Evaluating Mismatch Repair/Microsatellite Instability Status Using Cytology Effusion Specimens to Determine Eligibility for Immunotherapy.

ABSTRACT:

Context.—

The approval of pembrolizumab for treatment of patients with microsatellite instability-high (MSI-H) or mismatch repair-deficient (dMMR) advanced cancers has led to increased requests for MSI and/or MMR immunoperoxidase (IPOX) testing. Diagnoses for patients with advanced-stage cancer are frequently made from cytology specimens.

Objective.—

To investigate the feasibility of using cell block (CB) preparations of effusions for MMR IPOX evaluation.

Design.—

Surgical pathology cases of colorectal and endometrial carcinomas with known MMR/MSI status and matched effusions with available CBs were identified. Cell block sections were evaluated for adequacy and stained with MMR IPOX (MSH2, MSH6, MLH1, and PMS2). The CBs were reviewed, the number of tumor cells quanti

SUBMITTER: Jacobi EM 

PROVIDER: S-EPMC7529913 | biostudies-literature | 2021 Jan

REPOSITORIES: biostudies-literature