Determining the microsatellite instability (MSI) status of colorectal carcinoma (CRC) and other tumor types has recently increased in importance for patient management and prevention strategies.^1,2 High-level MSI (MSI-H)/deficient mismatch repair (dMMR) (widely used alternative terminologies) has long been known to be a hallmark of Lynch syndrome. The identification of this small subset of patients (approximately 3% of patients with CRC) has major implications for prevention in blood relatives and for avoiding metachronous tumors in patients who have a first Lynch-associated tumor. Preoperative decisions can be made about prophylactic surgery at the initial treatment, including abdominal colectomy and hysterectomy with bilateral salpingo-oophorectomy after childbearing is completed.

确定结直肠癌 (CRC) 和其他肿瘤类型的微卫星不稳定性 (MSI) 状态对于患者管理和预防策略的重要性最近增加。^1,2高水平 MSI (MSI-H)/缺陷错配修复 (dMMR)（广泛使用的替代术语）长期以来一直被认为是 Lynch 综合征的标志^。确定这一小部分患者（约 3% 的 CRC 患者）对于预防血亲和避免患有首发 Lynch 相关肿瘤的患者的异时性肿瘤具有重要意义。可以在初始治疗时就预防性手术做出术前决定，包括在生育完成后进行腹部结肠切除术和双侧输卵管卵巢切除术的子宫切除术。