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

BACKGROUND: 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.

[2002 Standards, Options and Recommendations: good practice for the management and shipment of histological and cytopathological cancer specimens]. / Standards, Options et Recommandations 2002 bonnes pratiques de l'acheminement et de la prise en charge initiale d'un prélèvement en anatomie et cytologie pathologiques en cancérologie (rapport intégral).

CONTEXT: The Standards, Options and Recommendations (SOR) collaborative project was initiated in 1993 by the Federation of the French Cancer Centres (FNCLCC), with the 20 French Regional Cancer Centres, several French public university and general hospitals, as well as private clinics and medical speciality societies. Its main objective is the development of serviceable clinical practice guidelines in order to improve the quality of health care and the outcome of cancer patients. The methodology is based on a literature review, followed by critical appraisal by a multidisciplinary group of experts. Draft guidelines are produced, then validated by specialists in cancer care delivery. OBJECTIVES: Produce clinical practice guidelines for the management and shipment of histological and cytopathological cancer specimens using the methodology developed by the Standards, Options and Recommendations project. METHODS: The FNCLCC designated the group of experts. Available data were collected by a search of Medline and lists selected by experts in the group. A first draft of the guidelines was written, then validated by independent reviewers. RESULTS: The main recommendations are: 1/ High-quality transmission of information between professionals is essential to the management of cancer specimens in order to assure high-quality diagnosis and evaluation of prognostic factors; 2/ Written procedures concerning sample shipment, handling, storage, registration, tracking and fixation exist; these procedures, as well as the necessary shipping material, will be sent to all clinical services involved; 3/ When possible, fresh, unfractionated, oriented surgical samples will be submitted to the same histological and cytopathological laboratory; 4/ Samples collected for extemporaneous examination, freezing or cell culture must be shipped immediately under appropriate storage conditions; 5/ Once frozen, samples can be stored in a deep freezer at temperatures of -80 degrees C or below, or kept in liquid nitrogen; 6/ Fixing tissues shortly after sample collection is essential to prevent cell lysis; 7/ Computerised systems will be used to assure correct specimen registration and tracking in histological and cytopathological laboratories.

[Standards, options and recommendations: practice guidelines for difficult diagnosis in surgical pathology or cytopathology in cancer patients]. / Standards, options et recommandations: conduite a tenir devant une lésion de diagnostic anatomo-cyto-pathologique difficile en cancérologie.

CONTEXT: The "Standards, Options and Recommendations" (SOR) project, started in 1993 is a collaboration between the Federation of the French Cancer Centres (FNCLCC), the 20 French Cancer Centres and specialists from French Public Universities, General Hospitals and Private Clinics. The main objective is the development of clinical practice guidelines to improve the quality of health care and outcome for cancer patients. The methodology is based on literature review and critical appraisal by a multidisciplinary group of experts, with feedback from specialists in cancer care delivery. OBJECTIVES: To develop clinical practice guidelines according to the definitions of the Standards, Options and Recommendations project for difficult diagnoses in surgical pathology or cytopathology in cancer patients. METHODS: Data were identified by searching Medline and using the personal reference lists of members of the expert groups. Once the guidelines were defined, the document was submitted for review to 71 independent reviewers. RESULTS: The main recommendations to prevent and reduce the number of difficult diagnoses in surgical pathology or cytopathology are: 1) The development of quality insurance programs with use of written procedures in each pathology laboratory (standard). 2) The knowledge of clinical data in order to explain surgical pathology or cytopathology results (standard). 3) The availability of complementary patient informations (radiologic data . . .) can be useful to explain surgical pathology or cytopathology results (option). The main recommendations to detect lesions associated with difficult diagnosis in surgical pathology or cytopathology are: 1) Tumor types known as potential difficult diagnosis in surgical pathology or cytopathology should be reviewed by a second pathologist. 2) The systematic second reviewing for every case is expensive but has to be done when the difficulty is know (sarcoma, lymphoma . . .) by experienced pathologists. The main recommendations to solve difficult diagnosis in surgical pathology or cytopathology are: 1) Block recuts, use of special techniques (immunocytohistochemistry and molecular biology), additional data from clinicians, second opinion by a local pathologist, or new specimen can be required for establishing the diagnosis (options). 2) Outside second opinion by expert pathologist has to be considered once the other steps did not allow to establish surgical or cytopathology diagnosis (recommendations, expert agreement).