Results of epidemiological studies have shown that
nitrosamine-induced carcinogensis is involved in
esophageal cancer in China. In order to demonstrate the mechanism at molecular level, Multiple tumor suppressor genes Rb, p53, APC and MCC in human fetus esophageal epithelium treated with
NMBzA (in vitro) for 24 hours or three weeks and esophageal
carcinoma induced by
NMBzA were analyzed with PCR amplification and direct sequencing. In PCR amplification analysis. Rb, p53, APC and MCC deletions in esophageal
carcinoma of human fetus induced by
NMBzA were found, but no deletions of these genes was demonstrated in
NMBzA-treated human fetal esophageal epithelium. PCR direct sequencing analysis revealed mutation of p53, Rb and MCC genes in human fetal esophageal epithelium treated with
NMBzA for three weeks. The results first confirmed (in vitro) that
nitrosamine can cause mutations and deletions of multiple tumor suppressor genes in human esophageal epithelium. The mutations of tumor suppressor genes in
nitrosamine-induced esophageal
carcinoma may occur in the early stage, while deletions in late stage of
carcinogenesis.