Prognostic significance of c-myc mRNA expression assessed by semi-quantitative RT-PCR in patients with colorectal cancer.

To clarify the prognostic value of the c-myc oncogene mRNA expression levels in human colorectal cancer, samples obtained from 35 surgically resected tissues were examined by the semi-quantitative reverse transcriptase-polymerase chain reaction (RT-PCR). Overexpression of c-myc mRNA was detected in 22 cases (63%). Although there was no correlation between c-myc overexpression and the depth of invasion, lymph node metastasis, or Dukes' stage, the patients with c-myc overexpression had metastatic recurrences significantly more frequently than those without it (29% versus 0%, p<0.05). The disease-free survival rate at 5 years was significantly lower in patients with c-myc overexpression than in those without it (70% versus 100%, p<0.05). These results demonstrate that c-myc mRNA overexpression as assessed by semi-quantitative RT-PCR may be a useful prognostic indicator in patients with colorectal cancer.