bioactive sphingolipid associated with nonalcoholic steatohepatitis (NASH). Immune cell-driven inflammation is a key determinant of NASH progression. Macrophages, monocytes, NK cells, T cells, NKT cells, and B cells variably express S1P receptors from a repertoire of 5 receptors termed S1P₁ - S1P₅. We have previously demonstrated that non-specific S1P receptor antagonism ameliorates NASH and attenuates hepatic macrophage accumulation. However, the effect of S1P receptor antagonism on additional immune cell populations in NASH remains unknown. We hypothesized that S1P receptor specific modulation may ameliorate NASH by altering leukocyte recruitment. A murine NASH model was established by dietary feeding of C57BL/6 male mice with a diet high in fructose, saturated fat, and cholesterol (FFC) for 24 weeks. In the last 4 weeks of dietary feeding, the mice received the S1P_1,4,5 modulator Etrasimod or the S1P₁ modulator Amiselimod, daily by oral gavage. Liver injury and inflammation were determined by histological and gene expression analyses. Intrahepatic leukocyte populations were analyzed by flow cytometry, immunohistochemistry, and mRNA expression. Alanine aminotransferase, a sensitive circulating marker for liver injury, was reduced in response to Etrasimod and Amiselimod treatment. Liver histology showed a reduction in inflammatory foci in Etrasimod-treated mice. Etrasimod treatment substantially altered the intrahepatic leukocyte populations through a reduction in the frequency of T cells, B cells, and NKT cells and a proportional increase in CD11b⁺ myeloid cells, polymorphonuclear cells, and double negative T cells in FFC-fed and control standard chow diet (CD)-fed mice. In contrast, FFC-fed Amiselimod-treated mice showed no changes in the frequencies of intrahepatic leukocytes. Consistent with the improvement in liver injury and inflammation, hepatic macrophage accumulation and the gene expression of proinflammatory markers such as Lgals3 and Mcp-1 were decreased in Etrasimod-treated FFC-fed mice. Etrasimod treated mouse livers demonstrated an increase in non-inflammatory (Marco) and lipid associated (Trem2) macrophage markers. Thus, S1P_1,4,5 modulation by Etrasimod is more effective than S1P₁ antagonism by Amiselimod, at the dose tested, in ameliorating NASH, likely due to the alteration of leukocyte trafficking and recruitment. Etrasimod treatment results in a substantial attenuation of liver injury and inflammation in murine NASH.

Alternative lengthening of telomeres in primary hepatic neoplasms

The alternative lengthening of telomeres (ALT) phenotype is characterized by ultra-bright telomeres on fluorescence in situ hybridization (FISH) and is a marker of a unique mechanism of telomere maintenance in tumors. ALT does not occur in normal tissues. ALT has been described in hepatocellular carcinoma (5-10%) and in primary hepatic angiosarcomas (75%). To study the frequency of ALT in other primary hepatic tumors, a wide range of primary hepatic neoplasms were retrieved. The tumors included the following: intrahepatic and hilar cholangiocarcinomas (N = 110), hepatic adenomas (N = 35), hepatocellular carcinomas (N = 30), fibrolamellar carcinomas (n = 11), combined cholangiocarcinoma-hepatocellular carcinomas (N = 8), carcinosarcoma (N = 10), hepatoblastomas (N = 5), hemangiomas (N = 4), angiosarcomas (N = 8), epithelioid hemangioendotheliomas (N = 10), calcified nested stromal epithelial tumor (N = 2), embryonal sarcoma (N = 2), rhabdoid tumor (N = 1), bile duct adenoma (N = 1), and angiomyolipoma (N = 1). For epithelial tumors, ALT-FISH was positive in one carcinosarcoma (10% of cases), one cholangiocarcinoma (1% of cases), and one combined hepatocellular carcinoma-cholangiocarcinoma (13% of cases). In the hepatocellular carcinoma component of both the carcinosarcoma and the combined hepatocellular carcinoma-cholangiocarcinoma, the tumor cells showed patchy marked nuclear pleomorphism akin to that described previously for chromophobe hepatocellular carcinoma, which are typically ALT FISH positive. The ALT-positive cholangiocarcinoma also showed patchy, striking nuclear pleomorphism. For soft tissue tumors, ALT was positive in two angiosarcomas (N = 2; 25% of cases). In summary, this study shows that ALT-FISH is positive in rare carcinosarcomas, cholangiocarcinomas, and combined cholangiocarcinoma-hepatocellular carcinoma. ALT is not a significant mechanism of telomere maintenance in hepatocellular adenomas or fibrolamellar carcinomas and was negative in all other tested primary hepatic neoplasms. ALT-FISH is also positive in a subset of primary hepatic angiosarcomas.

Cystic lesions of the retrorectal space

Cysts of the retrorectal space comprise a heterogeneous group of rare lesions. Most develop from embryological remnants and include tailgut cysts, dermoid cysts, rectal duplication cysts, anal canal duplication cysts, sacrococcygeal teratomas and anterior meningocoele. Tailgut cyst is the most common cyst of developmental origin, usually presenting as a multilocular cystic mass with mucoid content and lined by multiple epithelial types. Compared with tailgut cysts, rectal duplication cysts display all layers of the large bowel wall including a well-defined muscularis propria. Retrorectal cysts of non-developmental origin are far less common and represent lesions that either infrequently involve the retrorectal space or undergo extensive cystic change. This review provides an overview of the various histological types of cystic lesions of the retrorectal space, divided into cysts of developmental origin and those of non-developmental origin. A practical pathological and multidisciplinary approach to diagnosing these lesions is presented.

GLI1 -Rearranged Enteric Tumor : Expanding the Spectrum of Gastrointestinal Neoplasms With GLI1 Gene Fusions

GLI1 encodes a transcription factor that targets cell cycle regulators affecting stem cell proliferation. GLI1 gene fusions were initially described in pericytomas with a t[7;12] translocation and more recently in gastric plexiform fibromyxomas and gastroblastomas. This study describes the clinicopathologic, immunohistochemical, and molecular features of three intestinal-based neoplasms harboring GLI1 gene fusions. We studied three unique mesenchymal small bowel tumors. Paraffin embedded tumor tissues from these cases and 62 additional tumor samples that included a plexiform fibromyxoma were sequenced using a targeted RNAseq method to detect fusion events. The study patients included two women and one man who were 52, 80, and 22 years of age at the time of diagnosis. The tumors involved the submucosa and muscularis propria of the duodenum, jejunum, and ileum. All 3 tumors contained a proliferation of monotonous oval or spindle cells with scattered, somewhat dilated vessels. Two cases showed epithelioid structures such as glands, tubules, or nests. Immunohistochemical analysis revealed cytokeratin expression in the epithelioid components of both tumors displaying these features, and variable numbers of mesenchymal cells. Diffuse CD56 positivity was seen in the mesenchymal component of 2 tumors and desmin and smooth muscle actin staining in the other tumor. Immunostains for S-100 protein, DOG-1, and CD117 were negative in all cases. GLI1 fusions with different partner genes were detected in all tumors, and in the plexiform fibromyxoma, used as a control. Validation by fluorescence in situ hybridization was performed. None of the tumors have recurred or metastasize after surgery. We describe novel GLI1 fusions in 3 mesenchymal neoplasms of the small intestine, including 2 with biphenotypic features. Thus far, all cases have pursued indolent clinical courses. We propose the term " GLI1 -rearranged enteric tumor" to encompass this group of unique neoplasms of the small intestine that harbor GLI1 gene fusions and expand the spectrum of gastrointestinal neoplasms with these alterations.

Culture media composition influences patient-derived organoid ability to predict therapeutic responses in gastrointestinal cancers

BACKGROUNDA patient-derived organoid (PDO) platform may serve as a promising tool for translational cancer research. In this study, we evaluated PDO's ability to predict clinical response to gastrointestinal (GI) cancers.METHODSWe generated PDOs from primary and metastatic lesions of patients with GI cancers, including pancreatic ductal adenocarcinoma, colorectal adenocarcinoma, and cholangiocarcinoma. We compared PDO response with the observed clinical response for donor patients to the same treatments.RESULTSWe report an approximately 80% concordance rate between PDO and donor tumor response. Importantly, we found a profound influence of culture media on PDO phenotype, where we showed a significant difference in response to standard-of-care chemotherapies, distinct morphologies, and transcriptomes between media within the same PDO cultures.CONCLUSIONWhile we demonstrate a high concordance rate between donor tumor and PDO, these studies also showed the important role of culture media when using PDOs to inform treatment selection and predict response across a spectrum of GI cancers.TRIAL REGISTRATIONNot applicable.FUNDINGThe Joan F. & Richard A. Abdoo Family Fund in Colorectal Cancer Research, GI Cancer program of the Mayo Clinic Cancer Center, Mayo Clinic SPORE in Pancreatic Cancer, Center of Individualized Medicine (Mayo Clinic), Department of Laboratory Medicine and Pathology (Mayo Clinic), Incyte Pharmaceuticals and Mayo Clinic Hepatobiliary SPORE, University of Minnesota-Mayo Clinic Partnership, and the Early Therapeutic program (Department of Oncology, Mayo Clinic).

Establishment and Characterization of a New Human Intrahepatic Cholangiocarcinoma Cell Line LIV27

Cholangiocarcinoma (CCA) is a highly lethal cancer arising from the biliary tract epithelium. The cancer biology of this neoplasm is not well understood. To date, only a few CCA cell lines have been reported, which were mostly developed from Asian patients. In this study, we report and characterize a new intrahepatic CCA cell line, LIV27, derived from a surgically resected tumor in a 67-year-old Caucasian woman with primary sclerosing cholangitis (PSC). LIV27 cells grow well in collagen-coated flasks or plates with a doubling time of 57.8 h at passage 14. LIV27 cells have high tumorigenicity in nude mice and stain positive for CK7 and CK19, markers that differentiate CCA from hepatocellular carcinoma. Karyotype analysis showed that LIV27 is aneuploid. We established a single-locus short tandem repeat profile for the LIV27 cell line. This newly established cell line will be a useful model for studying the molecular pathogenesis of, and developing novel therapies for, cholangiocarcinoma.

Transcriptomic Analysis of Cirrhosis-Like Hepatocellular Carcinoma Reveals Distinct Molecular Characteristics and Pathologic Staging Implications

OBJECTIVES

Cirrhosis-like hepatocellular carcinoma (CL-HCC) is a rare hepatocellular malignancy characterized by multiple tumor nodules that clinically, radiologically, macroscopically, and microscopically mimic cirrhosis. We aimed to elucidate the molecular biology of CL-HCC and determine tumor nodule clonality.

METHODS

We performed RNA sequencing on formalin-fixed, paraffin-embedded tissue from confirmed CL-HCC cases (n = 6), along with corresponding nonneoplastic hepatic tissue (n = 4) when available. Transcriptomes from our previous work on steatohepatitic hepatocellular carcinoma and The Cancer Genome Atlas (TCGA) were used for comparison purposes.

RESULTS

Histologically, CL-HCC displayed innumerable nodules and extensive vascular invasion. Intratumoral nodule comparison indicated that the multiple nodules were all clonally related, not independent primaries. The unique histomorphologic appearance corresponded with a distinct transcriptome compared with other HCCs, including fibrolamellar HCC (n = 6), steatohepatitic HCC (n = 8), and conventional HCC in TCGA (n = 424). Tumor-normal gene expression analysis revealed consistent overexpression of several genes involved in degradation of tissue matrix. No recurrent translocations or point mutations were identified. CL-HCC showed a gene expression profile indicative of zone 2 hepatocytes.

CONCLUSIONS

CL-HCC's distinctive clinicopathologic features correspond to a unique gene expression profile, increased expression of invasive markers, features of zone 2 hepatocytes, and features suggestive of intratumoral nodule monoclonality.

Impact of FGFR2 gene fusions on survival of patients with intrahepatic cholangiocarcinoma following curative intent resection

BACKGROUND

Intrahepatic Cholangiocarcinoma (iCCA) is an aggressive cancer with diverse mutational profiles. An important molecular subtype is fibroblast growth factor receptor 2 (FGFR2) fusion. The effect of FGFR2 fusions on prognosis is unknown. Our aim was to assess the outcomes in resected CCA patients in relation to FGFR2 status.

METHODS

Surgically treated CCA patients from a single institution were retrospectively reviewed between 2008 and 2014. FGFR rearrangements were detected by fluorescence in situ hybridization (FISH). Data included patient demographics, tumor pathology, disease-free survival (DFS) and overall survival (OS).

RESULTS

Ninety-five patients underwent surgical resection for iCCA. Twelve (13%) of these were found to have FGFR2 fusion, none of which were treated with FGFR targeted therapy. Patients with FGFR2 fusions were found to have a longer 5-year (83 vs. 32%, p = 0.01) and 10-year (46 vs. 22%, p = 0.04) OS. Five and 10-year DFS was also increased (68 vs. 33% p = 0.04) and (68 vs. 25 %, p = 0.02,). FGFR2 fusion status was the strongest independent factor associated with improved OS (HR 0.23, 0.09-0.62, p=0.003) and DFS (HR 0.18, 0.05-0.67, p=0.01).

CONCLUSION

Patients with CCA FGFR2 fusion have improved OS and DFS following surgical resection.

Tissue methylated DNA markers for sporadic pancreatic cancer are strongly associated with familial and genetically predisposed pancreatic cancer

High-risk individuals (HRIs) with familial and genetic predisposition to pancreatic ductal adenocarcinoma (PDAC) are eligible for screening. There is no accurate biomarker for detecting early-stage PDAC. We previously demonstrated that a panel of methylated DNA markers (MDMs) accurately detect sporadic PDAC. In this study we compared the distribution of MDMs in DNA extracted from tissue of PDAC cases who carry germline mutations and non-carriers with family history, with control tissue and demonstrate high discrimination like that seen in sporadic PDAC. These results provide scientific rationale for examining plasma MDMs in HRIs with the goal of developing a minimally-invasive early detection test.

FDG-PET Predicts Neoadjuvant Therapy Response and Survival in Borderline Resectable/Locally Advanced Pancreatic Adenocarcinoma

BACKGROUND

Neoadjuvant therapy (NAT) is used in borderline resectable/locally advanced (BR/LA) pancreatic ductal adenocarcinoma (PDAC). Anatomic imaging (CT/MRI) poorly predicts response, and biochemical (CA 19-9) markers are not useful (nonsecretors/nonelevated) in many patients. Pathologic response highly predicts survival post-NAT, but is only known postoperatively. Because metabolic imaging (FDG-PET) reveals primary tumor viability, this study aimed to evaluate our experience with preoperative FDG-PET in patients with BR/LA PDAC in predicting NAT response and survival.

METHODS

We reviewed all patients with resected BR/LA PDAC who underwent NAT with FDG-PET within 60 days of resection. Pre- and post-NAT metabolic (FDG-PET) and biochemical (CA 19-9) responses were dichotomized in addition to pathologic responses. We compared post-NAT metabolic and biochemical responses as preoperative predictors of pathologic responses and recurrence-free survival (RFS) and overall survival (OS).

RESULTS

We identified 202 eligible patients. Post-NAT, 58% of patients had optimization of CA 19-9 levels. Major metabolic and pathologic responses were present in 51% and 38% of patients, respectively. Median RFS and OS times were 21 and 48.7 months, respectively. Metabolic response was superior to biochemical response in predicting pathologic response (area under the curve, 0.86 vs 0.75; P&lt;.001). Metabolic response was the only univariate preoperative predictor of OS (odds ratio, 0.25; 95% CI, 0.13-0.40), and was highly correlated (P=.001) with pathologic response as opposed to biochemical response alone. After multivariate adjustment, metabolic response was the single largest independent preoperative predictor (P&lt;.001) for pathologic response (odds ratio, 43.2; 95% CI, 16.9-153.2), RFS (hazard ratio, 0.37; 95% CI, 0.2-0.6), and OS (hazard ratio, 0.21; 95% CI, 0.1-0.4).

CONCLUSIONS

Among patients with post-NAT resected BR/LA PDAC, FDG-PET highly predicts pathologic response and survival, superior to biochemical responses alone. Given the poor ability of anatomic imaging or biochemical markers to assess NAT responses in these patients, FDG-PET is a preoperative metric of NAT efficacy, thereby allowing potential therapeutic alterations and surgical treatment decisions. We suggest that FDG-PET should be an adjunct and recommended modality during the NAT phase of care for these patients.

BRAF Rearrangements and BRAF V600E Mutations Are Seen in a Subset of Pancreatic Carcinomas With Acinar Differentiation

CONTEXT.—

Comprehensive genomic profiling has demonstrated that approximately 20% of pancreatic carcinomas with acinar differentiation harbor potentially targetable BRAF fusions that activate the MAPK pathway.

OBJECTIVES.—

To validate the above finding by BRAF break-apart fluorescence in situ hybridization (FISH) in a large series of pure acinar cell carcinomas (ACCs), evaluate tumors for the presence of BRAF V600E mutations, and compare clinicopathologic features of tumors with BRAF rearrangements with those without.

DESIGN.—

Thirty cases of pure ACC and 6 cases of mixed acinar-neuroendocrine carcinoma (ACC-NEC) were retrieved. A break-apart FISH probe was used to detect BRAF rearrangements. Immunohistochemistry for BRAF V600E was performed.

RESULTS.—

BRAF rearrangements by FISH were found in 6 of 36 cases (17%), 5 of which were pure ACC and 1 was a mixed ACC-NEC. Follow-up was available in 29 of 36 cases (81%). The median survival was 22 months for BRAF-rearranged cases and 16 months for BRAF-intact cases; the 2-year overall survival was 50% for BRAF-rearranged cases and 35% for BRAF-intact cases. No significant clinicopathologic differences were identified in cases with BRAF rearrangement compared with those without BRAF rearrangement. BRAF V600E mutation was identified in 2 of 34 cases (6%), both of which were pure ACC and were BRAF-intact by FISH.

CONCLUSIONS.—

This study supports the finding that BRAF rearrangements are present in approximately 20% of cases and identified BRAF V600E mutations in approximately 5% of cases. These cases may benefit from targeted therapy.

Metallothionein immunohistochemistry has high sensitivity and specificity for detection of Wilson disease

Diagnosis of Wilson disease (WD) can be difficult because of its protean clinical presentations, but early diagnosis is important because effective treatment is available and can prevent disease progression. Similarly, diagnosis of WD on liver biopsy specimens is difficult due to the wide range of histologic appearances. A stain that could help identify WD patients would be of great value. The goal of this study was to use mass spectrometry-based proteomics to identify potential proteins that are differentially expressed in WD compared to controls, and could serve as potential immunohistochemical markers for screening. Several proteins were differentially expressed in WD and immunohistochemical stains for two (metallothionein (MT) and cytochrome C oxidase copper chaperone (COX17)) were tested and compared to other methods of diagnosis in WD including copper staining and quantitative copper assays. We found diffuse metallothionein immunoreactivity in all liver specimens from patients with WD (n = 20); the intensity of the staining was moderate to strong. This staining pattern was distinct from that seen in specimens from the control groups (none of which showed strong, diffuse staining), which included diseases that may be in the clinical or histologic differential of WD (steatohepatitis (n = 51), chronic viral hepatitis (n = 40), autoimmune hepatitis (n = 50), chronic biliary tract disease (n = 42), and normal liver (n = 20)). COX17 immunostain showed no significant difference in expression between the WD and control groups. MT had higher sensitivity than rhodanine for diagnosis of WD. While the quantitative liver copper assays also had high sensitivity, they require more tissue, have a higher cost, longer turnaround time, and are less widely available than an immunohistochemical stain. We conclude that MT IHC is a sensitive immunohistochemical stain for the diagnosis of WD that could be widely deployed as a screening tool for liver biopsies in which WD is in the clinical or histologic differential diagnosis.

Outcomes of pancreatectomy with portomesenteric venous resection and reconstruction for locally advanced pancreatic neuroendocrine neoplasms

BACKGROUND

While pancreatectomy with portomesenteric venous resection and reconstruction is commonly performed for locally advanced pancreatic adenocarcinoma, little is known regarding outcomes for pancreatic neuroendocrine neoplasms (panNENs).

METHODS

Patients who underwent non-parenchyma-sparing pancreatectomy for panNENs at Mayo Clinic from 2000 to 2020 were retrospectively reviewed. Propensity score matching was performed and patient characteristics and outcomes compared.

RESULTS

Of 867 eligible patients, 41 (4.7%) required vascular resection, including 38 patients who underwent portomesenteric venous resection only. Of these, 23 underwent pancreaticoduodenectomy or total pancreatectomy and 15 distal pancreatectomy. Patients who required portomesenteric venous resection had larger tumors, higher tumor grade, and higher disease stage. After propensity score matching to patients undergoing standard resection, the portomesenteric venous resection group had longer operative times, greater blood loss, and higher transfusion rates. While portomesenteric venous thrombosis was more common after venous resection, major complication rates and perioperative mortality were similar between the two groups, as were 5-year overall and progression-free survival.

CONCLUSION

For patients with locally advanced panNENs, pancreatectomy with portomesenteric venous resection and reconstruction can be performed in selected patients at high-volume centers with acceptable perioperative morbidity and short- and long-term survival.