Thibodeau S N, Bren G, Schaid D
Molecular Genetics Laboratory, Mayo Clinic, Rochester, MN 55905.
Science. 1993 May 7;260(5109):816-9. doi: 10.1126/science.8484122.
Colorectal tumor DNA was examined for somatic instability at (CA)n repeats on human chromosomes 5q, 15q, 17p, and 18q. Differences between tumor and normal DNA were detected in 25 of the 90 (28 percent) tumors examined. This instability appeared as either a substantial change in repeat length (often heterogeneous in nature) or a minor change (typically two base pairs). Microsatellite instability was significantly correlated with the tumor's location in the proximal colon (P = 0.003), with increased patient survival (P = 0.02), and, inversely, with loss of heterozygosity for chromosomes 5q, 17p, and 18q. These data suggest that some colorectal cancers may arise through a mechanism that does not necessarily involve loss of heterozygosity.
对结直肠肿瘤DNA进行检测，以观察人类染色体5q、15q、17p和18q上（CA）n重复序列的体细胞不稳定性。在检测的90个肿瘤中有25个（28%）检测到肿瘤DNA与正常DNA存在差异。这种不稳定性表现为重复序列长度的显著变化（通常性质上是异质性的）或微小变化（通常为两个碱基对）。微卫星不稳定性与肿瘤在近端结肠的位置显著相关（P = 0.003），与患者生存率增加相关（P = 0.02），相反，与染色体5q、17p和18q的杂合性缺失相关。这些数据表明，一些结直肠癌可能通过一种不一定涉及杂合性缺失的机制发生。
