H Li1, S Lu, L Fong. 1. Cancer Institute, Chinese Academy of Medical Science, Peking Union Medical College, Beijing.
Abstract
OBJECTIVE: To elucidate the cause of abnormal Rb expression in esophageal cancer (EC). METHODS: Methylation of Rb gene promoter was examined with restriction endonuclease digestion and PCR amplification. RESULTS: Of the 30 specimens of EC, 10 (33.3%) had Msp I type hypermethylation of the Rb gene promoter while 12 (40.0%) had Hpa II type hypermethylation and one had both type of hypermethylation. In monkey fed with a single dose of NMBzA (30 mg/kg) on day 0, increasing hypermethylation of both types of the Rb gene promoter in esophageal epithelium was found on day 1, 2 and 3 but reduced on day 5. CONCLUSION: These data suggest that abnoromal expression of Rb gene may be related to hypermethylation of its promoter and carcinogen NMBzA can induce such hypermethylation in monkey esophageal epithelium.
OBJECTIVE: To elucidate the cause of abnormal Rb expression in esophageal cancer (EC). METHODS: Methylation of Rb gene promoter was examined with restriction endonuclease digestion and PCR amplification. RESULTS: Of the 30 specimens of EC, 10 (33.3%) had Msp I type hypermethylation of the Rb gene promoter while 12 (40.0%) had Hpa II type hypermethylation and one had both type of hypermethylation. In monkey fed with a single dose of NMBzA (30 mg/kg) on day 0, increasing hypermethylation of both types of the Rb gene promoter in esophageal epithelium was found on day 1, 2 and 3 but reduced on day 5. CONCLUSION: These data suggest that abnoromal expression of Rb gene may be related to hypermethylation of its promoter and carcinogen NMBzA can induce such hypermethylation in monkey esophageal epithelium.