Department of Surgery, Taipei Veterans General Hospital, National Yang-Ming University, Taiwan.
Int J Colorectal Dis. 2010 Jan;25(1):47-52. doi: 10.1007/s00384-009-0815-y. Epub 2009 Oct 22.
Microsatellite analysis is a screening tool used for the identification of Lynch syndrome. We evaluated the occurrence of high-frequency microsatellite instability (MSI-H) in 160 patients with colorectal cancer < or =60 years old to determine if these individuals should be routinely tested for microsatellite instability.
From January 2004 and December 2006, we tested specimens of colorectal cancer from 160 patients under 60 years of age for microsatellite instability. The relationships between clinicopathological parameters and MSI-H status were analyzed.
MSI-H occurred in 11.3% (18/160) of the tumors assayed, and colorectal tumors with MSI-H status were located predominantly to the right side (56%, P < 0.001) and had a lower pathological stage (72%, P = 0.011). Of the 18 MSI-H tumors, six displayed characteristic MSI histology. Furthermore, of the 18 MSI-H tumors, instability in BAT-26 was 100%, BAT-25 was 94%, D17S250 was 72%, D2S123 was 68%, and D5S346 was 68%. Of the patients with MSI-H tumors, 55.6% were more than 50 years of age, and about 70% of MSI-H tumors did not display characteristic MSI histology. Importantly, up to 40% of the MSI-H patients in this study would have been overlooked using the revised Bethesda guidelines. The revised Bethesda guidelines, broadened to include patients with right-sided colon cancer, could have identified 94% of the MSI-H tumors in this study.
Colorectal cancers with MSI-H were predominantly located on the right side and had an early pathological stage. The results of this study suggest that microsatellite instability test should be used for all patients under 60 years of age with right-sided colon cancer.
微卫星分析是一种用于识别林奇综合征的筛查工具。我们评估了 160 例 < 60 岁结直肠癌患者中高频微卫星不稳定性（MSI-H）的发生情况，以确定这些个体是否应常规进行微卫星不稳定性检测。
从 2004 年 1 月至 2006 年 12 月，我们对 160 例 < 60 岁的结直肠癌患者的标本进行了微卫星不稳定性检测。分析了临床病理参数与 MSI-H 状态之间的关系。
160 例肿瘤中有 11.3%（18 例）发生 MSI-H，MSI-H 状态的结直肠肿瘤主要位于右侧（56%，P < 0.001），且病理分期较低（72%，P = 0.011）。18 例 MSI-H 肿瘤中，6 例表现出特征性 MSI 组织学。此外，在 18 例 MSI-H 肿瘤中，BAT-26 不稳定率为 100%，BAT-25 为 94%，D17S250 为 72%，D2S123 为 68%，D5S346 为 68%。MSI-H 肿瘤患者中，55.6%年龄 > 50 岁，约 70%的 MSI-H 肿瘤未表现出特征性 MSI 组织学。重要的是，使用修订后的贝塞斯达指南，本研究中多达 40%的 MSI-H 患者可能被忽视。修订后的贝塞斯达指南扩大到包括右侧结肠癌患者，本研究中可识别 94%的 MSI-H 肿瘤。
MSI-H 结直肠癌主要位于右侧，且具有早期病理分期。本研究结果表明，所有 60 岁以下右侧结肠癌患者均应进行微卫星不稳定性检测。
