BRG1, INI1, and ARID1B Deficiency in Endometrial Carcinoma: A Clinicopathologic and Immunohistochemical Analysis of a Large Series From a Single Institution

This study immunohistochemically examined the expression status of BRG1, INI1, and ARID1B using 570 archived cases of endometrial carcinoma and carcinosarcoma resected at a single institution. We identified 1 BRG1-deficient undifferentiated carcinoma, 8 BRG1/INI1/ARID1B–deficient DC, and 3 BRG1-deficient clear-cell carcinomas. None of the cases of endometrioid and serous carcinomas or carcinosarcoma showed deficiencies of these subunits. We then compared 8 BRG1/INI1/ARID1B–deficient DC with 6 BRG1/INI1/ARID1B–intact DC and 28 carcinosarcomas, the latter of which was often confused with DC. Histologically, BRG1/INI1/ARID1B–intact and BRG1/INI1/ARID1B–deficient DC shared a monotonous solid appearance with rhabdoid and epithelioid cells and a myxoid stroma; however, abrupt keratinization and cell spindling was absent in BRG1/INI1/ARID1B–deficient tumors. The median overall survival of patients with BRG1/INI1/ARID1B–deficient DC was 3.8 months, which was worse than those with BRG1/INI1/ARID1B–intact DC (P=0.008) and with carcinosarcoma (P=0.004). BRG1/INI1/ARID1B–deficient DC may be a separate entity with an aggressive behavior to be distinguished from BRG1/INI1/ARID1B–intact DC and carcinosarcoma. Regarding clear-cell carcinoma (n=12), BRG1 deficiency appeared to be mutually exclusive with abnormal ARID1A, BRM, and p53 expression. Further studies are needed to clarify whether BRG1 deficiency plays a role in the pathogenesis of clear-cell carcinoma.
Source: The American Journal of Surgical Pathology - Category: Pathology Tags: Original Articles Source Type: research