Immunohistochemical evaluation of two antibodies against PD-L1 and prognostic significance of PD-L1 expression in epithelioid peritoneal malignant mesothelioma: A RENAPE study.

Epithelioid peritoneal malignant mesothelioma (EPMM) is the most common subtype of this aggressive tumor. We compared two antibodies against PD-L1, a recent theranostic biomarker, and evaluated the prognostic value of PD-L1 expression by mesothelial and immune cells in EPMM. Immunohistochemistry was performed on 45 EPMM. Clinical and pathological data were extracted from the RENAPE database. Using E1L3N and SP142 clones, inter-observer agreement, PD-L1 expression by mesothelial and immune cells and inter-antibody agreement were evaluated. The prognostic relevance of PD-L1 expression was evaluated in 39 EPMM by univariate and multivariate analysis of overall survival (OS) and progression-free survival (PFS). Inter-observer agreement on E1L3N immunostaining was moderate for mesothelial and immune cells, and fair for mesothelial and poor for immune cells using SP142. Using E1L3N, 31.1% of mesothelial and 15.6% of immune cells expressed PD-L1, and 22.2% of mesothelial and 26.7% of immune cells using SP142. Inter-antibody agreement was moderate. In most positive cases, 1-5% of tumor cells were positive. Using E1L3N, PD-L1 expression by lymphocytes was associated with better OS and PFS by both univariate and multivariate analysis. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy predicted better prognosis than other treatments. Solid subtype was an independent prognostic factor for worse OS. E1L3N appeared easier to use than SP142 to evaluate PD-L1 expression. A minority of EPMM expressed PD-L1, and only a few cells were positive. PD-L1 expression by immune cells evaluated with E1L3N was an independent prognostic factor in EPMM

Mucinous Neoplasms Of The Appendix And Peritoneum: Virtual Microscopy For Histomorphologic Assessment And Interobserver Diagnostic Reproducibility : SY02.06 | Telepathology

INTRODUCTION / BACKGROUND: Among gastrointestinal (GI) tumours, pseudomyxoma peritonei (PMP) from appendiceal origin has unique clinical and morphologic features. Due to the relative paucity of patients and the absence of therapeutic consensus, evaluation and refinement of the morphologic criteria used for assessment of the disease are still difficult. As a result, a uniformly accepted classification is still lacking. In collaboration with NJ Carr, who initiated the conference consensus process, in Basingstoke, and on behalf of the French group RENA-PATH, 11 experienced GI pathologists agreed to participate to a virtual workshop, in order to assess inter-observer variability in PMP diagnosis and staging. AIMS: The goal of the study was to evaluate, for appendiceal and peritoneal mucinous neoplasms, the degree of concordance in the identification of diagnostic histological criteria by experienced pathologists, and to assess the degree of inter-individual variation in the application of WHO classification (2010) and TNM staging system (7th edition). METHODS: A single section stained with hematoxylin and eosin from 9 resected cases of mucinous neoplasms was selected by members of RENA-PATH. All digitalized at a maximum resolution (X40) using an HAMMAMATSU scanner system, to ensure that all participants evaluate exactly the same tumour areas; 1 to 16 questions were prepared for each case. On Teleslide web platform, interactive services provided by TRIBVN. All submitted cases were then reviewed by a panel of 11 pathologists with specific expertise and interest in PMP. Data were analyzed using SAS program. RESULTS: Whole slide set evaluated by all participants; no abstention or “unknown diagnosis” for any submitted case. Agreement for classification, WHO 2010: -Appendiceal mucinous neoplasms: LAMN 83 %; mucinous adenocarcinoma 92%. -Peritonei mucinous carcinoma: Low grade 91.7%; high grade 91.7%. -Disagreement on the concept of High Grade AMN defined by low power architecture of LAMN + high grade cytology. -Agreement for using pTNM classification (82%) in PMP. -Pushing Invasion (PI) and dissection by acellular mucin (DAM) in appendix wall are not reproducible criteria and need to be better defined. -Criteria need to be redefined to use HAMN according to a majority of participants. -The identification of signet ring cells is not reproducible; the lesion needs to be better defined. -Invasion of organs and pattern of invasion (broatfront invasion / classic by irregular glands or single cells with desmoplasia) are not reproducible criteria. -Improvement in staging assessment is neede

A new internet tool to report peritoneal malignancy extent. PeRitOneal MalIgnancy Stage Evaluation (PROMISE) application

International audienceBased on the importance of assessing the true extent of peritoneal disease, PeRitOneal MalIgnancy Stage Evaluation (PROMISE) internet application (www.e-promise.org) has been developed to facilitate tabulation and automatically calculate surgically validated peritoneal cancer index (PCI), and other surgically validated scores as Gilly score, simplified peritoneal cancer index (SPCI), Fagotti and Fagotti-modified scores. This application offers computer-assistance to produce simple, quick but precise and standardized pre, intra and postoperative reports of the extent of peritoneal metastases and may help specialized and non-specialized institutions in their current practice but also facilitate research and multicentre studies on peritoneal surface malignancies

Immunohistochemical evaluation of two antibodies against PD-L1 and prognostic significance of PD-L1 expression in epithelioid peritoneal malignant mesothelioma: A RENAPE study

International audienceBACKGROUND:Epithelioid peritoneal malignant mesothelioma (EPMM) is the most common subtype of this aggressive tumor. We compared two antibodies against PD-L1, a recent theranostic biomarker, and evaluated the prognostic value of PD-L1 expression by mesothelial and immune cells in EPMM.METHODS:Immunohistochemistry was performed on 45 EPMM. Clinical and pathological data were extracted from the RENAPE database. Using E1L3N and SP142 clones, inter-observer agreement, PD-L1 expression by mesothelial and immune cells and inter-antibody agreement were evaluated. The prognostic relevance of PD-L1 expression was evaluated in 39 EPMM by univariate and multivariate analysis of overall survival (OS) and progression-free survival (PFS).RESULTS:Inter-observer agreement on E1L3N immunostaining was moderate for mesothelial and immune cells, and fair for mesothelial and poor for immune cells using SP142. Using E1L3N, 31.1% of mesothelial and 15.6% of immune cells expressed PD-L1, and 22.2% of mesothelial and 26.7% of immune cells using SP142. Inter-antibody agreement was moderate. In most positive cases, 1-5% of tumor cells were positive. Using E1L3N, PD-L1 expression by lymphocytes was associated with better OS and PFS by both univariate and multivariate analysis. Cytoreductive surgery with hyperthermic intraperitoneal chemotherapy predicted better prognosis than other treatments. Solid subtype was an independent prognostic factor for worse OS.CONCLUSION:E1L3N appeared easier to use than SP142 to evaluate PD-L1 expression. A minority of EPMM expressed PD-L1, and only a few cells were positive. PD-L1 expression by immune cells evaluated with E1L3N was an independent prognostic factor in EPMM