ESMO recommendations on microsatellite instability testing for immunotherapy in cancer, and its relationship with PD-1/PD-L1 expression and tumour mutational burden: a systematic review-based approach

BACKGROUND

Cancers with a defective DNA mismatch repair (dMMR) system contain thousands of mutations most frequently located in monomorphic microsatellites and are thereby defined as having microsatellite instability (MSI). Therefore, MSI is a marker of dMMR. MSI/dMMR can be identified using immunohistochemistry to detect loss of MMR proteins and/or molecular tests to show microsatellite alterations. Together with tumour mutational burden (TMB) and PD-1/PD-L1 expression, it plays a role as a predictive biomarker for immunotherapy.

METHODS

To define best practices to implement the detection of dMMR tumours in clinical practice, the ESMO Translational Research and Precision Medicine Working Group launched a collaborative project, based on a systematic review-approach, to generate consensus recommendations on the: (i) definitions related to the concept of MSI/dMMR; (ii) methods of MSI/dMMR testing and (iii) relationships between MSI, TMB and PD-1/PD-L1 expression.

RESULTS

The MSI-related definitions, for which a consensus frame-work was used to establish definitions, included: 'microsatellites', 'MSI', 'DNA mismatch repair' and 'features of MSI tumour'. This consensus also provides recommendations on MSI testing; immunohistochemistry for the mismatch repair proteins MLH1, MSH2, MSH6 and PMS2 represents the first action to assess MSI/dMMR (consensus with strong agreement); the second method of MSI/dMMR testing is represented by polymerase chain reaction (PCR)-based assessment of microsatellite alterations using five microsatellite markers including at least BAT-25 and BAT-26 (strong agreement). Next-generation sequencing, coupling MSI and TMB analysis, may represent a decisive tool for selecting patients for immunotherapy, for common or rare cancers not belonging to the spectrum of Lynch syndrome (very strong agreement). The relationships between MSI, TMB and PD-1/PD-L1 expression are complex, and differ according to tumour types.

CONCLUSIONS

This ESMO initiative is a response to the urgent questions raised by the growing success of immunotherapy and provides also important insights on the relationships between MSI, TMB and PD-1/PD-L1.

Comprehensive characterisation of pancreatic ductal adenocarcinoma with microsatellite instability: histology, molecular pathology and clinical implications

OBJECTIVE

Recently, tumours with microsatellite instability (MSI)/defective DNA mismatch repair (dMMR) have gained considerable interest due to the success of immunotherapy in this molecular setting. Here, we aim to clarify clinical-pathological and/or molecular features of this tumour subgroup through a systematic review coupled with a comparative analysis with existing databases, also providing indications for a correct approach to the clinical identification of MSI/dMMR pancreatic ductal adenocarcinoma (PDAC).

DESIGN

PubMed, SCOPUS and Embase were searched for studies reporting data on MSI/dMMR in PDAC up to 30 November 2019. Histological and molecular data of MSI/dMMR PDAC were compared with non-MSI/dMMR PDAC and with PDAC reference cohorts (including SEER database and The Cancer Genome Atlas Research Network - TCGA project).

RESULTS

Overall, 34 studies with 8323 patients with PDAC were included in the systematic review. MSI/dMMR demonstrated a very low prevalence in PDAC (around 1%-2%). Compared with conventional PDAC, MSI/dMMR PDAC resulted strongly associated with medullary and mucinous/colloid histology (p<0.01) and with a KRAS/TP53 wild-type molecular background (p<0.01), with more common JAK genes mutations. Data on survival are still unclear.

CONCLUSION

PDAC showing typical medullary or mucinous/colloid histology should be routinely examined for MSI/dMMR status using specific tests (immunohistochemistry, followed by MSI-PCR in cases with doubtful results). Next-generation sequencing (NGS) should be adopted either where there is limited tissue or as part of NGS tumour profiling in the context of precision oncology, acknowledging that conventional histology of PDAC may rarely harbour MSI/dMMR.

Artificial intelligence in oncology: current applications and future perspectives

Artificial intelligence (AI) is concretely reshaping the landscape and horizons of oncology, opening new important opportunities for improving the management of cancer patients. Analysing the AI-based devices that have already obtained the official approval by the Federal Drug Administration (FDA), here we show that cancer diagnostics is the oncology-related area in which AI is already entered with the largest impact into clinical practice. Furthermore, breast, lung and prostate cancers represent the specific cancer types that now are experiencing more advantages from AI-based devices. The future perspectives of AI in oncology are discussed: the creation of multidisciplinary platforms, the comprehension of the importance of all neoplasms, including rare tumours and the continuous support for guaranteeing its growth represent in this time the most important challenges for finalising the 'AI-revolution' in oncology.

Molecular Tumor Boards in Clinical Practice

Next-generation sequencing (NGS) application in clinical practice requires the implementation of molecular tumor boards (MTBs). Starting from a systematic review of literature, we discuss the MTB-related key points: MTB aims and composition, types of tumors to discuss, types of molecular analyses, methods for classifying actionability, appropriate turnaround time, and cost management.

Assessing the quality of studies in meta-research: Review/guidelines on the most important quality assessment tools

Systematic reviews and meta-analyses pool data from individual studies to generate a higher level of evidence to be evaluated by guidelines. These reviews ultimately guide clinicians and stakeholders in health-related decisions. However, the informativeness and quality of evidence synthesis inherently depend on the quality of what has been pooled into meta-research projects. Moreover, beyond the quality of included individual studies, only a methodologically correct process, in relation to systematic reviews and meta-analyses themselves, can produce a reliable and valid evidence synthesis. Hence, quality of meta-research projects also affects evidence synthesis reliability. In this overview, the authors provide a synthesis of advantages and disadvantages and main characteristics of some of the most frequently used tools to assess quality of individual studies, systematic reviews, and meta-analyses. Specifically, the tools considered in this work are the Newcastle-Ottawa scale (NOS) and the Strengthening the Reporting of Observational Studies in Epidemiology (STROBE) for observational studies, the Consolidated Standards of Reporting Trials (CONSORT), the Jadad scale, the Cochrane risk of bias tool 2 (RoB2) for randomized controlled trials, the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) and the Assessment of Multiple Systematic Reviews 2 (AMSTAR2), and AMSTAR-PLUS for meta-analyses. WHAT IS ALREADY KNOWN?: The informativeness and quality of evidence synthesis inherently depend on the quality of what has been pooled into meta-research projects. Beyond the quality of included individual studies, only a methodologically correct process, in relation to systematic reviews and meta-analyses themselves, can produce a reliable and valid evidence synthesis. WHAT IS NEW?: In this overview, the authors provide a synthesis of advantages and disadvantages and main characteristics of some of the most frequently used tools to assess quality of individual studies, systematic reviews, and meta-analyses. POTENTIAL IMPACT: This overview serves as a starting point and a brief guide to identify and understand the main and most frequently used tools for assessing the quality of studies included in meta-research. The authors here share their experience in publishing several meta-research-related articles covering different areas of medical sciences.

Pancreatic Ductal Adenocarcinoma and Its Variants

Pancreatic cancer represents the seventh leading cause of cancer death in the world, responsible for more than 300,000 deaths per year. The most common tumor type among pancreatic cancers is pancreatic ductal adenocarcinoma, an infiltrating neoplasm with glandular differentiation that is derived from pancreatic ductal tree. Here we present and discuss the most important macroscopic, microscopic, and immunohistochemical characteristics of this tumor, highlighting its key diagnostic features. Furthermore, we present the classic features of the most common variants of pancreatic ductal adenocarcinoma. Last, we summarize the prognostic landscape of this highly malignant tumor and its variants.

Pancreatic undifferentiated carcinoma with osteoclast-like giant cells is genetically similar to, but clinically distinct from, conventional ductal adenocarcinoma

Undifferentiated carcinoma of the pancreas with osteoclast-like giant cells (UCOGC) is currently considered a morphologically and clinically distinct variant of pancreatic ductal adenocarcinoma (PDAC). In this study, we report clinical and pathological features of a series of 22 UCOGCs, including the whole exome sequencing of eight UCOGCs. We observed that 60% of the UCOGCs contained a well-defined epithelial component and that patients with pure UCOGC had a significantly better prognosis than did those with an UCOGC with an associated epithelial neoplasm. The genetic alterations in UCOGC are strikingly similar to those known to drive conventional PDAC, including activating mutations in the oncogene KRAS and inactivating mutations in the tumor suppressor genes CDKN2A, TP53, and SMAD4. These results further support the classification of UCOGC as a PDAC variant and suggest that somatic mutations are not the determinants of the unique phenotype of UCOGC. Copyright © 2017 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

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, I(2) = 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, I(2) = 19%) and cancer recurrence (studies = 10; HR = 1.93, 95%CI = 1.22-3.05, I(2) = 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.

Different prognostic roles of tumor suppressor gene BAP1 in cancer: A systematic review with meta-analysis

Biallelic inactivation of the tumor suppressor gene BRCA1-associated protein 1 (BAP1) has been demonstrated in several cancers, but its prognostic role has not been completely explained. We aimed to investigate the risk associated with loss of BAP1 (BAP1-) for all-cause mortality, cancer-specific mortality and recurrence of disease in subjects with cancer. PubMed and SCOPUS were searched from database inception until 09/15/2015 without language restrictions. Prospective studies reporting data on prognostic parameters in subjects with cancer, comparing participants with presence of BAP1 (BAP1+) vs. BAP1- were included. Data were summarized using risk ratios (RR) for number of deaths/recurrences and hazard ratios (HR) for time-dependent risk related to BAP1- adjusted for potential confounders. From 261 hits, 12 studies (including 13 cohorts) with 3,447 participants (BAP1-: n = 697; BAP1+: n = 2,750), with a median follow-up over 60 months, were meta-analyzed. Compared to BAP1+, BAP1- significantly increased all-cause mortality, cancer-specific mortality and risk of recurrence in all the tumor types analyzed, except for mesothelioma, in which the presence of BAP1 mutations correlates with a better prognosis. Furthermore, we demonstrated that BAP1 mutated colorectal and renal carcinomas are associated with high-tumor grading (P < 0.0001), and that BAP1 mutated is more common in women than in men (P < 0.0001). In conclusion, on the basis of our meta-analysis, we have demonstrated a peculiar role of BAP1 in influencing the prognosis in cancer. Thus, BAP1 could be considered as an important potential target for personalized medicine. © 2016 Wiley Periodicals, Inc.

KRAS wild-type pancreatic ductal adenocarcinoma: molecular pathology and therapeutic opportunities

Pancreatic ductal adenocarcinoma (PDAC) is a deadly disease, whose main molecular trait is the MAPK pathway activation due to KRAS mutation, which is present in 90% of cases.The genetic landscape of KRAS wild type PDAC can be divided into three categories. The first is represented by tumors with an activated MAPK pathway due to BRAF mutation that occur in up to 4% of cases. The second includes tumors with microsatellite instability (MSI) due to defective DNA mismatch repair (dMMR), which occurs in about 2% of cases, also featuring a high tumor mutational burden. The third category is represented by tumors with kinase fusion genes, which marks about 4% of cases. While therapeutic molecular targeting of KRAS is an unresolved challenge, KRAS-wild type PDACs have potential options for tailored treatments, including BRAF antagonists and MAPK inhibitors for the first group, immunotherapy with anti-PD-1/PD-L1 agents for the MSI/dMMR group, and kinase inhibitors for the third group.This calls for a complementation of the histological diagnosis of PDAC with a routine determination of KRAS followed by a comprehensive molecular profiling of KRAS-negative cases.

Prognostic implications of extranodal extension in node-positive squamous cell carcinoma of the vulva: A systematic review and meta-analysis

Squamous cell carcinoma (SCC) of the vulva is the fourth most common gynecological cancer, usually staged with the TNM or FIGO systems. Since 2009, FIGO staging has taken the extranodal extension (ENE) of lymph node metastases into account. ENE is defined as the spread of a lymph node metastasis into surrounding soft tissue. Although the TNM and FIGO systems acknowledge the importance of ENE in SCC, no comprehensive studies have analyzed the prognostic impact of this parameter. We therefore queried the PubMed and SCOPUS databases from their inception up until 04/01/2015, adopting no language restrictions: all prospective studies reporting on prognostic parameters in patients with vulvar SCC, and comparing participants with and without ENE were eligible for our analysis. Data were summarized using risk ratios (RR) for the number of deaths/recurrences and hazard ratios (HR) for the time-dependent risk related to ENE positivity, adjusting for potential confounders. Among 859 hits, 13 studies were found eligible and were included in our meta-analysis. Compared with ENE-negative (ENE-) cases, the ENE-positive (ENE+) patients had significantly higher rates of all-cause mortality (6 studies: RR = 3.18; 95%CI: 2.02-5.00, p < 0.0001, I(2) = 56%), cancer-specific mortality (3 studies: RR = 2.03; 95%CI: 1.12-3.69, p = 0.02, I(2) = 80%), and recurrence (4 studies: RR = 2.69, 95%CI: 1.61-3.76, p < 0.0001, I(2) = 57%). Using HRs after adjusting for potential confounders, ENE + carried a significantly higher risk of all-cause mortality (6 studies: HR = 3.08, 95%CI: 1.73-5.48, p < 0.0001, I(2) = 66%), and recurrence (5 studies: HR = 3.93, 95%CI: 2.33-6.62, p < 0.0001, I(2) = 28%). Our meta-analysis clarifies the prognostic significance of ENE in vulvar SCC, also pointing to its implications for gross sampling, histology and oncological staging.

PD-1, PD-L1, and CD163 in pancreatic undifferentiated carcinoma with osteoclast-like giant cells: expression patterns and clinical implications

Undifferentiated carcinoma with osteoclast-like giant cells (UCOGC), a variant of pancreatic ductal adenocarcinoma (PDAC), has a striking genetic similarity to PDAC but a significantly improved overall survival. We hypothesize that this difference could be due to the immune response to the tumor, and as such, we investigated the expression of PD-1, PD-L1, and CD163 in a series of UCOGC. To this aim, 27 pancreatic UCOGCs (11 pure and 16 PDAC-associated), 5 extrapancreatic tumors with osteoclast-like giant cells and 10 pancreatic anaplastic carcinomas were immunostained using antibodies against PD-1, PD-L1, and CD163. In pancreatic UCOGCs, PD-L1 was expressed in neoplastic cells of 17 (63%) of 27 cases, more often in cases with an associated PDAC (P = .04). Expression of PD-L1 was associated with poor prognosis, confirmed by multivariate analysis: patients with PD-L1-positive UCOGCs had a risk of all-cause mortality that was 3 times higher than did patients with PD-L1-negative UCOGCs (hazard ratio, 3.397; 95% confidence interval, 1.023-18.375; P = .034). PD-L1 expression on tumor cells was also associated with aberrant P53 expression (P = .035). PD-1 was expressed on rare lymphocytes in 12 UCOGCs (44.4%), mainly located at the tumor periphery. CD163 was expressed on histiocytes, with a diffuse and strong staining pattern in all UCOGCs. Extrapancreatic tumors with osteoclast-like giant cells showed very similar staining patterns for the same proteins. Anaplastic carcinomas have some similarities to UCOGCs, but PD-L1 has no prognostic roles. Our results may have important implications for immunotherapeutic strategies in UCOGCs; these tumors may also represent a model for future therapeutic approaches against PDAC.

Ki-67 assessment of pancreatic neuroendocrine neoplasms: Systematic review and meta-analysis of manual vs. digital pathology scoring

Ki-67 assessment is a key step in the diagnosis of neuroendocrine neoplasms (NENs) from all anatomic locations. Several challenges exist related to quantifying the Ki-67 proliferation index due to lack of method standardization and inter-reader variability. The application of digital pathology coupled with machine learning has been shown to be highly accurate and reproducible for the evaluation of Ki-67 in NENs. We systematically reviewed all published studies on the subject of Ki-67 assessment in pancreatic NENs (PanNENs) employing digital image analysis (DIA). The most common advantages of DIA were improvement in the standardization and reliability of Ki-67 evaluation, as well as its speed and practicality, compared to the current gold standard approach of manual counts from captured images, which is cumbersome and time consuming. The main limitations were attributed to higher costs, lack of widespread availability (as of yet), operator qualification and training issues (if it is not done by pathologists), and most importantly, the drawback of image algorithms counting contaminating non-neoplastic cells and other signals like hemosiderin. However, solutions are rapidly developing for all of these challenging issues. A comparative meta-analysis for DIA versus manual counting shows very high concordance (global coefficient of concordance: 0.94, 95% CI: 0.83-0.98) between these two modalities. These findings support the widespread adoption of validated DIA methods for Ki-67 assessment in PanNENs, provided that measures are in place to ensure counting of only tumor cells either by software modifications or education of non-pathologist operators, as well as selection of standard regions of interest for analysis. NENs, being cellular and monotonous neoplasms, are naturally more amenable to Ki-67 assessment. However, lessons of this review may be applicable to other neoplasms where proliferation activity has become an integral part of theranostic evaluation including breast, brain, and hematolymphoid neoplasms.

Extranodal extension in N1-adenocarcinoma of the pancreas and papilla of Vater: a systematic review and meta-analysis of its prognostic significance

The aim of the study was to investigate the prognostic role of extranodal extension (ENE) of lymph node metastasis in adenocarcinoma of the pancreas (PDAC) and papilla [cancer of the papilla of Vater (CPV)]. A PubMed and SCOPUS search from database inception until 5 January 2015 without language restrictions was conducted. Eligible were prospective studies reporting data on prognostic parameters in individuals with PDAC and/or CPV, comparing participants with the presence of ENE (ENE+) with those with intranodal extension (ENE-). Data were summarized using risk ratios for number of deaths/recurrences and hazard ratios for time-dependent risk related to ENE+, adjusted for potential confounders. ENE was found to be very common in these tumors (up to about 60% in both N1-PDAC and CPV), leading to a significant increased risk for all-cause mortality [risk ratio=1.20; 95% confidence interval (CI): 1.06-1.35, P=0.003, I(2)=44%; hazard ratio=1.415, 95% CI: 1.215-1.650, P<0.0001, I(2)=0%] and recurrence of disease (risk ratio=1.20, 95% CI: 1.03-1.40, P=0.02, I(2)=0%). On the basis of our results, in PDAC and CPV, ENE should be considered mandatorily from the gross sampling and pathology report to the oncologic staging and therapeutic approach.

Liquid Biopsy as Surrogate for Tissue for Molecular Profiling in Pancreatic Cancer: A Meta-Analysis Towards Precision Medicine

Liquid biopsy (LB) is a non-invasive approach representing a promising tool for new precision medicine strategies for cancer treatment. However, a comprehensive analysis of its reliability for pancreatic cancer (PC) is lacking. To this aim, we performed the first meta-analysis on this topic. We calculated the pooled sensitivity, specificity, positive (LR+) and negative (LR-) likelihood ratio, and diagnostic odds ratio (DOR). A summary receiver operating characteristic curve (SROC) and area under curve (AUC) were used to evaluate the overall accuracy. We finally assessed the concordance rate of all mutations detected by multi-genes panels. Fourteen eligible studies involving 369 patients were included. The overall pooled sensitivity and specificity were 0.70 and 0.86, respectively. The LR+ was 3.85, the LR- was 0.34 and DOR was 15.84. The SROC curve with an AUC of 0.88 indicated a relatively high accuracy of LB for molecular characterization of PC. The concordance rate of all mutations detected by multi-genes panels was 31.9%. LB can serve as surrogate for tissue in the molecular profiling of PC, because of its relatively high sensitivity, specificity and accuracy. It represents a unique opportunity to be further explored towards its introduction in clinical practice and for developing new precision medicine approaches against PC.

Extranodal extension of lymph node metastasis is a marker of poor prognosis in oesophageal cancer: a systematic review with meta-analysis

The extranodal extension (ENE) of nodal metastasis is the extension of neoplastic cells through the nodal capsule into the perinodal adipose tissue. This histological feature has recently been indicated as an important prognostic factor in different types of malignancies; in this manuscript, we aim at defining its role in the prognosis of oesophageal cancer with the tool of meta-analysis. Two independent authors searched SCOPUS and PubMed until 31 August 2015 without language restrictions. The studies with available data about prognostic parameters in subjects with oesophageal cancer, comparing patients with the presence of ENE (ENE+) versus only intranodal extension (ENE-), were considered as eligible. Data were summarised using risk ratios (RRs) for number of deaths/recurrences and HRs together with 95% CIs for time-dependent risk related to ENE+, adjusted for potential confounders. Fourteen studies were selected; they followed-up 1437 patients with oesophageal cancer for a median follow-up of 39.4 months. The presence of ENE was associated with a significantly increased risk of all-cause mortality (RR=1.33; 95% CI 1.18 to 1.50, p<0.0001, I2=49%; HR=2.72, 95% CI 2.03 to 3.64, p<0.0001, I2=0%), cancer-specific mortality (RR=1.35; 95% CI 1.14 to 1.59, p=0.001, I2=57%; HR=1.97, 95% CI 1.41 to 2.75, p<0.0001, I2=41%) and of risk of recurrence (RR=1.50, 95% CI 1.20 to 1.88, p<0.0001, I2=9%; HR=2.27, 95% CI 1.72 to 2.90, p<0.0001, I2=0%). On the basis of these results, in oesophageal cancer, ENE should be considered from the gross sampling to the pathology report, and in future oncological staging system.

Extranodal extension of nodal metastases is a poor prognostic moderator in non-small cell lung cancer: a meta-analysis

Extranodal extension (ENE) of nodal metastasis is defined as the extension of metastatic cells through the nodal capsule into the perinodal tissue. This morphological parameter, recently proposed as an important prognostic factor in different types of malignancy, has not been included in the TNM staging system for non-small cell lung cancer (NSCLC). In this systematic review with meta-analysis, we weighted the prognostic role of ENE in patients with lymph node-positive NSCLC. Two independent authors searched SCOPUS and PubMed through 28 February 2017. Prospective and retrospective studies on NSCLC, comparing patients with presence of ENE (ENE+) ENE+) vs. only intranodal extension (ENE-) and including data regarding prognosis, were considered as eligible. Data were summarized using risk ratios (RR) for the number of deaths/recurrences, and hazard ratios (HR) with 95% confidence intervals (CI) for time-dependent risk related to ENE+, adjusted for potential confounders. We identified 13 studies, including 1709 patients (573 ENE+ and 1136 ENE-) with a median follow-up of 60 months. ENE was associated with a significantly increased risk of mortality of all causes (RR = 1.39, 95% CI: 1.18-1.65, P < 0.0001, I2 = 70%; HR = 1.30, 95% CI: 1.01-1.67, P = 0.04, I2 = 0%) and of disease recurrence (RR = 1.32, 95% CI: 1.04-1.68, P = 0.02, I2 = 42%; HR = 1.93, 95% CI: 1.53-2.44, P < 0.0001, I2 = 0%). We conclude that in NSCLC, requirements for assessment of ENE should be included in gross sampling and ENE status should be included in the pathology report. Inclusion of ENE status in oncology staging systems will allow further assessment of its role as prognostic parameter.

Extranodal extension of lymph node metastasis influences recurrence in prostate cancer: a systematic review and meta-analysis

The extranodal extension (ENE) of nodal metastasis involves the extension of neoplastic cells through the lymph node capsule into the perinodal adipose tissue. This morphological feature has recently been indicated as an important prognostic factor in various cancer types, but its role in prostate cancer is still unclear. We aimed to clarify it, performing the first meta-analysis on this issue, comparing prognostic parameters in surgically treated, node-positive prostate cancer patients with (ENE+) vs. without (ENE-) ENE. Data were summarized using risk ratios (RRs) for number of deaths/recurrences and hazard ratios (HRs), with 95% confidence intervals (CI), for the time-dependent risk related to ENE positivity. Six studies followed-up 1,113 patients with N1 prostate cancer (658 ENE+ vs. 455 ENE-) for a median of 83 months. The presence of ENE was associated with a significantly higher risk of biochemical recurrence (RR = 1.15; 95%CI: 1.03-1.28; I2 = 0%; HR = 1.40, 95%CI: 1.12-1.74; I2 = 0%) and "global" (biochemical recurrence and distant metastasis) recurrence (RR = 1.15; 95%CI: 1.04-1.28; I2 = 0%; HR = 1.41, 95%CI: 1.14-1.74; I2 = 0%). ENE emerged as a potential prognostic moderator, earmarking a subgroup of patients at higher risk of recurrence. It may be considered for the prognostic stratification of metastatic patients. New possible therapeutic approaches may explore more in depth this prognostic parameter.

PBRM1 loss is a late event during the development of cholangiocarcinoma

AIMS

Somatic mutations in genes encoding chromatin remodellers have been reported recently in several cancer types, including approximately half of cholangiocarcinomas. One of the most commonly mutated chromatin remodellers in cholangiocarcinoma is the Polybromo-1 (PBRM1) gene located on chromosome 3p21, which encodes a subunit of the SWI/SNF complex. The aim of this study was to determine the timing of PBRM1 mutations in biliary carcinogenesis.

METHODS AND RESULTS

In order to accomplish this goal, we used immunohistochemistry to assess PBRM1 protein expression in a series of precursor lesions and invasive biliary carcinomas. Previous studies have correlated loss of protein expression on immunohistochemistry with inactivating mutations in this tumour suppressor gene. We found that PBRM1 loss occurred in approximately 26% of invasive cancers, but PBRM1 expression was retained in all biliary intra-epithelial neoplasia (BilIN) specimens, including 25 intrahepatic BilINs and 19 gallbladder BilINs.

CONCLUSIONS

These findings indicate that PBRM1 mutation (and resultant loss of expression) is a late event during biliary carcinogenesis. In addition, we confirm a lack of prognostic significance of PBRM1 status in invasive intrahepatic cholangiocarcinoma. This study provides important insights into the basic mechanisms of chromatin remodelling genes in carcinogenesis.

CD71 in Gestational Pathology: A Versatile Immunohistochemical Marker With New Possible Applications

Transferrin receptor/CD71 is a membrane protein expressed on nucleated red blood cells (NRBCs) and trophoblasts. Here, we propose the first study to evaluate the usefulness of CD71 immunolabeling in the main fields of gestational pathology. To this aim, formalin-fixed, paraffin-embedded samples of 45 orthotopic (23 spontaneous abortive and 22 molar pregnancies) and 11 ectopic pregnancies were immunostained for CD71. NRBCs were morphologically evident in 23 cases: 12/23 abortive, 4/11 ectopic, and 7/10 partial molar pregnancies. CD71 immunolabeling detected NRBCs in all 23 previous cases and in 8 new cases: 2 partial moles and 6 spontaneous abortive pregnancies. No NRBCs were detected in complete moles by means of either morphology or immunohistochemistry (IHC). In 4 cases with extensive necrotic changes, CD71 marked NRBCs and a few ghost villi, which were not certainly identifiable with standard histological evaluation. Furthermore, there was an inversely proportional relationship between total percentage of CD71-positive NRBCs and gestational age (R=0.69; P<0.0001). We conclude that CD71 is a robust IHC marker for the detection of NRBCs and chorionic villi, especially in the presence of necrosis. The demonstration of NRBCs can be important in molar pathology, helping to exclude a complete mole. The application of CD71 could improve the diagnosis of this pathology in selected cases in which diffuse necrotic or hemorrhagic aspects may hinder the interpretation of the conventional approach with histology, IHC for p57, and ploidy analysis. Finally, the inverse correlation between the total percentage of CD71-positive NRBCs and gestational age suggests that this analysis may help in pregnancy dating.

Specific expression patterns of epithelial to mesenchymal transition factors in gestational molar disease

INTRODUCTION

The epithelial to mesenchymal transition, a well-known and re-emerging model in pathology, has not been completely investigated in the field of gestational pathology. This study aims at improving the comprehension of this process in molar disease, even looking for new possible immunohistochemical markers.

MATERIALS AND METHODS

We have analysed the immunohistochemical expression of Twist1 and Snai2, two of the most important transcription factors involved in epithelial to mesenchymal transition, in formalin-fixed paraffin-embedded samples of 23 spontaneous abortive pregnancies, 22 molar pregnancies (10 partial and 12 complete) and 7 term placentas.

RESULTS

Twist1 and Snai2 were highly expressed in stromal villi cells of molar disease. Particularly, Twist1 was highly expressed in complete moles compared to both abortive pregnancies (p < 0.001) and partial moles (p < 0.05). Also Snai2 was more expressed by complete moles, differentiating them from non-molar abortions (p < 0.05).

DISCUSSION

On the basis of the known cadherins and claudins expression in these pathologies, our new findings reinforce the hypothesis of the involvement of epithelial to mesenchymal transition in early molar pregnancies and above all in complete moles. Furthermore, we highlighted that in molar disease not only the trophoblast, but even the villi stromal cells, are involved. Thanks to their specificity, furthermore, these Twist1 and Snai2 could be used as additional immunohistochemical tool in the diagnosis of complete molar disease, with Twist1 as the first choice.

Pancreatic cancer arising in the remnant pancreas is not always a relapse of the preceding primary

This study aimed to understand the biology of pancreatic ductal adenocarcinoma that arises in the remnant pancreas after surgical resection of a primary pancreatic ductal adenocarcinoma, using integrated histological and molecular analysis. Patients who underwent a completion pancreatectomy for local recurrence following resection of a primary pancreatic ductal adenocarcinoma were studied with histological analysis and next-generation sequencing of the primary and the recurrent cancer. Of six patients that met the inclusion criteria, three cases were classified as "true" recurrences, i.e., the primary and the cancer in the remnant pancreas shared both morphological features and molecular alterations. Two cases were identified as having independent cancers that exhibited different histological and molecular profiles. In the remaining case, the relationship could not be determined. Pancreatic ductal adenocarcinoma that arises in the remnant pancreas can be either a second primary or a "true" relapse of the preceding primary. The differentiation of second primaries from local recurrences may have important implications for patient management.