Overexpression of c-myc messenger RNA in primary and metastatic lesions of carcinoma of the stomach.

Abstract

Although c-myc expression in carcinoma of the stomach has been reported to be involved in progression of the disease, little is known about the mechanism or significance of its expression. We measured c-myc messenger RNA (mRNA) levels by Northern blot hybridization in 51 primary gastric carcinoma lesions and 15 metastatic lesions accompanied by normal mucosal tissues from the same patients. The extent of c-myc mRNA expression in malignant lesions was determined and compared with that in normal mucosal tissues. The clinical and pathologic significance of c-myc mRNA expression was investigated. In 35 (68.6 percent) of 51 primary gastric carcinomas c-myc mRNA was overexpressed. Expression was found to be more frequent and stronger in early lesions than in advanced lesions (90 percent, 6.15-fold compared with 54.8 percent, 2.42-fold, p < 0.05). However, c-myc mRNA expression in the primary lesions showed little influence on either the histologic features or the disease progression. C-myc mRNA levels were higher in every metastatic lesion than in the primary lesions (9.89-fold compared with 3.04-fold, p < 0.05). These observations suggest that c-myc mRNA overexpression may play a role in the early development of primary lesions as well as in the formation of metastatic lesions of carcinomas of the stomach.