O'Shea A M, Cleary S P, Croitoru M A, Kim H, Berk T, Monga N, Riddell R H, Pollett A, Gallinger S
Department of Pathology and Laboratory Medicine, Mount Sinai Hospital, Toronto, Ontario, Canada.
Histopathology. 2008 Aug;53(2):184-94. doi: 10.1111/j.1365-2559.2008.03071.x. Epub 2008 Jun 28.
MYH is a DNA glycosylase in the base excision repair pathway. Germ-line biallelic mutations in the MYH gene are associated with the development of multiple colorectal adenomas and colorectal carcinoma (CRC). A slightly increased risk of CRC is suggested in monoallelic MYH mutation carriers. The aim was to characterize the histopathological features of carcinomas from biallelics and monoallelics.
Clinicopathological features of 57 colorectal carcinomas from 50 patients identified in familial CRC registries were recorded. These included 16 cancers from 14 MYH biallelics; 25 cancers from 22 MYH monoallelics; and 16 cancers from 14 controls. Carcinomas in biallelics demonstrated tubular, papillary or cribriform patterns as the predominant histological subtype, and main histological groups differed according to mutation status (P = 0.0053). All biallelic cancers were low grade, with high-grade tumours more common in monoallelics and controls (P = 0.002). Synchronous polyps were observed in 75% of biallelics, 33% of monoallelics and 43% of controls (P = 0.035). Serrated carcinoma was the predominant type in 12% (3/25) of the monoallelics but in none of the biallelics or controls. MYH immunohistochemistry failed to distinguish between groups.
Neither pathological features nor immunohistochemistry could predict the MYH mutation status of CRCs in this study.
MYH是碱基切除修复途径中的一种DNA糖基化酶。MYH基因的种系双等位基因突变与多发性结直肠腺瘤和结直肠癌（CRC）的发生有关。单等位基因MYH突变携带者患CRC的风险略有增加。目的是描述双等位基因和单等位基因突变携带者所患癌的组织病理学特征。
记录了在家族性CRC登记处确定的50例患者中57例结直肠癌的临床病理特征。其中包括14例MYH双等位基因突变携带者的16例癌症；22例MYH单等位基因突变携带者的25例癌症；以及14例对照者的16例癌症。双等位基因突变携带者的癌以管状、乳头状或筛状模式为主要组织学亚型，主要组织学类型因突变状态而异（P = 0.0053）。所有双等位基因突变携带者的癌症均为低级别，高级别肿瘤在单等位基因突变携带者和对照者中更常见（P = 0.002）。75%的双等位基因突变携带者、33%的单等位基因突变携带者和43%的对照者观察到同步息肉（P = 0.035）。锯齿状癌在12%（3/25）的单等位基因突变携带者中为主要类型，但在双等位基因突变携带者或对照者中均未出现。MYH免疫组化未能区分各组。
在本研究中，病理特征和免疫组化均无法预测CRC的MYH突变状态。
