Objective To investigate the expression of PTEN and P 27 proteins in esophageal epitheliosis and carcinogenesis , and the relation to the development of esophageal carcinoma .Methods PTEN and P27 proteins ex-pression in 60 fresh tissue specimens , including esophageal mucosa above the upper surgical margin , carcinoma in si-tu and mucosa adjacent to tumor , were detected using immunohistochemical method .Results The expression of e-sophageal epithelial cells PTEN and P 27 proteins in normal , hyperplastic and malignant gradually decreased , which showed a similar distribution pattern in esophageal carcinogenesis .Conclusion Malignant transformation expression change of PTEN and P 27 proteins and esophageal mucosa are closely related , and the expression of PTEN and P 27 proteins deletion may be a biological marker useful and esophageal cancer early diagnosis index .