Microsatellite instability (MSI) results from genetic alterations involving the mismatch repair (MMR) genes MLH1, PSM2, MSH2, and MSH6. MSI has been implicated in both sporadic CRC and Lynch syndrome. The aim of the study was to assess the frequency of alterations in MMR protein expression in both primary colorectal cancer and precursor lesions among Puerto Rican patients.

中文翻译：

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波多黎各人口结肠腺瘤和腺癌中错配修复蛋白缺乏症的频率。

微卫星不稳定性（MSI）是由涉及错配修复（MMR）基因MLH1，PSM2，MSH2和MSH6的遗传变异引起的。MSI与散发性CRC和Lynch综合征有关。这项研究的目的是评估波多黎各人原发性结直肠癌和前体病变中MMR蛋白表达改变的频率。