Successful immune checkpoint blockade in a patient with advanced stage microsatellite-unstable biliary tract cancer

The role of germline BRCA1 & BRCA2 mutations in familial pancreatic cancer: A systematic review and meta-analysis

BACKGROUND

Familial Pancreatic Cancer (FPC) presents a notable risk, with 3-10% of pancreatic adenocarcinoma cases having a family history. Studies link FPC to syndromes like HBOC, suggesting BRCA1/BRCA2 mutations play a role. BRCA gene functions in DNA repair impact FPC management, influencing sensitivity to therapies like PARP inhibitors. Identifying mutations not only aids FPC treatment but also reveals broader cancer risks. However, challenges persist in selectively applying genetic testing due to cost constraints. This Systematic Review focuses on BRCA1/BRCA2 significance in FPC, diagnostic criteria, prognostic value, and limitations.

METHOD

Original articles published from 2013 to January 2023 were sourced from databases such as Scopus, PubMed, ProQuest, and ScienceDirect. Inclusion criteria comprised observational cohort or diagnostic studies related to the role of BRCA1/2 mutation in correlation to familial pancreatic cancer (FPC), while article reviews, narrative reviews, and non-relevant content were excluded. The assessment of bias used ROBINS-I, and the results were organized using PICOS criteria in a Google spreadsheet table. The systematic review adhered to the PRISMA 2020 checklist.

RESULT

We analyzed 9 diagnostic studies encompassing 1325 families and 4267 patients from Italy, USA, and Poland. Despite the limitation of limited homogenous PICO studies, our findings effectively present evidence. BRCA1/2 demonstrates benefits in detecting first-degree relatives FPC involvement with 2.26-10 times higher risk. These mutation findings also play an important role since with the BRCA1/2 targeted therapy, Poly-ADP Ribose Polymerase inhibitors (PARP) may give better outcomes of FPC treatment. Analysis of BRCA1 and BRCA2 administration's impact on odds ratio (OR) based on six and five studies respectively. BRCA1 exhibited non-significant effects (OR = 1.26, P = 0.51), while BRCA2 showed significance (OR = 1.68, P = 0.04). No heterogeneity observed, indicating consistent results. Further research on BRCA1 is warranted.

CONCLUSION

Detecting the BRCA1/2 mutation gene offers numerous advantages, particularly in its correlation with FPC. For diagnostic and prognostic purposes, testing is strongly recommended for first-degree relatives, who face a significantly higher risk (2.26-10 times) of being affected. Additionally, FPC patients with identified BRCA1/2 mutations exhibit a more favorable prognosis compared to the non-mutated population. This is attributed to the availability of targeted BRCA1/2 therapy, which maximizes treatment outcomes.

Molecular diagnostics of hepatobiliary and pancreatic neoplasias

Neoplasias of the hepatopancreatobiliary tract are growing in numbers, have the poorest prognosis of all major cancer entities, and thus represent a rising clinical problem. Their molecular diagnostic has dramatically improved, contributing to tumor subtyping, definition of malignancy, and uncovering cases with hereditary predisposition. Most of all, predictive molecular testing allows to identify cases amenable to treatment with the rising number of approved targeted drugs, immune-oncological treatment, and clinical trials. In this review, the current state of molecular testing and its contribution to clinical decision-making are outlined.

Immunogenomics of cholangiocarcinoma

The development of cholangiocarcinoma spans years, if not decades, during which the immune system becomes corrupted and permissive to primary tumor development and metastasis. This involves subversion of local immunity at tumor sites, as well as systemic immunity and the wider host response. While immune dysfunction is a hallmark of all cholangiocarcinoma, the specific steps of the cancer-immunity cycle that are perturbed differ between patients. Heterogeneous immune functionality impacts the evolutionary development, pathobiological behavior, and therapeutic response of these tumors. Integrative genomic analyses of thousands of primary tumors have supported a biological rationale for immune-based stratification of patients, encompassing immune cell composition and functionality. However, discerning immune alterations responsible for promoting tumor initiation, maintenance, and progression from those present as bystander events remains challenging. Functionally uncoupling the tumor-promoting or tumor-suppressing roles of immune profiles will be critical for identifying new immunomodulatory treatment strategies and associated biomarkers for patient stratification. This review will discuss the immunogenomics of cholangiocarcinoma, including the impact of genomic alterations on immune functionality, subversion of the cancer-immunity cycle, as well as clinical implications for existing and novel treatment strategies.

Case report: Remarkable response to sintilimab, lenvatinib, and nab-paclitaxel in postoperative metastatic chemotherapy-resistant combined hepatocellular-cholangiocarcinoma

Background: Combined hepatocellular-cholangiocarcinoma (cHCC-CCA) is a highly aggressive malignancy with a poor prognosis. However, there are no consensus treatment guidelines, and decisions are usually extrapolated from intrahepatic cholangiocarcinoma (ICC) or hepatocellular carcinoma (HCC). Given that cHCC-CCA owns the unequivocal presence of both hepatocytic and cholangiocytic differentiation, a combination regimen of anti-PD1 antibody, multikinase inhibitor, and chemotherapy targeting against both components might be an optimal choice. Case presentation: We present the case of a patient with postoperative metastatic chemotherapy-resistant cHCC-CCA who exhibited a durable response and reasonable tolerability to a combination therapy consisting of the anti-PD1 antibody sintilimab, multikinase inhibitor lenvatinib, and nab-paclitaxel, despite having a low tumor mutational burden (TMB-L), microsatellite stability (MSS), and negative programmed cell death 1 ligand 1 (PD-L1). Conclusion: The combination regimen of immune checkpoint inhibitor sintilimab, multikinase inhibitor lenvatinib, and chemotherapy with nab-paclitaxel, which targets both the HCC and ICC components, may represent a promising treatment option for patients with cHCC-CCA. Further research is warranted to validate these findings in larger patient cohorts.

A Case of Advanced Multifocal Cholangiocarcinoma With Excellent Response to Pembrolizumab

The role of immune checkpoint inhibitors (ICIs) continues to receive more attention as evidence emerges of their efficacy and improved survival in patients with advanced biliary tract malignancies including cholangiocarcinoma (CCA). In line with this evidence, we describe the case of a 52-year-old male patient who presented initially in October 2019 with abdominal pain. Investigations revealed multifocal hepatic masses that proved to be CCA that was considered unresectable. Chemotherapy with cisplatin (C) and gemcitabine (G) was initiated. In January 2020, progressive disease was noted, prompting the initiation of 5-fluorouracil (5-FU) and oxaliplatin along with pembrolizumab. Since March 2020, pembrolizumab monotherapy was pursued with radiological evidence of excellent response. Pembrolizumab monotherapy was continued through August 2022, where positron emission tomography (PET)/CT scan showed no evidence of active disease. This case serves to supplement the ongoing evidence of ICI efficacy especially as a durable, sustained radiological response was evident for more than three years from the time of diagnosis.

Response to Immune Checkpoint Inhibitors Is Affected by Deregulations in the Antigen Presentation Machinery: A Systematic Review and Meta-Analysis

Immune checkpoint inhibitors (ICI) targeting programmed death 1 (PD-1), its ligand (PD-L1), or cytotoxic T-lymphocyte antigen 4 (CTLA-4) have shown promising results against multiple cancers, where they reactivate exhausted T cells primed to eliminate tumor cells. ICI therapies have been particularly successful in hypermutated cancers infiltrated with lymphocytes. However, resistance may appear in tumors evading the immune system through alternative mechanisms than the PD-1/PD-L1 or CTLA-4 pathways. A systematic pan-cancer literature search was conducted to examine the association between alternative immune evasion mechanisms via the antigen presentation machinery (APM) and resistance towards ICI treatments targeting PD-1 (pembrolizumab and nivolumab), PD-L1 (durvalumab, avelumab, and atezolizumab), and CTLA-4 (ipilimumab). The APM proteins included the human leucocyte antigen (HLA) class I, its subunit beta-2 microglobulin (B2M), the transporter associated with antigen processing (TAP) 1, TAP2, and the NOD-like receptor family CARD domain containing 5 (NLRC5). In total, 18 cohort studies (including 21 original study cohorts) containing 966 eligible patients and 9 case studies including 12 patients were reviewed. Defects in the APM significantly predicted poor clinical benefit with an odds ratio (OR) of 0.39 (95% CI 0.24−0.63, p < 0.001). The effect was non-significant, when considering complete and partial responses only (OR = 0.52, 95% CI 0.18−1.47, p = 0.216). In summary, the APM contains important targets for tumorigenic alterations which may explain insensitivity towards ICI therapy.

Clinical treatment of cholangiocarcinoma: an updated comprehensive review

Cholangiocarcinoma (CCA) is a heterogeneous group of neoplasms of the bile ducts and represents the second most common hepatic cancer after hepatocellular carcinoma; it is sub-classified as intrahepatic cholangiocarcinoma (iCCA) and extrahepatic cholangiocarcinoma (eCCA), the latter comprising both perihilar cholangiocarcinoma (pCCA or Klatskin tumor), and distal cholangiocarcinoma (dCCA). The global incidence of CCA has increased worldwide in recent decades. Chronic inflammation of biliary epithelium and bile stasis represent the main risk factors shared by all CCA sub-types. When feasible, liver resection is the treatment of choice for CCA, followed by systemic chemotherapy with capecitabine. Liver transplants represent a treatment option in patients with very early iCCA, in referral centers only. CCA diagnosis is often performed at an advanced stage when CCA is unresectable. In this setting, systemic chemotherapy with gemcitabine and cisplatin represents the first treatment option, but the prognosis remains poor. In order to ameliorate patients' survival, new drugs have been studied in the last few years. Target therapies are directed against different molecules, which are altered in CCA cells. These therapies have been studied as second-line therapy, alone or in combination with chemotherapy. In the same setting, the immune checkpoints inhibitors targeting programmed death 1 (PD-1), programmed death-ligand 1 (PD-L1), cytotoxic T-lymphocyte antigen-4 (CTLA-4), have been proposed, as well as cancer vaccines and adoptive cell therapy (ACT). These experimental treatments showed promising results and have been proposed as second- or third-line treatment, alone or in combination with chemotherapy or target therapies.

OncoPan®: An NGS-Based Screening Methodology to Identify Molecular Markers for Therapy and Risk Assessment in Pancreatic Ductal Adenocarcinoma

Pancreatic cancer has a high morbidity and mortality with the majority being PC ductal adenocarcinomas (PDAC). Whole genome sequencing provides a wide description of genomic events involved in pancreatic carcinogenesis and identifies putative biomarkers for new therapeutic approaches. However, currently, there are no approved treatments targeting driver mutations in PDAC that could produce clinical benefit for PDAC patients. A proportion of 5–10% of PDAC have a hereditary origin involving germline variants of homologous recombination genes, such as Mismatch Repair (MMR), STK11 and CDKN2A genes. Very recently, BRCA genes have been demonstrated as a useful biomarker for PARP-inhibitor (PARPi) treatments. In this study, a series of 21 FFPE PDACs were analyzed using OncoPan®, a strategic next-generation sequencing (NGS) panel of 37 genes, useful for identification of therapeutic targets and inherited cancer syndromes. Interestingly, this approach, successful also on minute pancreatic specimens, identified biomarkers for personalized therapy in five PDAC patients, including two cases with HER2 amplification and three cases with mutations in HR genes (BRCA1, BRCA2 and FANCM) and potentially eligible to PARPi therapy. Molecular analysis on normal tissue identified one PDAC patient as a carrier of a germline BRCA1 pathogenetic variant and, noteworthy, this patient was a member of a family affected by inherited breast and ovarian cancer conditions. This study demonstrates that the OncoPan® NGS-based panel constitutes an efficient methodology for the molecular profiling of PDAC, suitable for identifying molecular markers both for therapy and risk assessment. Our data demonstrate the feasibility and utility of these NGS analysis in the routine setting of PDAC molecular characterization.

Dissecting Intra-Tumoral Changes Following Immune Checkpoint Blockades in Intrahepatic Cholangiocarcinoma via Single-Cell Analysis

Purpose

To dissect the tumor ecosystem following immune checkpoint blockades (ICBs) in intrahepatic cholangiocarcinoma (ICC) at a single-cell level.

Methods

Single-cell RNA sequencing (scRNA-seq) data of 10 ICC patients for the ICB clinical trial were extracted from GSE125449 and systematically reanalyzed. Bulk RNA-seq data of 255 ICC patients were analyzed. Infiltration levels of SPP1⁺CD68⁺ tumor-associated macrophages (TAMs) were examined by dual immunofluorescence (IF) staining in 264 resected ICC samples. The correlation between SPP1⁺ TAMs and clinicopathological features as well as their prognostic significance was evaluated.

Results

Among the 10 patients, five received biopsy at baseline, and others were biopsied at different timings following ICBs. Single-cell transcriptomes for 5,931 cells were obtained. A tighter cellular communication network was observed in ICB-treated ICC. We found a newly emerging VEGF signaling mediated by PGF-VEGFR1 between cancer-associated fibroblasts (CAFs) and endothelial cells in ICC following ICBs. SPP1 expression was dramatically upregulated, and SPP1⁺ TAM gene signatures were enriched in TAMs receiving ICB therapy. We also identified SPP1⁺ TAMs as an independent adverse prognostic indicator for survival in ICC.

Conclusion

Our analyses provide an overview of the altered tumor ecosystem in ICC treated with ICBs and highlight the potential role of targeting CAFs and SPP1⁺TAMs in developing a more rational checkpoint blockade-based therapy for ICC.

Targeted Therapies for Perihilar Cholangiocarcinoma

Perihilar cholangiocarcinoma (pCCA) is the anatomical sub-group of biliary tract cancer (BTC) arising between the second-order intrahepatic bile ducts and the cystic duct. Together with distal and intrahepatic cholangiocarcinoma (dCCA and iCCA; originating distal to, and proximal to this, respectively), gallbladder cancer (GBC) and ampulla of Vater carcinoma (AVC), these clinicopathologically and molecularly distinct entities comprise biliary tract cancer (BTC). Most pCCAs are unresectable at diagnosis, and for those with resectable disease, surgery is extensive, and recurrence is common. Therefore, the majority of patients with pCCA will require systemic treatment for advanced disease. The prognosis with cytotoxic chemotherapy remains poor, driving interest in therapies targeted to the molecular nature of a given patient's cancer. In recent years, the search for efficacious targeted therapies has been fuelled both by whole-genome and epigenomic studies, looking to uncover the molecular landscape of CCA, and by specifically testing for aberrations where established therapies exist in other indications. This review aims to provide a focus on the current molecular characterisation of pCCA, targeted therapies applicable to pCCA, and future directions in applying personalised medicine to this difficult-to-treat malignancy.

Pancreatic Cancer with Mutation in BRCA1/2, MLH1, and APC Genes: Phenotype Correlation and Detection of a Novel Germline BRCA2 Mutation

Pancreatic ductal adenocarcinoma (PDAC) is the seventh leading cause of cancer death worldwide; most of cases are sporadic, however about 5% to 10% report a hereditary predisposition. Several hereditary syndromes have been associated with familial pancreatic cancer (FPC) onset, including hereditary breast and ovarian cancer syndrome (HBOC), Lynch syndrome (LS), Familial atypical multiple mole melanoma (FAMMM), Familial adenomatous polyposis (FAP), Li-Fraumeni syndrome (LFS), Peutz-Jeghers syndrome (PJS), and Hereditary pancreatitis (HP).The aim of this study was to determine the mutational status of a cohort of 56 HBOC families, 7 LS families, 3 FAP and FAMMM families, and 1 LFS family with at least one case of PDAC. Mutation analysis of BRCA1/2, ATM, CHEK2, PALB2, RAD51C, RAD51D, NBN, CDH1, TP53, MLH1, MSH2, MSH6, and PMS2 genes, showedmutation in BRCA1/2, MLH1, and APC genes. We founda high mutation rate in patients belong HBOC and LS families, with a percentage of 28.6% in both syndromes and prevalence in HBOC of BRCA2 mutations with one case of double mutation in BRCA2 gene. In FAP family, we found a pathogenic mutation in APC gene in 1/3 families. We observed an early onset of PDAC and a lower survival in PDAC patients belonging to mutated families, while no evidence of possible pancreatic cancer cluster regions was found. Moreover, we identified a novel BRCA2 germline mutation, c.5511delT (p.Phe1837LeufsX3), not reported in any database, that segregated with disease in HBOC patients. Mutational analysis was extended to family membersof mutated patients, both healthy and cancer affected, which revealed 23 unaffected family members that inherited the proband's mutation. Although correlative by its nature, the presence of a BRCA mutation in PDAC patients may have benefits in terms of optimized treatment and longer outcome.

Placental growth factor promotes tumour desmoplasia and treatment resistance in intrahepatic cholangiocarcinoma

OBJECTIVE

Intrahepatic cholangiocarcinoma (ICC)-a rare liver malignancy with limited therapeutic options-is characterised by aggressive progression, desmoplasia and vascular abnormalities. The aim of this study was to determine the role of placental growth factor (PlGF) in ICC progression.

DESIGN

We evaluated the expression of PlGF in specimens from ICC patients and assessed the therapeutic effect of genetic or pharmacologic inhibition of PlGF in orthotopically grafted ICC mouse models. We evaluated the impact of PlGF stimulation or blockade in ICC cells and cancer-associated fibroblasts (CAFs) using in vitro 3-D coculture systems.

RESULTS

PlGF levels were elevated in human ICC stromal cells and circulating blood plasma and were associated with disease progression. Single-cell RNA sequencing showed that the major impact of PlGF blockade in mice was enrichment of quiescent CAFs, characterised by high gene transcription levels related to the Akt pathway, glycolysis and hypoxia signalling. PlGF blockade suppressed Akt phosphorylation and myofibroblast activation in ICC-derived CAFs. PlGF blockade also reduced desmoplasia and tissue stiffness, which resulted in reopening of collapsed tumour vessels and improved blood perfusion, while reducing ICC cell invasion. Moreover, PlGF blockade enhanced the efficacy of standard chemotherapy in mice-bearing ICC. Conclusion PlGF blockade leads to a reduction in intratumorous hypoxia and metastatic dissemination, enhanced chemotherapy sensitivity and increased survival in mice-bearing aggressive ICC.

Complete Pathological Response to Neoadjuvant Chemoimmunotherapy in a Patient With Metastatic Intrahepatic Cholangiocarcinoma With High Tumor Mutational Burden

Intrahepatic cholangiocarcinoma (ICC) is an aggressive biliary tract cancer (BTC) with distinct anatomic, molecular, and clinical characteristics. Over the last 10-20 years, ICC has become the focus of increasing concern largely due to its rising incidence and high mortality rates in various parts of the world, including the United States.

Surgery is the only potentially curative treatment option for ICC; however, recurrence rate is high, and prognosis is poor in patients with recurrent disease. The chemotherapy regimen of gemcitabine-cisplatin (GemCis) is still the standard of care for patients with unresectable metastatic ICC. There is limited data regarding pathologic ICC response to palliatively intentioned systemic treatment.

Here, we report a case of a 47-year-old Caucasian male with metastatic ICC microsatellite stable (MSS) and TMB 49 mutation per megabase who achieved complete pathological response with sequential GemCis/nab-paclitaxel and pembrolizumab. This case highlights the effect of sequential neoadjuvant chemoimmunotherapy in a patient with high tumor mutational burden (TMB-H) ICC, emphasizing the importance of molecular testing, which provides valuable information that can be used in clinical practice to better select targeted chemotherapy regimens.

Low prevalence of biliary tract cancer with defective mismatch repair genes in a Japanese hospital-based population

Recent studies have reported that immune checkpoint inhibitors are effective against various defective mismatch repair (dMMR)/microsatellite instability-high (MSI-H) cancers. A limited number of reports are available on the frequency of dMMR/MSI-H carcinoma in biliary tract cancer (BTC), describing its clinicopathological characteristics and prognosis. The latter carcinoma is also associated with Lynch syndrome (LS). The present study was performed to investigate the frequency of patients with dMMR/MSI-H in BTC and the clinical characteristics of BTC with dMMR/MSI-H in a single institution in Japan. A total of 116 patients with BTC who underwent curative surgical resection at Kagawa University Hospital between January 2008 and December 2017 were included. The protein expression levels of the mismatch repair (MMR) genes [mutL homolog 1 (MLH1), mismatch repair endonuclease PMS2 (PMS2), MutS homolog (MSH)2 and MSH6] were assessed by immunohistochemistry (IHC) using formalin-fixed paraffin-embedded tissue specimens. Subsequently, MSI testing was performed on patients who exhibited loss of MMR protein expression. Loss of expression of one or more proteins was detected in five cases (4.3%). Loss of MLH1/PMS2 expression was observed in one case of intrahepatic cholangiocarcinoma, whereas loss of PMS2 expression was noted in one case of perihilar cholangiocarcinoma. Loss of MSH2/MSH6 and MSH6 expression was noted in two cases of distal cholangiocarcinoma and loss of PMS2 expression in one case of ampullary carcinoma. Out of the five patients, two demonstrated MSI-H. Microsatellite stability was observed in two cases and for one case, no data were available. Two MSI-H cases were patients with loss of expression of MLH1/PMS2 and MSH2/MSH6. None of the five patients exhibited a past medical history or family history of suspected LS. The frequency of dMMR in BTC was ~5%, which was similar to that reported by similar studies performed in other countries. In the present study, IHC appeared to be more useful than MSI testing for detecting MMR abnormalities with regards to the detection rate. Furthermore, there may only be a limited number of patients with BTCs who are likely to benefit from the therapeutic effects of treatment with immune checkpoint inhibitors.

Immune Microenvironment in Gallbladder Adenocarcinomas

Programmed death-1 (PD1) expression has not been reported in gallbladder adenocarcinoma. In this study we examined PD1 expression in gallbladder cancer to explore the correlation between PD1 expression and the clinicopathologic parameters. We found that 98% (46/47) cases expressed programmed death-ligand 1 (PD-L1) with 85% cases being PD-L1 3+. PD1+ tumor-infiltrating lymphocytes (TILs) were present in 78.7% cases (37/47). The tumor size was significantly smaller and the stromal CD3+ TILs were significantly higher in tumors with PD1+ TILs than those with PD1- TILs. In the tumors with size of <3 cm, stromal CD3+ TILs >115/HPF or stromal CD8+ TILs >45/HPF were associated with much better survival than those with stromal CD3+ TILs ≤115/HPF or stromal CD8+ TILs ≤45/HPF. In tumors with the size of 3 cm or larger, PD1+ TILs or stromal CD8+ TILs >45/HPF carried a significantly poorer survival than PD1- tumors or stromal CD8+ TILs <=45/HPF. No correlation was identified between PD1 expression and lymphovascular invasion, distant metastasis, pathologic tumor stage or prognostic stage. Multivariate survival analysis showed that tumor TNM stage and age were independent prognostic factors in gallbladder adenocarcinomas. We conclude that gallbladder adenocarcinomas may have high PD-L1 expression and PD1+ TILs. Smaller tumor size and greater amount of stromal CD3+ T cells were found in tumors with PD1+ TILs. In small tumors (<3 cm), high stromal CD3+ TILs or high stromal CD8+ TILs were associated with better survival. However, in large tumors (≥3 cm), PD1+ TILs or high stromal CD8+ TILs carried a poorer survival. Our study implied that immune-based therapy including PD1/PD-L1 checkpoint blockade might be useful in gallbladder adenocarcinomas.

Rare DNA Mismatch Repair-Related Protein Loss in Patients with Intrahepatic Cholangiocarcinoma and Combined Hepatocellular-Cholangiocarcinoma and Their Response to Immunotherapy

Purpose

The patients with advanced mismatch repair deficiency (dMMR) cancers can benefit from programmed cell death 1 (PD-1) pathway blockade, regardless of the tumor type. Little is known about the prevalence of dMMR in intrahepatic cholangiocarcinoma (ICC) and combined hepatocellular-cholangiocarcinoma (cHCC-CC). This study aimed to assess the mismatch repair (MMR)-related protein expression in patients with ICC and cHCC-CC.

Patients and Methods

Formalin-fixed, paraffin-embedded tumor specimens were obtained from patients undergoing surgery at the West china Hospital between 2009 and 2017. The immunoreactions for MLH1, MSH2, MSH6, and PMS2 were investigated to determine the MMR status.

Results

A total of 97 patients were evaluated, including 73 ICC patients and 24 cHCC-CC patients. The prevalence of dMMR was only found in two cases of 97 patients (2.06%). Both patients are ICC. In 24 cHCC-CC patients, no dMMR was observed. They did not receive an adjuvant chemotherapy after surgery. At the end of the follow-up, one patient was in a tumor-free state, and the other patient had local recurrence and metastasis. After receiving sintilimumab (an immune checkpoint inhibitor [ICI] for PD- 1), the patient had a partial response.

Conclusion

DMMR was detected in few patients with ICC and cHCC-CC. Thus, it is not recommended to routinely evaluate the MMR status of patients with ICC or cHCC-CC after surgery, but that of patients with advanced ICC or cHCC-CC should be assessed.

Successful pembrolizumab treatment of microsatellite instability-high intrahepatic cholangiocarcinoma: A case report

The tumor reduction effect of pembrolizumab is extremely high compared to standard chemotherapy and might show prolonged survival. Therefore, the MSI status should be examined in patients with cholangiocarcinoma.

Current Progress and Future Perspectives of Immune Checkpoint Inhibitors in Biliary Tract Cancer

Biliary tract cancer (BTC) is an uncommon and aggressive neoplasm, with most patients presenting in an advanced stage. Systemic chemotherapy is the limited treatment available but is unsatisfactory, while targeted therapy is still awaiting validation from clinical trials. Given the potential effect of immune checkpoint inhibitors (ICIs) in the treatment of BTC, this review aims to summarize the evidence-based benefits and predictive biomarkers for using inhibitors of cytotoxic T-lymphocyte-associated protein-4 (CTLA-4) ligand, or programmed cell death protein-1 and its ligand (PD-1 and PD-L1) as monotherapy or combined with other anti-tumor therapies, while also pointing out certain pitfalls with the use of ICIs which need to be addressed.

Pathogenesis of Cholangiocarcinoma

Cholangiocarcinoma (CCA) encompasses a group of malignancies that can arise at any point in the biliary tree. Although considered a rare cancer, the incidence of CCA is increasing globally. The silent and asymptomatic nature of these tumors, particularly in their early stages, in combination with their high aggressiveness, intra- and intertumor heterogeneity, and chemoresistance, significantly compromises the efficacy of current therapeutic options, contributing to a dismal prognosis. During the last few years, increasing efforts have been made to unveil the etiologies and pathogenesis of these tumors and to develop more effective therapies. In this review, we summarize current findings in the field of CCA, mainly focusing on the mechanisms of pathogenesis, cells of origin, genomic and epigenetic abnormalities, molecular alterations, chemoresistance, and therapies.

Microsatellite Instability-high Intrahepatic Cholangiocarcinoma with Portal Vein Tumor Thrombosis Successfully Treated with Pembrolizumab

A 60-year-old man presented with postoperative recurrence of intrahepatic cholangiocarcinoma with right portal vein tumor thrombosis (PVTT). After failure of standard chemotherapy, a liver biopsy showed that his microsatellite instability (MSI) status was high. Treatment with the immune checkpoint inhibitor (ICI) pembrolizumab was commenced, which resulted in a partial response and resolution of the PVTT. There were no significant immune-related adverse events. According to recently published reports, the frequency of MSI-high biliary tract cancer (BTC) is about 0-2.1%, which is extremely rare. However, ICIs may be effective in patients with MSI-high BTC, such as the present patient.

Undifferentiated carcinoma of the transverse colon with rhabdoid features that developed during treatment of non-small cell lung carcinoma with pembrolizumab: a case report

BACKGROUND

Undifferentiated carcinoma of the colon is rare, and its prognosis is very poor. We report a case of undifferentiated carcinoma of the colon with rhabdoid features developed during treatment of non-small lung carcinoma (NSCLC) with pembrolizumab.

CASE PRESENTATION

A 58-year-old man was diagnosed with transverse colon cancer during chemotherapy with pembrolizumab for NSCLC. Laparoscopic right hemicolectomy was performed. The histopathological diagnosis was undifferentiated carcinoma with rhabdoid features and lymph node metastasis. Immunohistochemically, programmed death ligand 1 (PD-L1) showed positivity. The microsatellite instability (MSI) status was low. He continued to receive pembrolizumab for NSCLC, and there have been no signs of colon cancer recurrence and progression of NSCLC for 15 months.

CONCLUSION

We present the case of an undifferentiated carcinoma of the transverse colon with rhabdoid features. The development of the tumor with the expression of PD-L1 during pembrolizumab might have been associated with the low MSI.

The Current Landscape of Immune Checkpoint Inhibition for Solid Malignancies

Immunotherapy has led to unprecedented improvement in the treatment and prognosis of high-risk resectable and metastatic disease across cancer types. Nowhere is this better highlighted than in the management of advanced and metastatic melanoma with the introduction of molecularly targeted therapies and immune checkpoint inhibitors. Following their success in melanoma, immunotherapies have also been evaluated and their use approved in the management across a variety of other solid malignancies in the neoadjuvant, adjuvant, and advanced/metastatic setting. This review provides an overview of the current landscape of immune checkpoint inhibition for solid malignancies.

Mismatch Repair Protein Deficiency/Microsatellite Instability Is Rare in Cholangiocarcinomas and Associated With Distinctive Morphologies

OBJECTIVES

Although germline mutations of mismatch repair (MMR) genes (Lynch syndrome) are not typically associated with cholangiocarcinomas, the US Food and Drug Administration recently approved the use of pembrolizumab in patients with advanced solid tumors at all sites that show MMR deficiency or associated high microsatellite instability.

METHODS

We analyzed 96 cases of intra- and extrahepatic cholangiocarcinomas for morphology using H&E and for MMR status using immunohistochemical staining. We submitted any results with MMR loss for microsatellite instability testing.

RESULTS

We found that 6% of samples showed MMR deficiency. The best predictive factor was a nontypical infiltrating pattern of invasion (P < .0001). No patients with MMR deficiency had a history of a cancer typically associated with Lynch syndrome.

CONCLUSIONS

Solid, mucinous, or signet-ring appearance of a cholangiocarcinoma should prompt MMR testing for immunotherapy options but should not necessarily raise concern about Lynch syndrome.

Systemic therapies for intrahepatic cholangiocarcinoma

Intrahepatic cholangiocarcinoma (iCCA) is a highly lethal hepatobiliary neoplasm whose incidence is increasing. Largely neglected for decades as a rare malignancy and frequently misdiagnosed as carcinoma of unknown primary, considerable clinical and investigative attention has recently been focused on iCCA worldwide. The established standard of care includes first-line (gemcitabine and cisplatin), second-line (FOLFOX) and adjuvant (capecitabine) systemic chemotherapy. Compared to hepatocellular carcinoma, iCCA is genetically distinct with several targetable genetic aberrations identified to date. Indeed, FGFR2 and NTRK fusions, and IDH1 and BRAF targetable mutations have been comprehensively characterised and clinical data is emerging on targeting these oncogenic drivers pharmacologically. Also, the role of immunotherapy has been examined and is an area of intense investigation. Herein, in a timely and topical manner, we will review these advances and highlight future directions of research.

Immunohistochemical mismatch repair proteins expression as a tool to predict the melanoma immunotherapy response

In difference to other solid malignancies, the identification of biomarkers for the prediction of malignant melanoma (MM) response to immunotherapy is limited. The aim of the current study was to evaluate the immunohistochemical (IHC) expression of MMR proteins in a cohort of MM metastatic patients receiving anti PD-1 treatments. The therapeutic response of patients was also retrospectively assessed. The cohort of the current study included 14 patients with advanced MM that had received anti PD-1 from January 2014 to December 2016 (12 males, 2 females; average age, 71 years; age range, 47–88 years). IHC analysis of MLH1, PMS2, MSH2 and MSH6 proteins was performed on paraffin-embedded primary tumor samples from each patient and on the 23 available metastasis specimens obtained from the Division of Pathology (University of Modena and Reggio Emilia). The results revealed that 7% of the primary melanoma tissue obtained from the patient cohort exhibited the loss of expression of at least one MMR protein. Three samples from one patient, including one primary melanoma and two metastases, exhibited no MSH6 expression and had the most successful response to anti PD-1 treatment, with a progression-free survival and overall survival of 956 and 2,546 days, respectively. In conclusion, the assessment of MMR protein expression represents a potential predictive marker that may have critical importance for patients with primary and metastatic MM, primarily as criterion for the adoption of immunotherapy treatments.

The Clinicopathological and Prognostic Value of PD-L1 Expression in Cholangiocarcinoma: A Meta-Analysis

Background: Recently, blockade of immune checkpoint has emerged as one of the most potential treatments for solid tumors. Programmed cell death ligand 1(PD-L1), a member of the B7 family of molecules, plays a crucial role in tumor immunobiology. However, the prognostic significance of PD-L1 in cholangiocarcinoma (CCA) patients remains controversial. This study aimed to inquire into the prognostic and clinicopathological significance of PD-L1 in CCA via a meta-analysis.

Methods: We searched PubMed, the Cochrane Library, Embase, Web of Science and Google Scholar up to April 2019, regardless of the region or language, for studies on the correlation between clinicopathology/prognosis and PD-L1 in patients with CCA. The pooled hazard ratios (HRs) and 95% confidence intervals (CIs) were calculated to investigate the prognostic significance of PD-L1 expression in cholangiocarcinoma. The odds ratios (ORs) were also determined to explore the association between PD-L1 expression and clinicopathological features.

Results: Our meta-analysis included 11 studies with 1,066 patients. The meta-analysis of these studies indicated a trend that high PD-L1 expression indicated a poor OS, but the result was not statistically significant (HR = 1.62, 95% CI [0.98–2.68], p = 0.063). For DFS, although the pooled result is not statistically significant, it trends toward being significant that high PD-L1 expression indicated improved DFS (HR = 0.80, 95% CI [0.62, 1.04], p = 0.092). In subgroup analyses, the results were not consistent across the subgroups that were divided based on the publication year (before 2018: HR = 1.92, 95% CI [1.34–2.75], p < 0.001; after 2018: HR = 1.42, 95% CI [0.70–2.89], p = 0.335). Moreover, PD-L1 expression in TCs significantly correlated with the AJCC TNM stage of CCA (OR = 0.52, 95% CI [0.27, 0.99], p = 0.09).

Conclusion: Our meta-analyses revealed that PD-L1 expressed in TCs was significantly correlated with the AJCC TNM stage of CCA. Based on the included studies, we found that PD-L1 indeed expressed in both TCs and ICs in CCA patients, raising the possibility of the use of anti-PD-1/PD-L1 therapy for CCA patients. In contrast, expression of PD-L1 did not seem to be associated with patient outcome in our study. The prognostic role of PD-L1 in CCA demands further investigation.

Clinicopathological evidence of hepatitis B virus infection in the development of gastric adenocarcinoma

Gastric cancer (GC) is one of the infection-related cancers. Helicobacter pylori and Epstein-Barr virus (EBV) were established risk factors for GC. Recently, there are several reports showing the inconsistent association between hepatitis B virus (HBV) infection and the development of GC. To explore the relationship between HBV infection and the development of GC, we designed a meta-analysis of previous epidemiological studies, a hospital-based case-control study, followed by an immunohistochemistry (IHC) assay of HBV-exposed GC samples. We found that HBV infection was associated with an increased risk of GC based on the meta-analysis. No significant association between HBV infection and GC was detected according to our hospital-based case-control study. Histological examination showed that the gastric epithelium positive for HBx demonstrated a higher nuclear-cytoplasmic ratio compared to those HBx-negative cells. HBx and HBcAg were expressed more in tumors than those in normal counterparts in HBV-exposed subjects, and PD-L1 was lower in GC tissues from HBV carriers than those in HBV clearances. In conclusion, HBV infection may contribute to a higher risk for GC based on the meta-analysis and to the morphological atypia of gastric epithelium by the histological assessment, and GC patients among HBV carriers showed lower expression of PD-L1 may lose the chance for immune checkpoint blockade therapy.

Immune checkpoints and cancer in the immunogenomics era

Immune checkpoints have been the subject of a wave of new studies. Among these checkpoints are tytotoxic T-lymphocyte-associated antigen 4, checkpoints programmed death-1 and programmed death-ligand 1; their blockades have been approved by the Food and Drug Administration for therapy of melanoma and other types of cancers. Immunogenomics, which combines the latest nucleic acid sequencing strategy with immunotherapy, provides precise information about genomic alterations (e.g. mutations) and enables a paradigm shift of immune checkpoint therapy from tumor types to molecular signatures. Studying these critical checkpoints in relation to genomic mutations and neoantigens has produced groundbreaking results. This article examines these studies and delves into the relationships between immune checkpoint blockade and tumors harboring certain genomic mutations. Moreover, this article reviews recent studies on resistance to immune checkpoint therapy.

Frequency and prognostic significance of isocitrate dehydrogenase 1 mutations in cholangiocarcinoma: a systematic literature review

BACKGROUND

The recognition of distinct molecular subgroups within cholangiocarcinoma (CC), along with the increasing availability of targeted therapies, suggests that further characterization of the prevalence and prognosis of frequently occurring subgroups may assist with the development of more effective treatment approaches for the management of CC. A systematic review was performed to investigate the prevalence of isocitrate dehydrogenase 1 (IDH1) mutations (mIDH1) in patients with CC, the possible clinical and prognostic significance of mIDH1, and the presence of co-mutations in tumors with mIDH1.

METHODS

This review was conducted using the Cochrane dual-reviewer methodology and the Preferred Reporting Items for Systematic Reviews and Meta-Analyses protocol (PRISMA-P) guidelines. Searches were performed in Embase, MEDLINE, the Cochrane Central Trials Register and Database of Systematic Reviews, and other Cochrane Library assets using terms for CC and mIDH1 with no language or date restrictions for articles published up to December 31, 2017. Searches were also performed of abstracts presented at the following conferences in 2016 and 2017: American Society of Clinical Oncology (ASCO), ASCO-Gastrointestinal Cancers Symposium (ASCO-GI), the European Society for Medical Oncology (ESMO), and ESMO-Asia. Screening was performed separately by two reviewers and cross-checked. Any discrepancies between reviewers were resolved by a senior researcher. Data from all selected references were recorded in a data extraction grid.

RESULTS

A total of 46 publications met the inclusion criteria and were included in the systematic review. Of these publications, 45 reported the frequency of mIDH1 among a total sample of 5,393 patients with CC. mIDH1 was enriched in intrahepatic CC (ICC), with 552 (13.1%; 95% CI, 12.1-14.2) of the 4,214 patients with ICC having the mutation compared with 9 (0.8%; 95% CI, 0.4-1.5%) of the 1,123 patients with extrahepatic CC (ECC). The percentage of females with mIDH1 CC (66.2%; 95% CI, 57.7-73.7%) was higher than in the overall CC population (44.4%). The frequency of mIDH1 in patients with ICC reported in individual studies ranged from 4.5-55.6%, and a significantly higher frequency was reported in non-Asian centers compared with Asian centers (weighted mean, 16.5% vs. 8.8%; P<0.001). The prevalence of mIDH1 in patients with ICC at USA centers was 18.0% (95% CI, 16.4-19.8%). Eleven publications reported the prevalence of co-mutations in patients with mIDH1 ICC, with the most frequent being AT-rich interactive domain-containing protein 1A (ARID1A) (22.0%), BRCA1-associated protein 1 (BAP1) (15.5%), and PBRM1 (13.3%). Eight publications investigated the possible prognostic significance of mIDH1. None of the studies reported a statistically significant association between mIDH1 and overall survival (OS), progression-free survival (PFS), or time to progression.

CONCLUSIONS

This systematic review substantiates the prevalence of mIDH1 in CC and further characterizes clinical, pathologic, and genetic covariates within this sub-population. Co-mutation data may inform future studies of mechanisms of response and resistance to mIDH1-targeted therapies.

Completely resolved advanced biliary tract cancer after treatment by pembrolizumab: a report of two cases

Biliary tract cancers (BTC) represent an aggressive disease with a dismal prognosis. Gemcitabine in combination with cisplatin is the standard first-line palliative treatment for advanced BTC. There is no established treatment following progression on gemcitabine-cisplatin. In this article, we present two cases for individuals with advanced BTC who were treated with pembrolizumab and the tumors have completely resolved.

Concurrent Expression of CD47 and CD44 in Colorectal Cancer Promotes Malignancy

CD47 activates signal regulatory protein alpha expressed on macrophages and suppresses its phagocytic ability; therefore, CD47 is drawing attention as an immune checkpoint in the innate immune system. Expression of CD47 in cancer is thought to allow cancer cells to escape antitumor immunity of the innate immune system. In this study, expression of CD47 was examined by immunostaining in colorectal cancer (CRC) and compared with the expression of CD44, which is a marker for cancer stem cells. In 95 cases of stage II-IV CRC, CD47 and CD44 showed overexpression in 82 and 80 cases, respectively. Both expression levels correlated with distant metastasis. Moreover, the expression of CD47 and CD44 in each case showed a significant correlation. In stage III cases, disease-free survival of cases showing high expression of CD47 and CD44 was worse than that of the cases with low expression. Furthermore, 3 of the stage IV cases were administered nivolumab, a checkpoint inhibitor of the acquired immune system, and 2 patients showed recurrence thereafter. All recurrent tumors highly expressed CD47 and CD44 and showed the epithelial-mesenchymal transition (EMT) phenotype. Our results suggest that CD47 promotes the malignancy of CRC in association with EMT and enhances the stemness of cancer cells. Moreover, our study suggests that CD47 and CD44 are involved in imparting resistance to programmed cell death (PD)-1/PD-ligand 1 inhibitors.

The Role of BRCA Testing in Hereditary Pancreatic and Prostate Cancer Families

Beyond breast and ovarian cancers, mutations in the BRCA1 and BRCA2 genes increase risks for pancreatic and prostate cancers and contribute to the prevalence of these cancers. Mutations in a number of other genes have also been shown to increase the risk for these cancers as well. Genetic testing is playing an increasingly important role in the treatment of patients with pancreatic and prostate cancer and is now recommended for all patients with pancreatic or metastatic prostate cancer, as well as patients with high Gleason grade prostate cancer and a remarkable family history. Identification of an inherited mutation can direct evaluation of the patient for other cancer risks as well as identification and management of disease in at-risk relatives. Growing evidence suggests improved responses to PARP inhibitors and other therapies in patients with mutations in the BRCA and other DNA repair genes. Although more work must be done to clarify the prevalence and penetrance of mutations in genes other than BRCA1 and BRCA2 in patients with pancreatic and prostate cancer, in most cases, testing is now being done with a panel of multiple genes. Because of the complexities in panel testing and the increased likelihood of finding variants of uncertain significance, pre- and post-test genetic counseling are essential.

Low frequency of mismatch repair deficiency in gallbladder cancer

Background

DNA mismatch repair (MMR) deficiency is a major pathway of genomic instability in cancer. It leads to the accumulation of numerous mutations predominantly at microsatellite sequences, a phenotype known as microsatellite instability (MSI). MSI tumors have a distinct clinical behavior and commonly respond well to immune checkpoint blockade, irrespective of their origin. Data about the prevalence of MSI among gallbladder cancer (GBC) have been conflicting. We here analyzed a well-characterized cohort of 69 Western-world GBCs.

Methods

We analyzed the mononucleotide MSI marker panel consisting of BAT25, BAT26, and CAT25 to determine the prevalence of MMR deficiency-induced MSI.

Results

MSI was detected in 1/69 (1.4%) of analyzed GBCs. The detected MSI GBC had a classical histomorphology, i.e. of acinar/tubular/glandular pancreatobiliary phenotype, and showed nuclear expression of all four MMR proteins MLH1, MSH2, MSH6, and PMS2. The MSI GBC patient showed a prolonged overall survival, despite having a high tumor stage at diagnosis. The patient had no known background or family history indicative of Lynch syndrome.

Conclusions

Even though the overall number of MSI tumors is low in GBC, the potentially therapeutic benefit of checkpoint blockade in the respective patients may justify MSI analysis of GBC.

Electronic supplementary material

The online version of this article (10.1186/s13000-019-0813-5) contains supplementary material, which is available to authorized users.

Role of tumor gene mutations in treatment response to immune checkpoint blockades

Early studies shed light on the immune suppression of immune checkpoint molecules in the cancer microenvironment, with later studies applying immune checkpoint blockade (ICB) in treatment of various malignancies. Despite the encouraging efficacy of ICBs in a substantial subset of cancer patients, the treatment response varies. Gene mutations of both tumor cells and immune cells in the tumor microenvironment have recently been identified as potential predictors of the ICB response. Recent developments in gene expression profiling of tumors have allowed identification of a panel of mutated genes that may affect tumor cell response to ICB treatment. In this review, we discuss the association of the ICB response with gene expression and mutation profiles in tumor cells, which it is hoped will help to optimize the clinical application of ICBs in cancer patients.

BRCA1 mRNA expression modifies the effect of T cell activation score on patient survival in breast cancer

Background

Effector CD8⁺ T cell activation and its cytotoxic function to eradicate tumor cells depend on the T cell recognition of tumor neoantigens, and are positively associated with improved survival in breast cancer. Tumor suppressor BRCA1 and cell cycle regulator CCND1 play a critical role in maintaining genome integrity and tumorigenesis, respectively. However, it is still unclear how BRCA1 and CCND1 expression levels affect the effect of T cell activation on breast cancer patient survival.

Methods

The interactions between T cell activation status and either BRCA1 or CCND1 expression were evaluated using Kaplan-Meier survival curves and multivariate Cox regression models in a public dataset with 1088 breast cancer patients.

Results

Among the patients with low BRCA1 or CCND1 expression, the Activation group showed better overall survival than the Exhaustion group. Adjusted hazards ratios were 0.43 (95% CI: 0.20–0.93) in patients with a low BRCA1 level, and 0.39 (95% CI: 0.19–0.81) in patients with a low CCND1 level, respectively. There was a significant trend in both subgroups (p-trend = 0.011 in the low BRCA1 group, and p-trend = 0.009 in the low CCND1 group). In contrast, there is no significant association in patients with either high BRCA1 or high CCND1 levels. There is a significant interaction between T cell activation status and BRCA1 level (p = 0.009), but not between T cell activation status and CCND1 level (p = 0.135).

Conclusions

BRCA1 expression modified the effect of T cell activation status on patient survival in breast cancer, suggesting that the existence of neoantigens and the enhancement of neoantigen presentation in combination with immune checkpoint blockade may have synergistic effects on patient outcome.

HHLA2 in intrahepatic cholangiocarcinoma: an immune checkpoint with prognostic significance and wider expression compared with PD-L1

Background

Intrahepatic cholangiocarcinoma (ICC) is a highly mortal malignancy with limited therapeutic options. Immunotherapies targeting PD-1/PD-L1 pathway represent a promising treatment for ICC. However, PD-L1 expression and microsatellite instability are not common in ICC. This study aimed to investigate whether HHLA2, a newly identified B7 family immune checkpoint for T cells, could be a therapeutic target next to PD-L1 in ICC.

Methods

Expression levels of PD-L1 and HHLA2 as well as infiltrations of CD3+, CD8+, CD4 + Foxp3+, CD68+, CD163+ and CD20+ cells were evaluated by immunohistochemistry in 153 resected ICC samples. Comprehensive comparisons were made between PD-L1 and HHLA2 in terms of the expression rates, clinicopathological features and infiltrations of different immune cells. The expression level and prognostic significance of HHLA2 were further validated in an independent cohort.

Results

Expression of HHLA2 is more frequent than PD-L1 in ICC (49.0% vs 28.1%). Co-expression of both immune checkpoints was infrequent (13.1%) and 50% PD-L1 negative cases were with elevated HHLA2. HHLA2 overexpression was associated with sparser CD3+ tumor infiltrating lymphocytes (TILs), CD8+ TILs and a higher CD4 + Foxp3+/CD8+ TIL ratio, whereas PD-L1 expression was associated with prominent T cells and CD163+ tumor associated macrophages infiltrations. PD-L1 failed to stratify overall survival (OS) but HHLA2 was identified as an independent prognostic indicator for OS in two independent cohorts.

Conclusions

Compared with PD-L1, HHLA2 is more prevalent and possesses more explicit prognostic significance, which confer the rationale for HHLA2 as a potential immunotherapeutic target next to PD-L1 for ICC patients.

Electronic supplementary material

The online version of this article (10.1186/s40425-019-0554-8) contains supplementary material, which is available to authorized users.

Programmed cell death ligand 1 (PD-L1, CD274) in cholangiocarcinoma - correlation with clinicopathological data and comparison of antibodies

BACKGROUND

Cholangiocarcinoma (CCA) may arise in the intra- or extrahepatic biliary tract and is associated with a poor prognosis. Despite recent advances, to date there is still no established targeted therapeutic approach available. Non-surgical therapeutic agents are urgently needed, as most patients are non-eligible to surgical resection. Anti-PD-L1 therapy prevents cancer cells from evading the immune system and has emerged as a new treatment option in several cancer entities. Recently, PD-L1 expression has been analyzed in comparably small CCA patient cohorts. However, a systematic validation of different PD-L1 antibodies has not been performed in CCA so far.

METHODS

We stained a tissue microarray consisting of 170 patients, including 72 intrahepatic cholangiocarcinomas (iCCAs), 57 perihilar cholangiocarcinomas (pCCAs) and 41 distal cholangiocarcinomas (dCCAs) by immunohistochemistry and evaluated PD-L1 positivity in tumor and stromal cells. We analyzed three different PD-L1 antibodies (clones 28-8, SP142, and SP263) that are frequently used and recommended for predictive diagnostic testing in other cancer types.

RESULTS

For PD-L1 antibody clone SP263, 5% of iCCAs, 4% of pCCAs and 3% of dCCAs exhibited PD-L1 expression on tumor cells, thereby showing the highest frequencies of PD-L1 positivity. Accordingly, highest PD-L1 positivity rates of stromal cells with 31% in iCCA, 40% in pCCA and 61% in dCCA were detected for clone SP263. Agreement of PD-L1 positivity in tumor cells was moderate for clone 28-8 and SP263 (κ = 0.44) and poor between 28-8 and SP142 (κ = 0.13), as well as  SP142 and SP263 (κ = 0.11), respectively. Statistical analyses of PD-L1 expression (clone SP263) on tumor cells with clinicopathological data revealed a positive correlation with shortened overall survival in CCA patients.

CONCLUSIONS

Selection of appropriate PD-L1 antibodies and careful evaluation of immunohistochemical staining patterns have a significant impact on PD-L1 testing in CCA. Clinical trials are necessary to investigate the putative beneficial effects of PD-L1 targeted immunotherapy in CCA patients.

Ramucirumab Plus Pembrolizumab in Patients with Previously Treated Advanced or Metastatic Biliary Tract Cancer: Nonrandomized, Open-Label, Phase I Trial (JVDF)

LESSONS LEARNED

Ramucirumab plus pembrolizumab revealed no unexpected safety findings in patients with advanced or metastatic biliary tract cancer, which is consistent with reports of other tumor cohorts within this phase Ia/b trial.Ramucirumab plus pembrolizumab did not demonstrate an improvement in overall survival when compared with historical controls in biomarker unselected, heavily pretreated patients with advanced or metastatic biliary tract cancer.Patients with programmed death-ligand 1 (PD-L1)-positive tumors had improved overall survival compared with patients with PD-L1-negative disease.

BACKGROUND

Few treatment options exist for patients with advanced biliary tract cancer (BTC) following progression on gemcitabine-cisplatin. Preclinical evidence suggests that simultaneous blockade of vascular endothelial growth factor receptor 2 (VEGFR-2) and programmed death 1 (PD-1) or programmed death-ligand 1 (PD-L1) enhances antitumor effects. We assessed the safety and efficacy of ramucirumab, an IgG1 VEGFR-2 antagonist, with pembrolizumab, an IgG4 PD-1 antagonist, in biomarker-unselected patients with previously treated advanced or metastatic BTC.

METHODS

Patients had previously treated advanced or metastatic adenocarcinoma of the gallbladder, intrahepatic and extrahepatic bile ducts, or ampulla of Vater. Ramucirumab 8 mg/kg was administered intravenously on days 1 and 8 with intravenous pembrolizumab 200 mg on day 1 every 3 weeks. The primary endpoint was safety and tolerability of the combination. Secondary endpoints included objective response rate (ORR), progression-free survival (PFS), and overall survival (OS).

RESULTS

Twenty-six patients were treated at 12 centers in five countries. Hypertension was the most common grade 3 treatment-related adverse event (TRAE), occurring in five patients. One patient experienced a grade 4 TRAE (neutropenia), and no treatment-related deaths occurred. Objective response rate was 4%. Median progression-free survival and overall survival were 1.6 months and 6.4 months, respectively.

CONCLUSION

Ramucirumab-pembrolizumab showed limited clinical activity with infrequent grade 3-4 TRAEs in patients with biomarker-unselected progressive BTC.

Mismatch repair deficiency is a rare but putative therapeutically relevant finding in non-liver fluke associated cholangiocarcinoma

Background

A major molecular pathway of genetic instability in cancer is DNA mismatch repair deficiency. High-level microsatellite instability (MSI-H) is currently the best predictor of responsiveness towards immune checkpoint blockade. Data about the prevalence of high-level microsatellite instability in cholangiocarcinoma (CCA) has been conflicting.

Methods

We employed a cohort comprising 308 Western-world, non-liver fluke-associated CCAs (159 intrahepatic, 106 perihilar, and 43 distal). We analysed the mononucleotide microsatellite instability marker panel consisting of BAT25, BAT26, and CAT25 and detected MSI-H in 4/308 CCAs (1.3%).

Results

Patients affected by MSI-H CCA had mostly an atypical histomorphology (p = 0.004), showed a longer overall survival, although having a high tumour stage, and were of younger age. Correlation analysis of microsatellite instability status with tumour-infiltrating immune cells, MHC I, and PD-L1 expression in the same cholangiocarcinoma cohort showed higher numbers of CD8 + T cells, FOXP3 + regulatory T cells, CD20 + B cells and high or at least moderate MHC I expression levels in MSI-H CCAs.

Conclusions

Even though the overall number of MSI-H CCAs is low, the dismal prognosis of the disease and the therapeutic option of immune checkpoint blockade in the respective patients justify MSI testing of cholangiocarcinoma, particularly in younger patients showing an atypical histomorphology.

Pancreatic cancer as a sentinel for hereditary cancer predisposition

BACKGROUND

Genes associated with hereditary breast and ovarian cancer (HBOC) and colorectal cancer (CRC) predisposition have been shown to play a role in pancreatic cancer susceptibility. Growing evidence suggests that pancreatic cancer may be useful as a sentinel cancer to identify families that could benefit from HBOC or CRC surveillance, but to date pancreatic cancer is only considered an indication for genetic testing in the context of additional family history.

METHODS

Preliminary data generated at the Huntsman Cancer Hospital (HCH) included variants identified on a custom 34-gene panel or 59-gene panel including both known HBOC and CRC genes for respective sets of 66 and 147 pancreatic cancer cases, unselected for family history. Given the strength of preliminary data and corresponding literature, 61 sequential pancreatic cancer cases underwent a custom 14-gene clinical panel. Sequencing data from HCH pancreatic cancer cases, pancreatic cancer cases of the Cancer Genome Atlas (TCGA), and an unselected pancreatic cancer screen from the Mayo Clinic were combined in a meta-analysis to estimate the proportion of carriers with pathogenic and high probability of pathogenic variants of uncertain significance (HiP-VUS).

RESULTS

Approximately 8.6% of unselected pancreatic cancer cases at the HCH carried a variant with potential HBOC or CRC screening recommendations. A meta-analysis of unselected pancreatic cancer cases revealed that approximately 11.5% carry a pathogenic variant or HiP-VUS.

CONCLUSION

With the inclusion of both HBOC and CRC susceptibility genes in a panel test, unselected pancreatic cancer cases act as a useful sentinel cancer to identify asymptomatic at-risk relatives who could benefit from relevant HBOC and CRC surveillance measures.

Microsatellite Instability Occurs Rarely in Patients with Cholangiocarcinoma: A Retrospective Study from a German Tertiary Care Hospital

Immune-modulating therapy is a promising therapy for patients with cholangiocarcinoma (CCA). Microsatellite instability (MSI) might be a favorable predictor for treatment response, but comprehensive data on the prevalence of MSI in CCA are missing. The aim of the current study was to determine the prevalence of MSI in a German tertiary care hospital. Formalin-fixed paraffin-embedded tissue samples, obtained in the study period from 2007 to 2015 from patients with CCA undergoing surgical resection with curative intention at Johann Wolfgang Goethe University hospital, were examined. All samples were investigated immunohistochemically for the presence of MSI (expression of MLH1, PMS2, MSH2, and MSH6) as well as by pentaplex polymerase chain reaction for five quasimonomorphic mononucleotide repeats (BAT-25, BAT-26, NR-21, NR-22, and NR-24). In total, 102 patients were included, presenting intrahepatic (n = 35, 34.3%), perihilar (n = 42, 41.2%), and distal CCA (n = 25, 24.5%). In the immunohistochemical analysis, no loss of expression of DNA repair enzymes was observed. In the PCR-based analysis, one out of 102 patients was found to be MSI-high and one out of 102 was found to be MSI-low. Thus, MSI seems to appear rarely in CCA in Germany. This should be considered when planning immune-modulating therapy trials for patients with CCA.

Desmoplastic Tumor Microenvironment and Immunotherapy in Cholangiocarcinoma

Cholangiocarcinoma (CCA) is a dismal disease which often is diagnosed at a late stage where the tumor is locally advanced, metastatic, and, as a result, is associated with low resectability. The heterogeneity of this cancer type is a major reason why the majority of patients fail to respond to therapy, and surgery remains their only curative option. Among patients who undergo surgical intervention, such tumors typically recur in 50% of cases within 1year. Thus, CCA is among the most aggressive and chemoresistant malignancies. CCA is characterized by marked tumor reactive stroma, a fibrogenic connective tissue which surrounds and infiltrates the tumor epithelium. This desmoplastic environment presents a clinical challenge, limiting drug delivery and supporting the growth of the tumor mass. In this review we attempt to highlight key pathways involved in cell to cell communication between the tumor epithelium and stroma, the immune components, and opportunities for novel strategies to improve patient outcome.

Cellular vaccination of MLH1-/- mice - an immunotherapeutic proof of concept study

Mismatch-repair deficiency (MMR-D) is closely linked to hypermutation and accordingly, high immunogenicity. MMR-D-related tumors thus constitute ideal vaccination targets for both therapeutic and prophylactic approaches. Herein, the prophylactic and therapeutic impact of a cellular vaccine on tumor growth and tumor-immune microenvironment was studied in a murine MLH1^-/- knockout mouse model. Prophylactic application of the lysate (+/- CpG ODN 1826) delayed tumor development, accompanied by increased levels of circulating T cell numbers. Therapeutic application of the vaccine prolonged overall survival (median time: 11.5 (lysate) and 12 weeks (lysate + CpG ODN) vs. 3 weeks (control group), respectively) along with reduced tumor burden, as confirmed by PET/CT imaging and immune stimulation (increased CD3⁺CD8⁺ T - and NK cell numbers, reduced levels of TIM-3⁺ cells in both treatment groups). Coding microsatellite analysis of MMR-D-related target genes revealed increased mutational load upon vaccination (total mutation frequency within 28 genes: 28.6% vaccine groups vs. 14.9% control group, respectively). Reactive immune cells recognized autologous tumor cells, but also NK cells target YAC-1 in IFNγ ELISpot and, even more importantly, in functional kill assays. Assessment of tumor microenvironment revealed infiltration of CD8⁺ T-cells and granulocytes, but also upregulation of immune checkpoint molecules (LAG-3, PD-L1). The present study is the first reporting in vivo results on a therapeutic cellular MMR-D vaccine. Vaccination-induced prolonged survival was achieved in a clinically-relevant mouse model for MMR-D-related diseases by long-term impairment of tumor growth and this could be attributed to re-activated immune responses.

Microsatellite instability status predicts response to anti-PD-1/PD-L1 therapy regardless the histotype: A comment on recent advances

It is well-known that somatic mutations resulting in increased number of neoantigens (“immunogenic antigens”) may enhance anti-tumor immune cell reaction. Also, high tumor mutation burden (load) [TML] is associated with improved response, durable clinical benefits and better outcome if a cancer is treated with immune check point inhibitors [anti-programmed cell death protein 1/programmed death-ligand 1 (anti-PD-1/PD-L1) drugs] [1]. A subset of colorectal carcinomas (CRC) and other cancers characterized by mismatch repair deficiency (MMR) and/or microsatellite instability high (MSI-H) profiles may be particularly sensitive to the PD-1/PD-L1 blockade with immune check point inhibitors due to the common PD-L1/PD-L1 expression [2-9]. Several therapeutic antibodies inhibiting either PD-1 (nivolumab, pembrolizumab) or PD-L1 (MPDL3280A, Medi4736, BMS-936559) have been developed and approved for the treatment of various malignancies including malignant melanoma, non-small cell lung carcinoma, renal cell carcinoma, bladder carcinoma, Merkel cell carcinoma, and classical Hodgkin lymphoma [10]. A pivotal phase 2 study by Le et al. [11] highlighted the importance of mismatch-repair status in prediction of the clinical benefit of immune checkpoint blockade with pembrolizumab (anti-PD-1 drug) [11]. The study included 41 patients with progressive cancers of both CRC and non-colorectal origins and known MSI status. For CRC patients, the objective response rate and progression-free survival rate were 40% and 78%, respectively for mismatch repair-deficient tumors and 0% and 11% for mismatch repair-proficient CRCs. A novel study by Le et al. [12] (ClinicalTrials.gov number, NCT01876511) represents an extended analysis on the efficacy of PD-1 blockade in patients with advanced mismatch repair-deficient cancers. The study included 86 patients with 12 different histologic cancer subtypes and proved mismatch repair-deficiency status assessed by either polymerase chain reaction (PCR) or immunohistochemistry. The data presented in this study indicate objective radiographic responses in 53% of patients while complete responses were achieved in 21% of patients. Based on this and previous data, on May 23, 2017, the U.S. Food and Drug Administration (FDA) granted accelerated approval to anti-PD-L1 drug pembrolizumab (KEYTRUDA®, Merck & Co.) for adult and pediatric patients with unresectable/metastatic MSI-H/MMR deficient solid tumors (regardless the histotype) that have progressed following prior treatment and without satisfactory alternative treatment modalities. The approval also covered MSI-H CRC patients who progressed following treatment with a classic cytotoxic therapy (fluoropyrimidine, oxaliplatin, and irinotecan). Taken together, these results revolutionize the cancer treatment paradigm as for the first time the cancer treatment was based solely on the molecular characteristics of cancer (in this case microsatellite instability/MSI/ status) regardless the tumor morphology (histotype). This appears to be “the FDA’s first tissue/site-agnostic approval”. Certainly, there are still ongoing but unresolved issues regarding these treatments including other merging predictive biomarkers (optimization of PD-L1 and PD-1 evaluation, e.g. tumor versus immune cell expression; cutoffs for positivity; selection of detection antibodies), tumor mutational load and the tumor neoantigen heterogeneity/specificity [13-15]. Further studies should also elucidate the mechanisms of recently described resistance to immune checkpoint inhibitors [16-18].