Rennstam K, Baldetorp B, Kytölä S, Tanner M, Isola J
Department of Oncology, Jubileum Institute, University Hospital, Lund, Sweden.
Cancer Res. 2001 Feb 1;61(3):1214-9.
Breast carcinoma is thought to arise because of multiple successive changes in the genome of the normal epithelial cells. However, little is known of the order of appearance of different types of genetic aberrations We studied the ERBB2 (Her-2/neu) and CCND1 (cyclin D1) oncogene amplification in flow cytometrically sorted diploid and nondiploid tumor cell populations by fluorescence in situ hybridization (FISH). The purity of the cell sorting was confirmed by static DNA image cytometry. Spectral karyotyping was used to define differences in a genome-wide manner between two distinctly different aneuploid cell clones found in each of two breast cancer cell lines. FISH indicated the presence of gene amplification both in diploid and nondiploid cell clones in 17 of the 21 amplification-containing tumors analyzed. The oncogene copy numbers remained unchanged throughout aneuploidization in 11 of 17 tumors. The remaining six tumors showed an increase in oncogene copy number as well as the number of chromosome 11 or 17 centromeres (the original location of CCNDI and ERBB2, respectively). Breast carcinoma cell lines MDA-157 and MDA-436 showed a significant number of chromosomal rearrangements in the near-diploid clones, which were present in duplicate in the corresponding aneuploid (polyploid) clones. These results indicate that ploidy shift, ie., aneuploidization, in breast cancer is a late genetic event which is preceded by both oncogene amplifications as well as many chromosomal rearrangements.
乳腺癌被认为是由于正常上皮细胞基因组中多次连续变化而产生的。然而，对于不同类型基因畸变出现的顺序知之甚少。我们通过荧光原位杂交（FISH）研究了流式细胞术分选的二倍体和非二倍体肿瘤细胞群体中的ERBB2（Her-2/neu）和CCND1（细胞周期蛋白D1）癌基因扩增情况。通过静态DNA图像细胞术确认了细胞分选的纯度。光谱核型分析用于以全基因组方式定义在两个乳腺癌细胞系中各自发现的两个明显不同的非整倍体细胞克隆之间的差异。FISH表明，在分析的21个含有扩增的肿瘤中的17个中，二倍体和非二倍体细胞克隆中均存在基因扩增。在17个肿瘤中的11个中，癌基因拷贝数在整个非整倍体化过程中保持不变。其余6个肿瘤显示癌基因拷贝数以及11号或17号染色体着丝粒数量增加（分别是CCNDI和ERBB2的原始位置）。乳腺癌细胞系MDA-157和MDA-436在近二倍体克隆中显示出大量染色体重排，这些重排在相应的非整倍体（多倍体）克隆中以重复形式存在。这些结果表明，乳腺癌中的倍性转变，即非整倍体化，是一种晚期遗传事件，在此之前既有癌基因扩增，也有许多染色体重排。
