Both MLH1 deficiency and BRAFV600E mutation are a unique characteristic of colorectal medullary carcinoma: An observational study.

Autor:	Kaneko M; First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan., Nakashima M; Department of Biochemistry, Hamamatsu University of School of Medicine, Hamamatsu, Japan., Sugiura K; First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan., Ishida N; Department of Endoscopic and Photodynamic Medicine, Hamamatsu University of School of Medicine, Hamamatsu, Japan., Tamura S; First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan., Tani S; First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan., Yamade M; First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan., Hamaya Y; First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan., Osawa S; Department of Endoscopic and Photodynamic Medicine, Hamamatsu University of School of Medicine, Hamamatsu, Japan., Tatsuta K; Department of Surgery, Hamamatsu University of School of Medicine, Hamamatsu, Japan., Kurachi K; Department of Surgery, Hamamatsu University of School of Medicine, Hamamatsu, Japan., Baba S; Department of Diagnostic Pathology, Hamamatsu University School of Medicine, Hamamatsu, Japan., Iwashita Y; Department of Tumor Pathology, Hamamatsu University School of Medicine, Hamamatsu, Japan., Arai T; Department of Pathology, Tokyo Metropolitan Geriatric Hospital and Institute of Gerontology, Tokyo, Japan., Sugimura H; Department of Tumor Pathology, Hamamatsu University School of Medicine, Hamamatsu, Japan., Maekawa M; Department of Laboratory Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan., Sugimoto K; First Department of Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan., Iwaizumi M; Department of Laboratory Medicine, Hamamatsu University School of Medicine, Hamamatsu, Japan.
Jazyk:	angličtina
Zdroj:	Medicine [Medicine (Baltimore)] 2023 Sep 22; Vol. 102 (38), pp. e35022.
DOI:	10.1097/MD.0000000000035022
Abstrakt:	Although immunohistochemistry (IHC) for mismatch repair (MMR) proteins (MMR IHC) is used to identify DNA MMR status, universal screening of all patients with colorectal cancer (CRC) using a combination of both MMR IHC and genetic testing for the BRAFV600E mutation is limited in Japan. This study aimed to better understand the histopathological characteristics of CRCs, which exhibit both deficient mismatch repair (dMMR) and BRAFV600E mutation. MMR IHC of formalin-fixed paraffin-embedded tissues from tumor areas obtained from 651 patients with CRC who underwent surgical resection at Hamamatsu University Hospital (Hamamatsu, Japan) between August 2016 and March 2022 were used to evaluate MMR status, which was determined by staining for the expression of 4 MMR proteins (MLH1, MSH2, PMS2, and MSH6). All dMMR tumors were additionally evaluated for BRAFV600 mutation status via Sanger sequencing. Patient clinical characteristics (age, sex, tumor location, size, and tumor pathology) were then classified using their dMMR and BRAFV600 mutation statuses. Among the 651 patients with CRC, 58 carried tumors with dMMR, of which 52 were deficiency in MLH1 (dMLH1). Interestingly, all 16 medullary carcinomas that were analyzed showed characteristics corresponding to the presence of both dMLH1 and BRAFV600E mutation (P = .01). These results suggest that colorectal medullary carcinomas can be diagnosed based on their unique characteristics of harboring the BRAFV600E mutation and exhibiting dMLH1 expression. Competing Interests: The authors have no conflicts of interest to disclose. (Copyright © 2023 the Author(s). Published by Wolters Kluwer Health, Inc.)
Databáze:	MEDLINE
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