Sugai T, Habano W, Nakamura S, Sato H, Uesugi N, Orii S, Itoh C, Katoh R
Department of First Internal Medicine, School of Medicine, Iwate Medical University, Morioka, Japan.
Hum Pathol. 2000 Aug;31(8):925-30. doi: 10.1053/hupa.2000.9087.
17p, 5q, and 18q allelic losses are involved in the pathogenesis and progression of colorectal carcinoma, and DNA aneuploidy in this type of cancer is thought to result from alterations of these chromosomal loci. However, genetic differences between diploid and aneuploid populations of multiploid carcinoma, defined as the coexistence of diploid and aneuploid populations in the same area, remain unclear. The differences in 17p, 5q, and 18q allelic losses between the diploid and aneuploid populations in 24 sporadic DNA multiploid colorectal carcinomas were analyzed by use of crypt isolation coupled with DNA cytometric sorting and polymerase chain reaction assay. 17p Allelic loss was observed in 7 of 22 diploid populations excluding 1 case of microsatellite instability but was found in 21 of 23 aneuploid populations. Although 5q allelic loss was detected in only 3 of 22 diploid populations, 13 of 22 aneuploid populations had 5q allelic loss. Losses of the 18q allele were frequently found in aneuploid populations (15 of 20), although no 18q allelic loss was detected in corresponding diploid populations. 17p Allelic losses may play an important role in the progression from a diploid status to an aneuploid status in a specific subset of colorectal cancer. However, 18q or 5q allelic losses do not appear to precede nor to facilitate the aneuploid clonal divergence of cancer cells. Multiploidy is a useful model to study genetic alterations between diploid and aneuploid populations.
17号染色体短臂（17p）、5号染色体长臂（5q）和18号染色体长臂（18q）的等位基因缺失与结直肠癌的发病机制及进展有关，并且这种类型癌症中的DNA非整倍体被认为是由这些染色体位点的改变所致。然而，多倍体癌中二倍体和非整倍体群体之间的遗传差异仍不清楚，多倍体癌是指在同一区域中二倍体和非整倍体群体共存的情况。通过隐窝分离结合DNA细胞分选和聚合酶链反应分析，对24例散发性DNA多倍体结直肠癌中二倍体和非整倍体群体之间17p、5q和18q等位基因缺失的差异进行了分析。在22个二倍体群体中的7个中观察到17p等位基因缺失（排除1例微卫星不稳定性病例），但在23个非整倍体群体中的21个中发现了17p等位基因缺失。虽然在22个二倍体群体中仅在3个中检测到5q等位基因缺失，但在22个非整倍体群体中的13个中存在5q等位基因缺失。18q等位基因缺失在非整倍体群体中经常出现（20个中有15个），尽管在相应的二倍体群体中未检测到18q等位基因缺失。17p等位基因缺失可能在结直肠癌特定亚群从二倍体状态向非整倍体状态的进展中起重要作用。然而，18q或5q等位基因缺失似乎既不会先于癌细胞的非整倍体克隆分化，也不会促进其发生。多倍体是研究二倍体和非整倍体群体之间遗传改变的有用模型。
