Rochlitz C F, Herrmann R, de Kant E
Department Innere Medizin, Kantonsspital Basel, Schweiz.
Oncology. 1996 Nov-Dec;53(6):448-54. doi: 10.1159/000227619.
Overexpression and amplification of the c-myc oncogene occur in approximately 70 and 10% of human primary colorectal carcinomas, respectively, indicating the importance of this gene in colorectal tumorigenesis. Little, however, is known about the involvement of c-myc in the progression of colorectal cancer. We therefore determined c-myc gene expression and amplification in a group of primary tumors and metastases from patients with colorectal cancer using quantitative PCR-based tests. While the percentage of metastases overexpressing c-myc (13/26 = 50%) was in the same range as reported for primary tumors by others, gene amplification of c-myc was significantly (p = 0.001) more frequent in metastases (16/27 = 59%) compared to primary tumors (1/23 = 4%) in our series. Interestingly, in 23 metastases where both expression and amplification of c-myc could be determined, there was no correlation between gene copy number and expression level (p = 0.18; r = 0.19). We conclude that amplification but not overexpression of c-myc is related to metastatic progression of colorectal cancer and that overexpression of c-myc is driven by mechanisms other than the number of c-myc copies in the tumors studied.
c-myc癌基因的过表达和扩增分别出现在约70%和10%的人类原发性结直肠癌中，这表明该基因在结直肠癌发生过程中具有重要作用。然而，关于c-myc在结直肠癌进展中的作用，人们了解甚少。因此，我们使用基于定量PCR的检测方法，测定了一组结直肠癌患者原发性肿瘤和转移灶中的c-myc基因表达和扩增情况。虽然过表达c-myc的转移灶百分比（13/26 = 50%）与其他人报道的原发性肿瘤处于相同范围，但在我们的研究系列中，与原发性肿瘤（1/23 = 4%）相比，c-myc基因扩增在转移灶中显著更频繁（16/27 = 59%，p = 0.001）。有趣的是，在23个既能测定c-myc表达又能测定其扩增的转移灶中，基因拷贝数与表达水平之间没有相关性（p = 0.18；r = 0.19）。我们得出结论，c-myc的扩增而非过表达与结直肠癌的转移进展相关，并且在所研究的肿瘤中，c-myc的过表达是由c-myc拷贝数以外的机制驱动的。
