Mutational Analysis of the PTEN Gene and Its Effects in Esophageal Squamous Cell Carcinoma

Esophageal squamous cell carcinoma (ESCC) is one of the most frequently diagnosed cancers in China, but the etiology and mode of carcinogenesis of this disease remain poorly understood. The phosphatase and tensin homolog deleted from chromosome 10 (PTEN) with putative tumor suppressing is frequently mutated in many cancers. The aim of this study was to investigate whether there exists a mutation in the PTEN gene of the ESCC cells, and the effects of the wild type and mutated PTEN genes on the proliferation and apoptosis of the ESCC cells. The wild type and mutated PTEN genes were cloned from human placenta and ESCC cells, respectively, and their effects on the proliferation and apoptosis of the ESCC cells were investigated. Also, the relationship between the PTEN gene status and sensitivity of the EC9706 cells to cisplatin was determined in the xenografts of nude mice. There were mutations in the PTEN gene from ESCC cells. The proliferation of the EC9706 cells was clearly inhibited by the wild type PTEN gene, but not by the mutated PTEN gene in vitro. Furthermore, the wild type PTEN gene inhibited the growth of transplantable tumor, induced cell apoptosis, and improved the sensitivity of the EC9706 cells to cisplatin in vivo. The findings of the present study demonstrate that there are mutations in the PTEN gene of the ESCC cells and that the wild type PTEN gene has important effects on the ESCC cells in vitro and in vivo.