Programmed cell death ligand 1 cut-point is associated with reduced disease specific survival in resected pancreatic ductal adenocarcinoma

Background

Programmed cell death 1 (PD1) inhibitors have recently shown promising anti-cancer effects in a number of solid tumor types. A predictive biomarker to this class of drugs has not been clearly identified; however, overexpression of the PD1 ligand (PD-L1) has shown particular promise in lung adenocarcinoma. In this study, we explore the staining characteristics, prevalence, and clinico-molecular correlates of PD-L1 overexpression in pancreatic ductal adenocarcinoma (PDAC).

Methods

A tissue microarray (TMA) was constructed from cases of resected PDAC. PD-L1 immunohistochemistry (IHC) was performed using the SP142 primary antibody. Immunohistochemical assessment for deficient mismatch repair status (MMRd), CD3 and CD8 were performed. All biomarkers were assessed independently by two anatomical pathologists and consensus achieved on all cases. Survival analysis was performed using three thresholds (> = 1%, >5% and >10%) for tumor cell membrane staining.

Results

Two-hundred fifty-two cases were included in the TMA and evaluable by IHC. Thirty-one (12%), 17 (7%), 12(5%) cases were positive at percentage cut offs of >0, >5, and >10% respectively. Increased PD-L1 expression was associated with inferior prognosis (p = 0.0367). No statistically significant association was identified between PD-L1 status and MMR status or tumor infiltrating lymphocytes.

Conclusions

This data suggests that there is an inverse relationship between PD-L1 expression and disease specific survival times in resected PDAC. Consequently, this association may represent a phenotype where increased PD-L1 expression has an effect on tumor biology and could therefore identify a subgroup where PD1 blockade could have enhanced effectiveness.

A predictive analysis of the SP120 and 10D7G2 antibodies for human equilibrative nucleoside transporter 1 (hENT1) in pancreatic ductal adenocarcinoma treated with adjuvant gemcitabine

Expression of human equilibrative nucleoside transporter 1 (hENT1) in pancreatic ductal adenocarcinoma (PDAC) has been postulated to be a marker of sensitivity to gemcitabine. However, heterogeneity in the studies attempting to quantify hENT1 expression in patients with PDAC treated with gemcitabine has yielded inconclusive results that impede the adoption of hENT1 expression as a predictive biomarker. Tissue microarrays consisting of PDAC specimens from 227 patients acquired between 1987 and 2013 annotated with treatment and outcome information were subjected to staining with two antibodies for hENT1 (10D7G2 and SP120) on a single automated platform and scored by two independent pathologists blinded to treatment and outcome. The resultant scores were subjected to individual predictive disease-specific survival analysis and to unsupervised hierarchical clustering to generate a multi-marker classification. Tumour cell staining prevalence using either SP120 or 10D7G2 was predictive of gemcitabine sensitivity (p = 0.02; p = 0.01). When combined, three groups emerged, classified as SP120_Low_10D7G2_Low, SP120_Low_10D7G2_High, and SP120_High_10D7G2_High, in which adjuvant gemcitabine conferred median survival differences of 0.2, 0.8, and 1.5 (p = 0.76, p = 0.06, p = 0.01) years, respectively. These results were largely replicated in multivariable analysis with the P value for the SP120_Low_10D7G2_High cluster achieving statistical significance (p = 0.03). These data suggest that either antibody for hENT1 can be used to predict gemcitabine sensitivity in resected PDAC. However, using both antibodies adds valuable information that enables the stratification of patients who can expect to have a good, intermediate, and poor response to adjuvant gemcitabine.

Inactivation of the Kinase Domain of CDK10 Prevents Tumor Growth in a Preclinical Model of Colorectal Cancer, and Is Accompanied by Downregulation of Bcl-2

Cyclin-dependent kinase 10 (CDK10), a CDC2-related kinase, is highly expressed in colorectal cancer. Its role in the pathogenesis of colorectal cancer is unknown. This study examines the function of CDK10 in colorectal cancer, and demonstrates its role in suppressing apoptosis and in promoting tumor growth in vitro and in vivo Modulation of CDK10 expression in colorectal cancer cell lines demonstrates that CDK10 promotes cell growth, reduces chemosensitivity and inhibits apoptosis by upregulating the expression of Bcl-2. This effect appears to depend on its kinase activity, as kinase-defective mutant colorectal cancer cell lines have an exaggerated apoptotic response and reduced proliferative capacity. In vivo, inhibiting CDK10 in colorectal cancer following intratumoral injections of lentivirus-mediated CDK10 siRNA in a patient-derived xenograft mouse model demonstrated its efficacy in suppressing tumor growth. Furthermore, using a tissue microarray of human colorectal cancer tissues, the potential for CDK10 to be a prognostic biomarker in colorectal cancer was explored. In tumors of individuals with colorectal cancer, high expression of CDK10 correlates with earlier relapse and shorter overall survival. The findings of this study indicate that CDK10 plays a role in the pathogenesis in colorectal cancer and may be a potential therapeutic target for treatment. Mol Cancer Ther; 16(10); 2292-303. ©2017 AACR.

Quality of life and satisfaction with care in a contemporary cohort of pancreatic cancer patients

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Background: Pancreatic cancer patients face significant disease- and treatment-related morbidity while management is frequently complex. With recent advances in radiation and surgery and the introduction of new systemic therapy regimens, understanding these patients’ quality of life (QOL) and their satisfaction with the care that they currently receive is essential to inform the design of future care delivery models. Methods: Pancreas Centre BC was established in British Columbia in 2012 to promote efficient triage, rapid access to multidisciplinary care, and early involvement of palliative care, if necessary. Consecutive pancreatic cancer patients who were referred to and seen at Pancreas Centre BC completed the EORTC-QLQ C30 and PAN26 questionnaires before and after surgery as well as surveys focused on the levels of satisfaction with their disease management. Using independent samples t-tests, we correlated clinical characteristics with QOL and satisfaction scores. Results: In total, 167 patients were included: median age was 63 years, 45% were men, and 70% were ECOG 0/1. The majority had early stage disease (78%), pancreatic head tumors (53%), adenocarcinoma histology (68%), and adjuvant gemcitabine (75%). Baseline mean QOL scores were 63, 90, 83, 58 and 92 (out of 100) in the overall, physical, emotional, cognitive and social domains, respectively. Advanced age ( > 70 years), weight loss ( > 10 kg), and poor ECOG were independently associated with lower overall QOL rating (all p > 0.05). Surgery had a positive impact on all functional domains where we observed a mean improvement in QOL scores ranging from 8 to 17 points (all p > 0.05). In terms of satisfaction, 94% of patients rated their overall care as good to excellent. Likewise, 80% of patients were very or mostly satisfied with the amount of information they received and 84% of patients rated the healthcare information they received as very or mostly helpful. Conclusions: Despite the morbidity of pancreatic cancer, patients referred to and seen at a tertiary pancreatic cancer center reported good QOL and satisfaction levels, suggesting that the centralization of pancreatic cancer care may be an effective model to address the high priority needs of this population

Multivariate assessment of SPARC expression in resected pancreatic ductal adenocarcinoma to identify subgroups that are sensitive to adjuvant gemcitabine

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Background: Secreted Protein, Acid, Cysteine-Rich (SPARC) has recently been postulated as a therapeutic target in pancreatic ductal adenocarcinoma (PDAC). The clinical trial findings investigating SPARC expression and nab-paclitaxel sensitivity have been discordant. This study aims to develop an integrated component based approach to the quantification of SPARC in PDAC to identify discrete predictive subgroups in a cohort of resected patients treated with an gemcitabine (GEM) or subjected to post-surgical observation. Methods: Immunohistochemical quantification of SPARC was performed on the epithelial and stromal compartments of resected PDAC on 219 patient samples on a tissue-microarray. The staining was assessed by the generation of H-Scores. The resultant scores were subjected to unsupervised hierarchical clustering. The maximum number of clusters was determined through an a priori decision that no cluster could be composed of less than 15% of the cohort. Univariable disease specific survival (DSS) analysis was performed with the Kaplan-Meier method to examine the cluster specific survival profiles with regard to gemcitabine sensitivity. Results: Mean age was 67 [38-88] with 56% being male. Most of the cohort had advanced disease with pT3 = 95% and pN1 = 72%. Lymphovascular and perinueural invasion were found in 58% and 93% of the cohort respectively. Clusters ranging in size from 35 to 76 cases were derived and represented the four-biomarker combinations of Low/Low, Low/High, High/High, and High/Low for the epithelial and stromal components respectively. None of the clinico-pathologic variables were significantly enriched in the clusters. Assessment of the predictive ability of the 4 clusters demonstrated that only one cluster (High/High) representing 76 (35%) patients in this cohort was sensitive to adjuvant GEM (p = 0.0067). Conclusions: This study shows that there is enhanced value in a combinatorial approach to the examination of SPARC in the stromal and epithelial components of PDAC where we have discovered that co-expression in both the epithelial and stromal components is significantly associated with sensitivity to adjuvant GEM.

Identification of recurrent mutational events in anorectal melanoma

Anorectal melanoma is a rare disease that carries a poor prognosis. To date, limited genetic analyses confirmed KIT mutations as a recurrent genetic event similar to other mucosal melanomas, occurring in up to 30% of anorectal melanomas. Importantly, a subset of tumors harboring activating KIT mutations have been found to respond to c-Kit inhibitor-based therapy, with improved patient survival at advanced tumor stages. We performed comprehensive targeted exon sequencing analysis of 467 cancer-related genes in a larger series of 15 anorectal melanomas, focusing on potentially actionable variants based on gain- and loss-of-function mutations. We report the identification of oncogenic driver events in the majority (93%) of anorectal melanomas. These included variants in canonical MAPK pathway effectors rarely observed in cutaneous melanomas (including an HRAS mutation, as well as a BRAF mutation resulting in duplication of threonine 599), and recurrent mutations in the tumor suppressor NF1 in 20% of cases, which represented the second-most frequently mutated gene after KIT in our series. Furthermore, we identify SF3B1 mutations as a recurrent genetic event in mucosal melanomas. Our findings provide an insight into the genetic diversity of anorectal melanomas, and suggest significant potential for alternative targeted therapeutics in addition to c-Kit inhibitors for this melanoma subtype.

In-depth mutational analyses of colorectal neuroendocrine carcinomas with adenoma or adenocarcinoma components

Neuroendocrine carcinomas (NECs) of the colorectum are rare but highly aggressive neoplasms. These tumors show some shared genetic alterations with colorectal adenocarcinomas, and most of them have adjacent glandular adenoma or adenocarcinoma components. However, genetic data on colorectal NECs still are sparse and insufficient for definite conclusions regarding their molecular origin. Based on morphological characterization, panel and whole-exome sequencing, we here present results from an in-depth analysis of a collection of 15 colorectal NECs with glandular components, 10 of which by definition were mixed adenoneuroendocrine carcinomas (MANECs). Among shared genetic alterations of both tumor components, we most frequently found TP53, KRAS and APC mutations that also had highest allele frequencies. Mutations exclusive to glandular or neuroendocrine components outnumbered shared mutations but occurred at lower allele frequencies. Our findings not only provide additional evidence for a common clonal origin of colorectal NECs and adjacent glandular tumor components, but strongly suggest their development through the classical adenoma-carcinoma sequence. Moreover, our data imply early separation of glandular and neuroendocrine components during malignant transformation with subsequent independent mutational evolution.

Personalized oncogenomics in the management of gastrointestinal carcinomas-early experiences from a pilot study

BACKGROUND

Gastrointestinal carcinomas are genomically complex cancers that are lethal in the metastatic setting. Whole-genome and transcriptome sequencing allow for the simultaneous characterization of multiple oncogenic pathways.

METHODS

We report 3 cases of metastatic gastrointestinal carcinoma in patients enrolled in the Personalized Onco-Genomics program at the BC Cancer Agency. Real-time genomic profiling was combined with clinical expertise to diagnose a carcinoma of unknown primary, to explore treatment response to bevacizumab in a colorectal cancer, and to characterize an appendiceal adenocarcinoma.

RESULTS

In the first case, genomic profiling revealed an IDH1 somatic mutation, supporting the diagnosis of cholangiocarcinoma in a malignancy of unknown origin, and further guided therapy by identifying epidermal growth factor receptor amplification. In the second case, a BRAF V600E mutation and wild-type KRAS profile justified the use of targeted therapies to treat a colonic adenocarcinoma. The third case was an appendiceal adenocarcinoma defined by a p53 inactivation; Ras/raf/mek, Akt/mtor, Wnt, and notch pathway activation; and overexpression of ret, erbb2 (her2), erbb3, met, and cell cycle regulators.

SUMMARY

We show that whole-genome and transcriptome sequencing can be achieved within clinically effective timelines, yielding clinically useful and actionable information.

Abstract B87: Co-expression of GLUT1 and MCT4 is a poor prognostic marker and predicts response to adjuvant chemotherapy in PDAC

Background: Mutant KRAS stimulates glucose uptake and lactate production in pancreatic ductal adenocarcinoma (PDAC), contributing to metabolic pathway reprogramming and tumor progression. A prognostic effect for glucose transporter GLUT1 and lactate transporter MCT4 expression in PDAC has been demonstrated but it is not known if the expression of markers of glycolytic and lactate metabolism pathways is predictive of treatment response. We aimed to validate the prognostic and assess the predictive effects of GLUT1 and MCT4 protein levels in resectable PDAC.

Methods: Immunohistochemical analysis for GLUT1 and MCT4 was performed on a tissue microarray (TMA) comprising 261 resected PDAC tumors with associated clinical outcome data. The expression of GLUT1 and MCT4 in the epithelial compartment of PDAC was quantified and patient samples were scored as low (negative and weak staining) and high (moderate and strong staining) expression groups. Univariable disease-specific survival (DSS) was assessed using the Kaplan-Meier method.

Results: 70% (182) of the patients included in the TMA had high GLUT1 staining and 58% had high MCT4 staining. GLUT1high patients had reduced median DSS compared to GLUT1low patients (1.34 vs. 2.05 years, p=0.0136). Median DSS was also reduced in the MCT4high group (1.33 vs. 1.91 years in MCT4low, p=0.0153). There was a significant co-occurrence of high GLUT1 with high MCT4 expression (70%, p<0.0001). GLUT1highMCT4high patients had reduced DSS (N=124, 1.21 years, p=0.0114) compared to GLUT1lowMCT4low (N=55, 2.04 years), GLUT1lowMCT4high (N=27, 2.12 years) and GLUT1highMCT4low (N=61, 1.85 years). 31% of all patients received adjuvant single agent chemotherapy with a pyrimidine analog. Two of the combined GLUT1/MCT4 phenotypes were found to be predictive biomarkers for adjuvant chemotherapy. GLUT1lowMCT4low showed a treatment associated two year increase in median DSS (3.32 vs. 1.38 years, p=0.0020) and GLUT1highMCT4high demonstrated a treatment associated 10 month increase in median DSS (1.68 vs. 0.89 years, p=0.0071) compared to no adjuvant therapy. No significant treatment related differences were observed in either the GLUT1lowMCT4high (p=0.24) or GLUT1highMCT4low groups (p=0.95).

Conclusions: GLUT1 and MCT4 expression are poor prognostic markers in PDAC and co-expression of these biomarkers enhances this effect. Neither GLUT1 nor MCT4 were found to be of predictive relevance when considered individually. Patients with low tumor GLUT1 and MCT4 expression had the best outcomes with chemotherapy with a pyrimidine analog. Hence, immunohistochemical analysis of GLUT1 and MCT4 in resected PDAC defines patient subgroups with different survival prognosis and predicted sensitivity to pyrimidine analog chemotherapy. The combined effect of GLUT1 and MCT4 expression on PDAC outcome suggests that therapeutic agents which can alter the glycolytic/lactate pathway may have potential for increasing sensitivity to treatment.

Citation Format: Joanna M. Karasinska, Steve E. Kalloger, Hui-li Wong, Taixiang Wang, Daniel J. Renouf, David F. Schaeffer.{Authors}. Co-expression of GLUT1 and MCT4 is a poor prognostic marker and predicts response to adjuvant chemotherapy in PDAC. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B87.

Abstract B86: Novel assessment of SPARC expression by hierarchical clustering in pancreatic ductal adenocarcinoma shows distinct prognostic and predictive groups

Background: Secreted Protein, Acid, Cysteine-Rich (SPARC) has been classified as a marker of poor prognosis and has been postulated as a therapeutic target in pancreatic ductal adenocarcinoma (PDAC). The clinical trial findings have been discordant with Phase I/II trials declaring that patients treated with nab-paclitaxel and gemcitabine whose tumors express SPARC in the stromal component have a significantly improved response. Unfortunately, these results were not validated in a subsequent Phase III trial. The focus of examining SPARC expression in a particular component and using nab-paclitaxel, which binds to SPARC, sets the stage for partial clinical efficacy due to component expression heterogeneity. The goal of this study is to develop an integrated component based approach to the quantification of SPARC in PDAC to reveal discrete prognostic and predictive groups in a cohort of resected patients treated with an adjuvant pyrimidine analog or subjected to post-surgical observation.

Methods: Tissue-microarray based immunohistochemical quantification of SPARC expression was performed in the epithelial and stromal histological components of 246 resected PDACs from the Vancouver Coastal Health Region collected between 1989-2013. The semi-quantitative H-Score methodology was used where the percent of cells staining for SPARC is multiplied by the subjective assessment of its intensity (1-3) resulting in a range of scores between 0 - 300. These scores were subjected to unsupervised hierarchical clustering using Ward’s algorithm. The number of clusters was determined through an a priori decision that no cluster could have a resultant N < 30. Comparisons of component specific H-Scores across the resultant clusters were performed with the non-parametric Steel-Dwass test for multiple comparisons. Univariable disease specific survival (DSS) analysis was performed with the Kaplan-Meier method to examine the cluster specific survival profiles with regard to prognostic and predictive effects. The proportional hazards model was used to perform multivariable DSS to determine if the resultant prognostic groups were statistically independent when other known prognostic variables were considered.

Results: The distribution of H-Scores spanned the entire range of possible values for both the epithelial and stromal components with medians [IQRs] of 120 [120] and 270 [120] respectively. The two-variable hierarchical clustering procedure yielded six clusters ranging in size from 31 to 51 cases. Kaplan-Meier curves showed no statistically significant differences between any of the clusters. However, the cluster exhibiting the best prognosis (N=36) also had significantly lower H-Scores for the stromal component compared to the remaining 5 clusters (p<0.0001). Similar differences were observed for the epithelial component with statistically significant differences observed in 4 (p<=0.0008) of the 5 comparisons. Based on these data, the five clusters with higher expression and one with low were respectively categorized as SPARCHigh (N =243) and SPARCLow (N=36). Kaplan-Meier analysis showed that the SPARCLow cohort had a 7.4-month survival advantage (p=0.03). Multivariable analysis was performed including: age at surgery, adjuvant chemotherapy, lymphovascular invasion, perineural invasion, pN Stage, and tumor budding which showed that the SPARCLow/High categorization is of independent prognostic significance (p=0.03). Assessment of the predictive ability of the six SPARC clusters showed that three of the six clusters representing 117 (47%) patients in this cohort would benefit from adjuvant pyrimidine analog based therapy. The three predictive clusters had concordant high or low expression in both components.

Conclusion: This study illustrates that there is enhanced value in a combinatorial approach to the examination of SPARC in the stromal and epithelial components of PDAC where we have confirmed its status as a negative prognostic marker. While this cohort cannot address the issue of nab-paclitaxel in PDAC, we have noted that heterogeneity of SPARC expression at the component level can yield discrete predictive groups with regard to response to adjuvant pyrimidine analogs.

Citation Format: Steve E. Kalloger, Joanna M. Karasinska, HuiLi Wong, Daniel J. Renouf, David F. Schaeffer.{Authors}. Novel assessment of SPARC expression by hierarchical clustering in pancreatic ductal adenocarcinoma shows distinct prognostic and predictive groups. [abstract]. In: Proceedings of the AACR Special Conference on Pancreatic Cancer: Advances in Science and Clinical Care; 2016 May 12-15; Orlando, FL. Philadelphia (PA): AACR; Cancer Res 2016;76(24 Suppl):Abstract nr B86.

Prognostic role and implications of mutation status of tumor suppressor gene ARID1A in cancer: a systematic review and meta-analysis

Loss of the tumor suppressor gene AT-rich interactive domain-containing protein 1A (ARID1A) has been demonstrated in several cancers, but its prognostic role is unknown. We aimed to investigate the risk associated with loss of ARID1A (ARID1A−) for all-cause mortality, cancer-specific mortality and recurrence of disease in subjects with cancer. PubMed and SCOPUS search from database inception until 01/31/2015 without language restriction was conducted, contacting authors for unpublished data. Eligible were prospective studies reporting data on prognostic parameters in subjects with cancer, comparing participants with presence of ARID1A (ARID1A+) vs. ARID1A−, assessed either via immunohistochemistry (loss of expression) or with genetic testing (presence of mutation). Data were summarized using risk ratios (RR) for number of deaths/recurrences and hazard ratios (HR) for time-dependent risk related to ARID1A− adjusted for potential confounders. Of 136 hits, 25 studies with 5,651 participants (28 cohorts; ARID1A−: n = 1,701; ARID1A+: n = 3,950), with a mean follow-up period of 4.7 ± 1.8 years, were meta-analyzed. Compared to ARID1A+, ARID1A− significantly increased cancer-specific mortality (studies = 3; RR = 1.55, 95% confidence interval (CI) = 1.19–2.00, I² = 31%). Using HRs adjusted for potential confounders, ARID1A− was associated with a greater risk of cancer-specific mortality (studies = 2; HR = 2.55, 95%CI = 1.19–5.45, I² = 19%) and cancer recurrence (studies = 10; HR = 1.93, 95%CI = 1.22–3.05, I² = 76%). On the basis of these results, we have demonstrated that loss of ARID1A shortened time to cancer-specific mortality, and to recurrence of cancer when adjusting for potential confounders. For its role, this gene should be considered as an important potential target for personalized medicine in cancer treatment.

SATB2 as an Immunohistochemical Marker for Colorectal Adenocarcinoma: A Concise Review of Benefits and Pitfalls

SATB2 is part of the family of matrix attachment region–binding transcription factors, and has developmental roles in craniofacial, neural, and osteoblastic differentiation. Recently, SATB2 has been shown to be highly expressed in the epithelium of the lower gastrointestinal tract, with a relatively narrow expression profile in malignancies, including colorectal/appendiceal adenocarcinomas, tumors of osteoblastic differentiation, and renal/urothelial carcinomas. SATB2 has gained interest as a relatively specific marker of colorectal differentiation, with potential applications including determining origin of adenocarcinomas of unknown primary and distinguishing primary ovarian mucinous adenocarcinomas from colorectal metastases. Here, we briefly review the biology, expression profile, and potential histologic applications of SATB2.

Sensitivities of Biopsy Sites in the Endoscopic Evaluation of Graft-Versus-Host Disease: Retrospective Review from a Tertiary Center

BACKGROUND

Graft-versus-host disease (GVHD) is a complication of hematopoietic stem cell transplantation that frequently affects the gastrointestinal (GI) tract. The best biopsy sites to establish the diagnosis have not been clearly established.

AIMS

To determine the best sites for obtaining biopsies in evaluating GI GVHD.

METHODS

All cases of biopsy-proven GI GVHD (GVHD+) were isolated from a pathology database over a 2-year period at a single tertiary center (n = 46). Demographic, clinical, and endoscopic data were extracted. For comparison, 46 consecutive GVHD-negative cases (GVHD-) were obtained. Sensitivities in diagnosing GVHD in the upper and lower GI tract were calculated.

RESULTS

In the GVHD- group, they were commonly investigated with an esophagogastroduodenoscopy (EGD) (60 vs. 22 % in the GVHD+ group, p < 0.01), while a colonoscopy (CLN) was commonly performed in the GVHD+ group (33 vs. 12 %, p = 0.02). Among the GVHD + patients, for EGDs, the sensitivity was highest for duodenal biopsies at 89 %. For flexible sigmoidoscopies (FSs) and CLNs, the sensitivities among all sites were similar (85 % agreement, kappa 0.58, p = 0.01). There were no cases in which GVHD was diagnosed in the right side of the colon without a positive biopsy in the left side of the colon.

CONCLUSIONS

In this cohort of GI GVHD patients, duodenum biopsies produced the highest yield in diagnosing GVHD when compared to other sites of the upper GI tract. Sensitivities were similar among all sites on lower endoscopies, suggesting that a FS is sufficient for diagnosing GVHD in suspected patients with diarrhea.

Clinical utility of circulating tumor DNA (ctDNA) in resectable pancreatic ductal adenocarcinoma (PDAC)

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Background: ctDNA is emerging as a promising biomarker, with potential utility in screening, detecting minimal residual disease after curative resection and monitoring treatment response or resistance in advanced disease. Most PDAC studies to date have focused on identifying mutant KRAS ctDNA in metastatic disease. Here we perform sequential ctDNA quantification in patients (pts) with resectable PDAC using a novel and highly sensitive multiplex technology to explore the clinical utility of ctDNA as a diagnostic and prognostic biomarker. Methods: Banked plasma and tumor samples from 18 pts with resected PDAC were retrieved. Plasma samples were collected 0-28 days before, and 28-70 days after surgery. DNA was extracted using standard protocols and analyzed using the OnTarget system, which enriches for DNA molecules containing hot spot mutations prior to sequencing. A 96-plex panel that includes the most prevalent mutations in KRAS, PIK3CA and TP53 was used. Results: 16 pts (89%) had at least 1 mutation detected by OnTarget in the tumor sample, most frequently in KRAS codon 12 (n = 14). ctDNA was detected in the pre-operative blood sample in 7/16 pts with tumor mutations (sensitivity 44%) and 0/2 pts without detectable tumor mutations (specificity 100%). Of the 10 pts with available post-operative blood samples, 1 did not have a tumor mutation. 4 pts had detectable ctDNA, 3 of whom have recurred. In contrast, 0 of the 5 pts without detectable post-operative ctDNA have recurred. At median follow-up of 37 weeks, recurrence-free survival (RFS) was significantly longer in pts without detectable ctDNA after surgery (median not reached vs 9 weeks, p = 0.022). Of 11 plasma samples with detectable ctDNA, 3 harbored mutations that were not detected in the primary tumor, including 2 non-KRAS mutations (GNAS R201H and PIK3CA E542K). Conclusions: Pre-operative ctDNA has low sensitivity, suggesting limited utility in PDAC screening. RFS was significantly longer in pts without detectable post-operative ctDNA; however this analysis is limited by small numbers and short follow-up. Discordance in hot spot mutations detected in tumor and matched plasma was observed in 27% of samples, possibly related to intratumoral heterogeneity.

Comprehensive genomic analysis in metastatic pancreatic ductal adenocarcinoma (PDAC)

285

Background: In the absence of defined tumor molecular subtypes and validated predictive markers, PDAC has been largely treated as a single disease. Recent studies of molecular subtyping in PDAC reveal a complex mutational landscape with data suggesting the presence of genomic and gene expression signatures that may have prognostic and therapeutic significance. These studies predominantly focused on resected PDAC and lack data on metastatic tumors. We aim to explore the clinical utility of whole genome sequencing (WGS) and transcriptome analysis from metastatic biopsy samples in patients (pts) with advanced PDAC. Methods: Pts with incurable advanced cancers undergo tumor biopsy for in-depth WGS and RNA sequencing (RNASeq) as part of an ongoing prospective study (NCT02155621). Comprehensive bioinformatics analysis is performed to identify somatic cancer aberrations, gene expression changes and cellular pathway abnormalities. Here we describe clinical and molecular data on the subset of pts with advanced PDAC. Results: Sixteen PDAC pts have been enrolled; median age 59 years, 8 males (50%), 10 with de novo metastases (63%). Full WGS and RNASeq were completed in 11 pts (1 failed biopsy, 4 had insufficient tumor). KRAS codon 12 and TP53 mutations were present in all but one pt. CDKN2A and SMAD4 were also frequently altered (7 and 4 pts respectively). Gene expression analysis for classical and basal subtypes similar to those recently described (PMID 26343385) identified 3 and 6 pts with classical and basal expression patterns respectively, and 2 pts with mixed expression. Overall survival (OS) was significantly worse for the basal subtype vs all others (median OS 7 vs. 13.9 months (ms), p = 0.017). When separated into 3 subtypes a significant difference was still noted (median OS 7 ms in basal, 19.2 ms in classical and 11.8 ms in mixed subtype, p = 0.032). Conclusions: WGS analysis demonstrated a similar mutation pattern to that described in resectable PDAC, with no novel actionable mutations identified. Gene expression analysis demonstrated the presence of distinct gene expression signatures significantly associated with outcome, despite small pt numbers. These results need to be validated prospectively in larger cohorts. Clinical trial information: NCT02155621.

Loco-regional outcomes of a population-based cohort of rectal neuroendocrine tumors

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Background: Optimal management of rectal neuroendocrine tumors (NETs) is not well defined. We characterized the clinicopathologic features, loco-regional, and systemic management of a population-based cohort of rectal NETs. Methods: Patients diagnosed with rectal NETs from 1999-2011 were identified from British Columbia provincial databases. NETs were classified as G1 and G2 tumors with a Ki-67 ≤ 20% and/or mitotic count ≤ 20 per high power field. Results: Of 91 rectal NETs, median age was 58 (IQR 48-65) years and 35 (38%) were male. Median tumor size was 6 (IQR 4-8) mm. Median overall survival was 164.7 months, with 3 patients presenting with stage IV disease. Treatment included local excision (n = 79), surgical resection (n = 6), and pelvic radiation (n = 1; T3N1 tumor). Final margin status was positive in 17 (20%) cases. Local relapse occurred in 8 (9%) cases, and one relapse to bone 13 months after T3N1 tumor resection. Univariate analysis demonstrated an association between local relapse and T classification, Ki-67, mitotic count, grade, and perineural invasion (p< 0.01), but not N or M classification, or lymphovascular invasion. Local relapse was not associated with surgical management or margin status. Of 3 patients with metastatic disease, two received systemic management, with capecitabine and temozolomide. Conclusions: Rectal NETs generally presented with small, early tumors and were treated with local excision or surgical resection without pelvic radiation. [Table: see text]

Unusual case of drug-induced cholestasis due to glucosamine and chondroitin sulfate

Glucosamine (GS) and chondroitin sulfate (CS) are common over-the-counter (OTC) supplements used in the treatment of osteoarthritis. These medications are seemingly safe, but there are increasing reports of hepatotoxicity with these supplements. We reported a unique case of drug-induced cholestasis caused by GS and CS in a combination tablet. The etiology of the jaundice was overlooked despite extensive investigations over a three-month period. Unlike drug-induced hepatocellular injury, drug-induced cholestatic jaundice with GS and CS has only been reported twice before. This case emphasizes the importance of a complete medication history, especially OTC supplements, in the assessment of cholestasis.

Immunophenotyping of ampullary carcinomata allows for stratification of treatment specific subgroups

BACKGROUND

Ampullary carcinomata (AC) can be separated into intestinal (IT) or pancreatobiliary (PB) subtypes. Although morphological, immunohistochemical and molecular differentiation of IT and PB have been well documented; the prognostic significance of histological subtype and whether patients with either subtype benefit from differential chemotherapeutic regimens remains unclear.

METHODS

As part of a larger cohort study, patients who underwent resection for AC or pancreatic ductal adenocarcinoma (PDAC) were retrospectively identified. Clinicopathological covariates and outcome were obtained and MUC1, MUC2, CDX2 and CK20 were assessed with immunohistochemistry.

RESULTS

Of 99 ACs, the resultant immunophenotypes indicated 48% and 22% were IT and PB, respectively. Thirty (30%) cases were quadruple negative (QN). Within the PDAC cohort (N = 257), the most prevalent immunophenotype was QN (53%). Subsequently, all QN ACs were classified as PB immunohistochemically yielding 47.5% and 52.5% classified as IT and PB, respectively. Involved regional lymph nodes and elevated T-stage were significantly associated with PB compared with IT AC (p = 0.0032 and 0.0396, respectively). Progression-free survival revealed inferior survival for PB versus IT AC (p = 0.0156).

CONCLUSIONS

AC can be classified into prognostic groups with unique clinicopathological characteristics using immunohistochemistry. Immunophenotypical similarity of PB and PDAC suggests that treatment regimens similar to those used in PDAC should be explored.

Mismatch repair status may predict response to adjuvant chemotherapy in resectable pancreatic ductal adenocarcinoma

Deficiencies in DNA mismatch repair have been associated with inferior response to 5-FU in colorectal cancer. Pancreatic ductal adenocarcinoma is similarly treated with pyrimidine analogs, yet the predictive value of mismatch repair status for response to these agents has not been examined in this malignancy. A tissue microarray with associated clinical outcome, comprising 254 resected pancreatic ductal adenocarcinoma patients was stained for four mismatch repair proteins (MLH1, MSH2, MSH6 and PMS2). Mismatch repair deficiency and proficiency was determined by the absence or presence of uniform nuclear staining in tumor cells, respectively. Cases identified as mismatch repair deficient on the tissue microarray were confirmed by immunohistochemistry on whole slide sections. Of the 265 cases, 78 (29%) received adjuvant treatment with a pyrimidine analog and 41 (15%) showed a mismatch repair-deficient immunoprofile. Multivariable disease-specific survival in the mismatch repair-proficient cohort demonstrated that adjuvant chemotherapy, regional lymph-node status, gender, and the presence of tumor budding were significant independent prognostic variables (P≤0.04); however, none of the eight clinico-pathologic covariates examined in the mismatch repair-deficient cohort were of independent prognostic significance. Univariable assessment of disease-specific survival revealed an almost identical survival profile for both treated and untreated patients with a mismatch repair-deficient profile, while treatment in the mismatch repair-proficient cohort conferred a greater than 10-month median disease-specific survival advantage over their untreated counterparts (P=0.0018). In this cohort, adjuvant chemotherapy with a pyrimidine analog conferred no survival advantage to mismatch repair-deficient pancreatic ductal adenocarcinoma patients. Mismatch repair immunoprofiling is a feasible predictive marker in pancreatic ductal adenocarcinoma patients, and further prospective evaluation of this finding is warranted.

Gastrointestinal Endoscopic Ultrasound-Guided Fine-Needle Aspiration Biopsy Specimens: Adequate Diagnostic Yield and Accuracy Can Be Achieved without On-Site Evaluation

BACKGROUND

Endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNA) is the preferred method for biopsying the gastrointestinal tract, and rapid on-site cytological evaluation is considered standard practice. Our institution does not perform on-site evaluation; this study analyzes our overall diagnostic yield, accuracy, and incidence of nondiagnostic cases to determine the validity of this strategy.

DESIGN

Data encompassing clinical information, procedural records, and cytological assessment were analyzed for gastrointestinal EUS-FNA procedures (n = 85) performed at Vancouver General Hospital from January 2012 to January 2013. We compared our results with those of studies that had on-site evaluation and studies that did not have on-site evaluation.

RESULTS

Eighty-five biopsies were performed in 78 patients, from sites that included the pancreas, the stomach, the duodenum, lymph nodes, and retroperitoneal masses. Malignancies were diagnosed in 45 (53%) biopsies, while 24 (29%) encompassed benign entities. Suspicious and atypical results were recorded in 8 (9%) and 6 (7%) cases, respectively. Only 2 (2%) cases received a cytological diagnosis of 'nondiagnostic'. Our overall accuracy was 72%, our diagnostic yield was 98%, and our nondiagnostic rate was 2%. Our results did not significantly differ from those of studies that did have on-site evaluation.

CONCLUSION

Our study highlights that adequate diagnostic accuracy can be achieved without on-site evaluation.

Simplified 2-tier histologic grading system accurately predicts outcomes in goblet cell carcinoid of the appendix

Goblet cell carcinoid (GCC) is a rare appendiceal malignancy with both neuroendocrine and glandular features. Clinical outcomes of patients with GCC vary widely and a histology-based 3-tiered prognostic scheme has been previously suggested; however, this scheme is subjective and challenging to apply in day-to-day practice. We sought to construct a simplified and prognostic grading system based on objective histologic features with specific criteria. A continuous population-based cohort of GCC with clinical outcome data and archival tissue available for review was extracted from regional databases. For the 78 patients with confirmed appendiceal GCC, specific histologic features, including cytologic atypia, peritumoral stromal desmoplasia, and solid growth pattern, were recorded, and a scoring system was devised, which separates patients with GCC into low-grade (n = 55; 71%) or high-grade (n = 23; 29%) histology. Correspondingly, clinical follow-up data show good prognosis in those with low-grade histology with median and 10-year overall survival of 51.0 months and 80.5%, respectively, whereas those with high-grade histology have a poor prognosis with median and 10-year overall survival of 16.5 months (P = .006) and 0% (P < .001), respectively. Multivariate Cox proportional hazard modeling demonstrates that this 2-tier histologic system remains predictive of overall survival when controlled for TNM clinicopathological stage. These data show that a simple and objective histologic scoring system separates GCC into low- and high-grade histology with divergent clinical outcomes.

Prognostic factors and sites of metastasis in unresectable locally advanced pancreatic cancer

Due to differences in natural history and therapy, clinical trials of patients with advanced pancreatic cancer have recently been subdivided into unresectable locally advanced pancreatic cancer (LAPC) and metastatic disease. We aimed to evaluate prognostic factors in LAPC patients who were treated with first-line chemotherapy and describe patterns of disease progression. Patients with LAPC who initiated first-line palliative chemotherapy, 2001–2011 at the BC Cancer Agency were included. A retrospective chart review was conducted to identify clinicopathologic variables, treatment, and subsequent sites of metastasis. Kaplan–Meier and Cox-regression survival analyses were performed. A total of 244 patients were included in this study. For the majority of patients (94.3%), first-line therapy was single-agent gemcitabine. About 144 (59%) patients developed distant metastatic disease and the most frequent metastatic sites included peritoneum/omentum (42.3%), liver (41%), lungs (13.9%), and distant lymph nodes (9%). Median overall survival (OS) for the entire cohort was 11.7 months (95% CI, 10.6–12.8). Development of distant metastases was associated with significantly inferior survival (HR 3.56, 95% CI 2.57–4.93), as was ECOG 2/3 versus 0/1 (HR 1.69, 95% CI 1.28–2.23), CA 19.9 > 1000 versus ≤1000 (HR 1.59, 95% CI 1.19–2.14) and female gender, (HR 1.57, 95% CI 1.19–2.08). In this population-based study, 41% of LAPC patients treated with first-line chemotherapy died without evidence of distant metastases. Prognostic factors for LAPC were baseline performance status, elevated CA 19.9, gender, and development of distant metastasis. Results highlight the heterogeneity of LAPC and the importance of locoregional tumor control.

Hereditary Diffuse Gastric Cancer Syndrome: CDH1 Mutations and Beyond

IMPORTANCE

E-cadherin (CDH1) is a cancer predisposition gene mutated in families meeting clinically defined hereditary diffuse gastric cancer (HDGC). Reliable estimates of cancer risk and spectrum in germline mutation carriers are essential for management. For families without CDH1 mutations, genetic-based risk stratification has not been possible, resulting in limited clinical options.

OBJECTIVES

To derive accurate estimates of gastric and breast cancer risks in CDH1 mutation carriers and determine if germline mutations in other genes are associated with HDGC.

DESIGN, SETTING, AND PARTICIPANTS

Testing for CDH1 germline mutations was performed on 183 index cases meeting clinical criteria for HDGC. Penetrance was derived from 75 mutation-positive families from within this and other cohorts, comprising 3858 probands (353 with gastric cancer and 89 with breast cancer). Germline DNA from 144 HDGC probands lacking CDH1 mutations was screened using multiplexed targeted sequencing for 55 cancer-associated genes.

MAIN OUTCOMES AND MEASURES

Accurate estimates of gastric and breast cancer risks in CDH1 mutation carriers and the relative contribution of other cancer predisposition genes in familial gastric cancers.

RESULTS

Thirty-one distinct pathogenic CDH1 mutations (14 novel) were identified in 34 of 183 index cases (19%). By the age of 80 years, the cumulative incidence of gastric cancer was 70% (95% CI, 59%-80%) for males and 56% (95% CI, 44%-69%) for females, and the risk of breast cancer for females was 42% (95% CI, 23%-68%). In CDH1 mutation-negative index cases, candidate mutations were identified in 16 of 144 probands (11%), including mutations within genes of high and moderate penetrance: CTNNA1, BRCA2, STK11, SDHB, PRSS1, ATM, MSR1, and PALB2.

CONCLUSIONS AND RELEVANCE

This is the largest reported series of CDH1 mutation carriers, providing more precise estimates of age-associated risks of gastric and breast cancer that will improve counseling of unaffected carriers. In HDGC families lacking CDH1 mutations, testing of CTNNA1 and other tumor suppressor genes should be considered. Clinically defined HDGC families can harbor mutations in genes (ie, BRCA2) with different clinical ramifications from CDH1. Therefore, we propose that HDGC syndrome may be best defined by mutations in CDH1 and closely related genes, rather than through clinical criteria that capture families with heterogeneous susceptibility profiles.

Personalized oncogenomics: clinical experience with malignant peritoneal mesothelioma using whole genome sequencing

Peritoneal mesothelioma is a rare and sometimes lethal malignancy that presents a clinical challenge for both diagnosis and management. Recent studies have led to a better understanding of the molecular biology of peritoneal mesothelioma. Translation of the emerging data into better treatments and outcome is needed. From two patients with peritoneal mesothelioma, we derived whole genome sequences, RNA expression profiles, and targeted deep sequencing data. Molecular data were made available for translation into a clinical treatment plan. Treatment responses and outcomes were later examined in the context of molecular findings. Molecular studies presented here provide the first reported whole genome sequences of peritoneal mesothelioma. Mutations in known mesothelioma-related genes NF2, CDKN2A, LATS2, amongst others, were identified. Activation of MET-related signaling pathways was demonstrated in both cases. A hypermutated phenotype was observed in one case (434 vs. 18 single nucleotide variants) and was associated with a favourable outcome despite sarcomatoid histology and multifocal disease. This study represents the first report of whole genome analyses of peritoneal mesothelioma, a key step in the understanding and treatment of this disease.

Retrospective review using targeted deep sequencing reveals mutational differences between gastroesophageal junction and gastric carcinomas

BACKGROUND

Adenocarcinomas of both the gastroesophageal junction and stomach are molecularly complex, but differ with respect to epidemiology, etiology and survival. There are few data directly comparing the frequencies of single nucleotide mutations in cancer-related genes between the two sites. Sequencing of targeted gene panels may be useful in uncovering multiple genomic aberrations using a single test.

METHODS

DNA from 92 gastroesophageal junction and 75 gastric adenocarcinoma resection specimens was extracted from formalin-fixed paraffin-embedded tissue. Targeted deep sequencing of 46 cancer-related genes was performed through emulsion PCR followed by semiconductor-based sequencing. Gastroesophageal junction and gastric carcinomas were contrasted with respect to mutational profiles, immunohistochemistry and in situ hybridization, as well as corresponding clinicopathologic data.

RESULTS

Gastroesophageal junction carcinomas were associated with younger age, more frequent intestinal-type histology, more frequent p53 overexpression, and worse disease-free survival on multivariable analysis. Among all cases, 145 mutations were detected in 31 genes. TP53 mutations were the most common abnormality detected, and were more common in gastroesophageal junction carcinomas (42% vs. 27%, p = 0.036). Mutations in the Wnt pathway components APC and CTNNB1 were more common among gastric carcinomas (16% vs. 3%, p = 0.006), and gastric carcinomas were more likely to have ≥3 driver mutations detected (11% vs. 2%, p = 0.044). Twenty percent of cases had potentially actionable mutations identified. R132H and R132C missense mutations in the IDH1 gene were observed, and are the first reported mutations of their kind in gastric carcinoma.

CONCLUSIONS

Panel sequencing of routine pathology material can yield mutational information on several driver genes, including some for which targeted therapies are available. Differing rates of mutations and clinicopathologic differences support a distinction between adenocarcinomas that arise in the gastroesophageal junction and those that arise in the stomach proper.

Bone morphogenetic protein antagonist gremlin-1 regulates colon cancer progression

Bone morphogenetic proteins (BMP) are phylogenetically conserved signaling molecules of the transforming growth factor-beta (TGF-beta) superfamily of proteins, involved in developmental and (patho)physiological processes, including cancer. BMP signaling has been regarded as tumor-suppressive in colorectal cancer (CRC) by reducing cancer cell proliferation and invasion, and by impairing epithelial-to-mesenchymal transition (EMT). Here, we mined existing proteomic repositories to explore the expression of BMPs in CRC. We found that the BMP antagonist gremlin-1 (GREM1) is secreted from heterotypic tumor-host cell interactions. We then sought to investigate whether GREM1 is contextually and mechanistically associated with EMT in CRC. Using immunohistochemistry, we showed that GREM1-expressing stromal cells harbor prominent features of myofibroblasts (i.e., cancer-associated fibroblasts), such as expression of α-smooth muscle actin and laminin-beta-1, and were in contextual proximity to invasion fronts with loss of the tight junction protein occludin and parallel nuclear accumulation of β-catenin, two prominent EMT hallmarks. Furthermore, in vitro assays demonstrated that GREM1-dependent suppression of BMP signaling results in EMT induction, characterized by cadherin switching (loss of E-cadherin-upregulation of N-cadherin) and overexpression of Snail. Collectively, our data support that GREM1 promotes the loss of cancer cell differentiation at the cancer invasion front, a mechanism that may facilitate tumor progression.

Combined hepatocellular-cholangiocarcinoma (cHCC-CC): a distinct entity

Patients with hepatocellular carcinoma (HCC), the fifth most common cancer worldwide, display a highly variable clinical course, suggesting that HCC encompasses several biologically distinct subtypes. This heterogeneity has the potential to impede both treatment decisions and prognostic predictions for patients with HCC. One distinct, albeit rare, subtype of HCC is combined hepatocellular-cholangiocarcinoma (cHCC-CC), which overall carries a poorer prognosis than HCC and cholangiocarcinoma (CC) alone. This review discusses predominantly the histopathologic and pathogenetic intricacies of this tumor and highlights the need for an accurate diagnosis of this specific HCC subtype.

Abstract 1282: Genetic basis of hereditary gastric cancer: Beyond the CDH1 locus

Importance. Hereditary gastric cancer (HGC) is a rare, autosomal dominant susceptibility syndrome characterized either by early onset diffuse gastric cancer and lobular breast cancer or aggregates of intestinal gastric cancer. The genetic etiology of &lt;50% of families classified as hereditary diffuse gastric cancer (HDGC) can be attributed to pathogenic germline mutations in the gene CDH1 (which encodes a crucial cellular adhesion molecule, E-cadherin). Unfortunately, the genetic basis of CDH1-negative HDGC families and all familial intestinal gastric cancers is unknown.

Objectives. 1) Determine whether pathogenic germline mutations in genes related to upper gastrointestinal disorders (UGI) are causative in HGC and 2) show that a targeted multiplexed next generation sequencing approach is effective and efficient for detecting such mutations.

Methods & Participants. 115 probands from families who met clinical criteria for HDGC (n=108) or FIGC (n=7) were included. HDGC participants have all previously tested negative for CDH1 variants. A custom panel of 55 genes previously associated with heritable UGI disorders was designed through literature research and collaborative efforts. The germline DNA of probands from each family was sequenced for all targeted regions using the MiSeq platform. Candidate variants were selected based on likelihood of pathogenicity (protein truncating, rare/novel pathogenic missense variants) then validated via Sanger sequencing. Tumour materials from mutation-carriers were analyzed for loss of heterozygosity via immunohistochemistry and/or second hit analysis. When available, germline DNA of additional family members was collected for segregation analysis.

Results. We have identified clearly pathogenic mutations in unrelated HGC families, including two protein truncating mutations each in CTNNA1 and BRCA2 genes and two rare, pathogenic missense mutations each in SDHB and STK11 genes. Additional protein truncating mutations were identified in moderately penetrant genes ATM (4 families), MSR1 (2 families), and PALB2 (1 family). Overall, 13% of families included in this study were found to have pathogenic (8) or likely pathogenic (7) mutations in genes included on our custom panel. Tumour material was available from probands with truncating CTNNA1 variants, revealing distinct loss of protein expression using immunohistochmistry. This further supports the likelihood of pathogenicity.

Conclusion & Relevance. Using a targeted next generation sequencing approach that significantly reduced sequencing cost while simultaneously improving turn-around time, we show that HGC families can carry pathogenic mutations outside the CDH1-locus, including genes commonly associated with other UGI syndromes. The genetic basis of the remaining families likely lies in yet to be discovered susceptibility genes or, in the case of HDGC, additional abnormalities at the CDH1-locus.

Citation Format: Samantha Hansford, Hector LiChang, Pardeep Kaurah, Michelle Woo, Karey Shumansky, David F. Schaeffer, Giovanni Corso, George Zogopoulos, Steven Gallinger, Hugo Pinheiro, Franco Roviello, Carla Oliveira, David Huntsman. Genetic basis of hereditary gastric cancer: Beyond the CDH1 locus. [abstract]. In: Proceedings of the 105th Annual Meeting of the American Association for Cancer Research; 2014 Apr 5-9; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2014;74(19 Suppl):Abstract nr 1282. doi:10.1158/1538-7445.AM2014-1282

Hepatoid adenocarcinoma of the colon in a patient with inflammatory bowel disease

A case is presented of a 36-year-old male with primary sclerosing cholangitis-associated inflammatory bowel disease (PSC-IBD) and two synchronous stage 1 adenocarcinomata of the colon, who was initially treated with a subtotal colectomy with ileostomy. One year later, the patient presented with extensive intra-abdominal lymphadenopathy and peritoneal carcinomatosis, as well as a markedly elevated serum level of alpha-fetoprotein (AFP). Fine needle aspiration biopsy of a porta hepatis lymph node revealed a metastatic hepatoid adenocarcinoma. Subsequent review of the previous colectomy specimen showed that one of the previously identified adenocarcinomata had features suggestive of a hepatoid colonic adenocarcinoma. The patient was subsequently treated with a cytotoxic regimen of FOLFOX (oxaliplatin, leucovorin, 5-fluorouracil) and bevacizumab, with stable results being achieved after six months. This case presents the first known report of PSC-IBD associated with synchronous typical and hepatoid adenocarcinomata of the colon and highlights the importance of considering hepatoid adenocarcinoma as a differential diagnosis in patients with an increasing serum AFP level.

Distinctive histopathologic phenotype in resection specimens from patients with Crohn's disease receiving anti-TNF-α therapy

Anti-tumor necrosis factor α (anti-TNF-α) therapy can result in endoscopic healing, reduction of symptoms, and reduced need for surgery and hospitalization in many patients with Crohn's disease (CD). Earlier data suggested that anti-TNF-α therapy may be associated with fibrosis and stricturing. We sought to determine whether anti-TNF-α therapy affects histologic inflammation, fibrosis, and granuloma formation. Hematoxylin and eosin sections from 62 patients with CD treated with either infliximab or adalimumab and 80 controls undergoing the same surgery but without prior exposure to anti-TNF-α therapy were compared. All patients with CD had undergone surgery within 6 months of therapy; CD controls were matched for steroid exposure, procedure, and indication for surgery and were subcategorized and case matched. Blinded histologic assessment of all slides was performed using a semiquantitative scoring system to assess inflammatory changes and fibrosis in all bowel layers. Compared with controls, the group treated with anti-TNF-α showed a reduction in mucosal and submucosal inflammation (P < .05), a decrease in granuloma formation (P < .05), and an increase in duplication of the muscularis mucosae (P < .05). A notable feature was a distinct pattern of hyalinizing submucosal fibrosis that was often devoid of inflammatory cells and that started directly below the muscularis mucosae; this pattern was not observed in the control group (P < .05). Resection specimens from patients with CD treated with anti-TNF-α therapy showed (a) reduced mucosal and submucosal inflammation; (b) a decrease in granuloma formation; and (c) a distinct pattern of submucosal hyaline fibrosis, with increased fibrosis in the muscularis mucosae and muscularis propria.

ARID1A/BAF250a as a prognostic marker for gastric carcinoma: a study of 2 cohorts

ARID1A/BAF250a has been recently implicated as a tumor suppressor in gastric cancer. We sought to clarify the clinical significance of BAF250a/ARID1A in relation to other clinical parameters and relevant biomarkers in gastric carcinoma. Cases from 2 separate cohorts of patients with gastric carcinoma from Vancouver (n = 173) and Toronto (n = 80) were selected for the construction of tissue microarrays, which were used to assess the immunohistochemical status of BAF250a (anti-ARID1A), mismatch repair proteins and p53, as well as in situ hybridization for HER2 amplification and Epstein-Barr virus infection. The Toronto cohort contained a higher proportion of early stage cases (P = .019) and a smaller proportion of cases from the proximal stomach (P < .001). Overall, immunohistochemical loss of BAF250a was observed in 22.5% of gastric adenocarcinomas from the Vancouver group and 20% from Toronto. In both cohorts, loss of BAF250a was positively associated with loss of mismatch repair protein expression (P < .0001 and P = .035, respectively). Loss of BAF250a expression was independently associated with poor overall survival in the Toronto cohort (P = .0015), whereas no significant association with survival was observed in the Vancouver cohort. BAF250a loss was not significantly associated with any additional clinical parameters in either cohort. HER2 amplification was confirmed as a negative prognostic factor in both cohorts. These findings suggest that ARID1A/BAF250a may be of prognostic significance in a subset of patients with early stage gastric cancer and that pathological assessment should increasingly use a multimarker approach.

Collective migration of cancer-associated fibroblasts is enhanced by overexpression of tight junction-associated proteins claudin-11 and occludin

It has been suggested that cancer-associated fibroblasts (CAFs) positioned at the desmoplastic areas of various types of cancer are capable of executing a migratory program, characterized by accelerated motility and collective configuration. Since CAFs are reprogrammed derivatives of normal progenitors, including quiescent fibroblasts, we hypothesized that such migratory program could be context-dependent, thus being regulated by specific paracrine signals from the adjacent cancer population. Using the traditional scratch assay setup, we showed that only specific colon cancer cell lines (i.e. HT29) were able to induce collective CAF migration. By performing quantitative proteomics (SILAC), we identified a 2.7-fold increase of claudin-11, a member of the tight junction apparatus, in CAFs that exerted such collectivity in their migratory pattern. Further proteomic investigations of cancer cell line secretomes revealed a specific signature, involving TGF-β, as potential mediator of this effect. Normal colonic fibroblasts stimulated with TGF-β exerted myofibroblastic differentiation, occludin (OCLN) and claudin-11 (CLDN11) overexpression and cohort formation. Subsequently, inhibition of TGF-β attenuated all the previous effects. Immunohistochemistry of the universal tight junction marker occludin in a cohort of 30 colorectal adenocarcinoma patients defined a CAF subpopulation expressing tight junctions. Overall, these data suggest that cancer cells may induce CLDN11 overexpression and subsequent collective migration of peritumoral CAFs via TGF-β secretion.

Severe cholestasis due to adalimumab in a Crohn’s disease patient

Elevation of liver biochemistry has been reported with anti-tumor necrosis factor agents, but overt liver failure rarely reported. Autoimmune hepatitis has been more commonly reported with infliximab than adalimumab (ADA). Our case, however, describes the first reported case of ADA-associated severe cholestatic injury. A 39-year-old female with Crohn’s disease developed severe jaundice after initiation of ADA. All serologic tests and imaging studies were normal. Liver biopsy showed prominent pericentral canalicular cholestasis, without features of steatosis or sclerosing cholangitis, consistent with drug-induced cholestasis. The serum total bilirubin peaked at 280 μmol/L, and improvement was seen after 5 wk with eventual normalization of liver enzymes at 10 wk. Our case describes the first reported case of ADA-associated severe cholestatic liver disease and the first histopathologic examination of this adverse drug effect. Clinicians need to be aware of this potential drug-induced liver injury when prescribing this commonly used biologic medication.

The phenotypic expression of inflammatory bowel disease in patients with primary sclerosing cholangitis differs in the distribution of colitis

BACKGROUND

Inflammatory bowel disease (IBD) associated with primary sclerosing cholangitis (PSC) is reported to be mild and prone to right-side predominance with rectal sparing. However, no dedicated studies evaluating patterns of presentation of liver disease with respect to IBD are available.

METHODS

We performed a detailed histological examination of the colonic biopsies in the context of PSC, identifying 97 patients [89 with ulcerative colitis and ten with Crohn's disease (CD)] stratified into two groups, based on their initial disease presentation: hepatic/biliary (group 1-PSC-IBD; n=56) versus colonic (group 2-IBD-PSC; n=41).

RESULTS

Inflammatory bowel disease that preceded PSC had a tendency to have a "pan-colitis" distribution; this group included all patients with CD. Inflammatory bowel disease diagnosis that followed PSC presentation was more likely to be right-sided, sparing the descending, sigmoid and rectal regions (p=0.002). In both groups, colitis was mild with focal deep plasmacytosis and occasional mild cryptitis. Active cryptitis with crypt abscesses, surface erosion and ulceration were not identified in any of the patients.

CONCLUSION

Colitis associated with PSC shows mild disease activity and the colitis pattern is associated with disease presentation, i.e. colitis preceding PSC (IBD-PSC cohort) typically have a pancolitic distribution, while colitis following PSC (PSC-IBD cohort) demonstrates right-sided predominance. Awareness by pathologists and clinicians of these patterns of inflammatory bowel disease is important and of use in directing appropriate investigations for patients.

Nucleophosmin 1, upregulated in adenomas and cancers of the colon, inhibits p53-mediated cellular senescence

Dysregulation of nucleophosmin 1 (NPM1) has been found in numerous solid and hematological malignancies. Our previous meta-analysis of colorectal cancer (CRC) high throughput gene expression profiling studies identified it as a consistently reported up-regulated gene in the malignant state. Our aims were to compare NPM1 expression in normal colon, adenoma and CRC, to correlate their expressions with clinico-pathological parameters, and to assess the biological role of aberrant NPM1 expression in CRC cells. NPM1 transcript levels were studied in human CRC cell lines, whereas a tissue microarray of 57 normal human colon, 40 adenoma and 185 CRC samples were used to analyze NPM1 protein expression by immunohistochemistry. CRC cell lines were subjected to transient siRNA-mediated knockdown to study NPM1's roles on cell viability and senescence. NPM1 transcript levels were 7-11-folds higher in three different human CRC cell lines compared to normal colon cells. NPM1 protein expression was found to be progressively and significantly upregulated in CRC compared to adenomas and in adenomas compared to normal mucosa. Reducing NPM1 expression by siRNA had caused a significant decrease in cell viability, a concomitant increase in cellular senescence and cell cycle arrest. Cellular senescence induced under conditions of forced NPM1 suppression could be prevented by knocking down p53. The differential expression of NPM1 along the normal colon-adenoma-carcinoma progression and its involvement in resisting p53 related senescent growth arrest in CRC cell lines implicate its role in supporting CRC tumorigenesis.

Analysis of microsatellite instability in gastric mucosa-associated lymphoid tissue lymphoma

In Helicobacter pylori gastritis, constant antigenic stimulation triggers a sustained B-cell proliferation. Errors made during this continuous DNA replication are supposed to be corrected by the DNA mismatch repair mechanism. Failure of this mismatch repair mechanism has been described in hereditary non-polyposis colorectal cancer (HNPCC) and results in a replication error phenotype. Inherent to their instability during replication, microsatellites are the best markers of this replication error phenotype. We aimed to evaluate the role of defects in the DNA mismatch repair (MMR) mechanism and microsatellite instability (MSI) in relation to the most frequent genetic anomaly, translocation t(11;18)(q21;q21), in gastric mucosa-associated lymphoid tissue (MALT) lymphoma. Therefore, we examined 10 microsatellite loci (BAT25, BAT26, D5S346, D17S250, D2S123, TGFB, BAT40, D18S58, D17S787 and D18S69) for instability in 28 patients with MALT lymphomas. In addition, these tumors were also immunostained for MLH1, MSH2, MSH6 and PMS2, as well as screened for the presence of t(11;18)(q21;q21) by real-time polymerase chain reaction (RT-PCR). We found MSI in 5/28 (18%) lymphomas, with MSI occurring in both t(11;18)(q21;q21)-positive and -negative tumors. One tumor displayed high levels of instability, and, remarkably, this was the only case displaying features of a diffuse large B-cell lymphoma. All microsatellite unstable lymphomas showed a loss of MSH6 expression. In conclusion, our data suggest that a MMR-defect may be involved in the development of gastric MALT lymphomas, and that a defect of MSH6 might be associated with those MSI-driven gastric lymphomas.

Absence of MMP2 expression correlates with poor clinical outcomes in rectal cancer, and is distinct from MMP1-related outcomes in colon cancer

PURPOSE

Treatments for colorectal cancer (CRC) are primarily disease stage based. However, heterogeneity in outcome within even a single stage highlights its limitations in predicting disease behavior. Recently, the role of gene expression as predictive and prognostic markers has been explored. Our objectives were to identify consistently differentially expressed genes through meta-analysis of high-throughput gene-expression studies, and evaluate their predictive and prognostic significance in colon (CC) and rectal (RC) cancers.

EXPERIMENTAL DESIGN

Publications applying high-throughput gene- expression technologies to specific CRC stages were identified. A vote counting strategy was used to identify the most significant differentially expressed genes. Their predictive and prognostic values were independently assessed in a tissue microarray of 191 cases of stage II-IV CC/RC from two tertiary care centers. Their biological effects were also examined in vitro.

RESULTS

MMP1 and MMP2 were identified as consistently underexpressed in liver metastasis compared with primary CRC. Shorter time to distant metastasis and overall survival occurred in stage III CC lacking MMP1 expression, and in stage III RC lacking MMP2. MMP1 levels in stage II and III CC were associated with increased likelihood of distant metastasis, whereas the risk of local recurrence in stage III RC could be stratified by MMP2. Promotion of cell invasion of CRC cell lines exposed to MMP1/2 inhibitors were confirmed in vitro.

CONCLUSIONS

MMP1 and MMP2 may be useful biomarkers that can help stratify patients at higher risk of developing recurrence in colorectal cancer, and guide individualized treatment decisions to achieve better outcomes.

A five year Canadian laparoscopic adjustable gastric band experience

BACKGROUND

The aim of this study was to review 5 years of laparoscopic adjustable gastric band (LAGB) procedures in which low-pressure bands were used.

METHODS

All LAGB cases at the authors' center were retrospectively analyzed. A survey of these patients was conducted in 2008 and 2009.

RESULTS

Of 90 LAGB patients, 86 were surveyed. Follow-up averaged 17.5 months. Weight loss averaged 24.8 +/- 19.4 kg. Weight loss averaged 2.7 kg/mo and did not significantly drop over the last 10.7 months (2.7 vs 1.5 kg/mo, P = .16). Excess body weight loss was 27.5%, 39.1%, and 67.2% in the first, second, and following years, respectively. Patients averaged 4.14 adjustments of their bands and vomited 2.13 times per week. The mortality rate was 0%. No band slippages or band erosion occurred. Resolution or improvement occurred in most obesity-related illness. Gastroesophageal reflux disease symptoms worsened in 25% of patients.

CONCLUSIONS

These results replicate world LAGB literature. Low complication rates result either from the authors' band or their techniques.

Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3) overexpression in pancreatic ductal adenocarcinoma correlates with poor survival

Background

Pancreatic ductal adenocarcinoma is a lethal disease with a 5-year survival rate of 4% and typically presents in an advanced stage. In this setting, prognostic markers identifying the more agrressive tumors could aid in managment decisions. Insulin-like growth factor 2 mRNA binding protein 3 (IGF2BP3, also known as IMP3 or KOC) is an oncofetal RNA-binding protein that regulates targets such as insulin-like growth factor-2 (IGF-2) and ACTB (beta-actin).

Methods

We evaluated the expression of IGF2BP3 by immunohistochemistry using a tissue microarray of 127 pancreatic ductal adenocarcinomas with tumor grade 1, 2 and 3 according to WHO criteria, and the prognostic value of IGF2BP3 expression.

Results

IGF2BP3 was found to be selectively overexpressed in pancreatic ductal adenocarcinoma tissues but not in benign pancreatic tissues. Nine (38%) patient samples of tumor grade 1 (n = 24) and 27 (44%) of tumor grade 2 (n = 61) showed expression of IGF2BP3. The highest rate of expression was seen in poorly differentiated specimen (grade 3, n = 42) with 26 (62%) positive samples. Overall survival was found to be significantly shorter in patients with IGF2BP3 expressing tumors (P = 0.024; RR 2.3, 95% CI 1.2-4.8).

Conclusions

Our data suggest that IGF2BP3 overexpression identifies a subset of pancreatic ductal adenocarcinomas with an extremely poor outcome and supports the rationale for developing therapies to target the IGF pathway in this cancer.

Tumor expression of integrin-linked kinase (ILK) correlates with the expression of the E-cadherin repressor snail: an immunohistochemical study in ductal pancreatic adenocarcinoma

Integrin-linked kinase (ILK) is a key molecule involved in mediating several biological functions including cell-matrix interactions, angiogenesis, and invasion, as well as playing a role in epithelial to mesenchymal transition (EMT) in cancer cells. In ductal pancreatic adenocarcinoma, increased expression of ILK has been linked to tumor prognosis and correlated with increased chemoresistance to drugs, such as gemcitabine. However, the precise relationship between ILK, Snail, E-cadherin, and N-cadherin expression on the stepwise development of pancreatic cancer is unknown. Hence, the purpose of this work was to investigate levels of expression of ILK, Snail, and the cadherins in pancreatic intraepithelial neoplasia (PanIN), and cancer. Resection specimens of 25 randomly selected patients, who underwent a pyloric preserving pancreatoduodenectomy for ductal pancreatic adenocarcinoma, were utilized for this study. Formalin-fixed paraffin embedded pancreatic tissue was immunostained for ILK, E-cadherin, N-cadherin, and Snail by standard techniques. The extent of staining positivity was scored and the results correlated with clinicopathological parameters. In 23 of 25 cases, ILK expression showed extensive positivity (>50%), while two cases did not demonstrate any ILK staining. PanIN grades 1 (n = 16), 2 (n = 11), and 3 (n = 19) lesions demonstrated only focal positivity (<10%) for ILK. E-cadherin showed a reciprocal staining pattern to ILK in 21 of 25 cases, with only focal expression of the marker in pancreatic adenocarcinoma. Interestingly, 15 of 19 PanIN-3 lesions expressed extensive E-cadherin staining. N-cadherin, however, was moderately expressed in the majority of cases (n = 18). Snail expression (n = 22) correlated with ILK expression in ductal pancreatic adenocarcinoma (rho = 0.8168, p = 0.02), but only minimal Snail staining activity was detected in PanIN lesions. The increase in expression of the E-cadherin repressor Snail, as well as the related increase in the ILK expression, may point towards an ILK-mediated induction, opening possible avenues for targeted drug therapy.