Cytoplasmic MTAP expression loss detected by immunohistochemistry correlates with 9p21 homozygous deletion detected by FISH in pleural effusion cytology of mesothelioma.

Histopathology 2019 April 8 [Link]

Hamasaki M, Kinoshita Y, Yoshimura M, Matsumoto S, Kamei T, Hiroshima K, Sato A, Tsujimura T, Kawahara K, Nabeshima K

Abstract

Malignant pleural mesothelioma (MPM) is an aggressive neoplasm with poor prognosis. Diagnosis includes verification of mesothelial origin and discrimination of MPM from reactive mesothelial hyperplasia (RMH) or reactive mesothelial cells (RMC). This can be challenging. Two new markers are available: (1) homozygous deletion (HD) of cyclin-dependent kinase inhibitor 2A (CDKN2A), located at the 9p21 locus, detected by fluorescent in situ hybridization (FISH) and (2) expression loss of BRCA-associated protein 1 (BAP1) protein detected by immunohistochemistry (IHC).