P53 MUTATION AND PROTEIN OVEREXPRESSION IN THE EARLY STAGES OF ESOPHAGEAL TUMORIGENESIS UTILIZING ENDOSCOPICALLY OBTAINED BIOPSY SPECIMENS

It is unclear whether p53 abnormality in the early esophageal tumorige nesis causes clonal expansion with tumor growth. In this study, we ana lyzed p53 abnormalities by PCR-SSCP and immunohistochemistry in 86 eso phageal endoscopic biopsy specimens. Eleven of 27 specimens (39%) of m ild dysplasias showed p53 mutations. Six moderate or mild dysplasias w ere followed by endoscopy (average 73 weeks) and continually exhibited the same p53 mutation, but none of them showed apparent tumor growth and subepithelial epithelial invasion. These results suggest that p53 mutations occur very early in the esophageal tumorigenesis and contrib ute to cell proliferation, but cannot be related with malignant phenot ype directly.