Reduced expression levels of the death-associated protein kinase and E-cadherin are correlated with the development of esophageal squamous cell carcinoma

The aim of this study was to investigate the expression levels of the death-associated protein kinase (DAPK) and E-cadherin in esophageal squamous cell carcinoma (ESCC) and their correlation with clinical and pathological factors. Immunohistochemistry [streptavidin-peroxidase (SP) method], in situ hybridization, immunoblot assays and reverse transcription-PCR (RT-PCR) were used to detect the expression of DAPK and E-cadherin in the carcinomas and the adjacent normal tissues of 76 cases of esophageal squamous carcinomas. The immunoblot assay indicated that the expression levels of DAPK and E-cadherin were decreased significantly in the ESCC tissue (P<0.05) when compared with the adjacent normal tissues. The RT-PCR results showed that the mRNA levels of DAPK and E-cadherin were reduced. The abnormal expression of DAPK was highly correlated with the invasiveness and lymphatic metastasis of the cancer. The abnormal expression of E-cadherin was highly correlated with the differentiation and lymphatic metastasis of the cancer. The decreased expression levels of DAPK and E-cadherin correlated with the development of ESCC. The combined detection of DAPK and E-cadherin proteins may be correlated with the degree of malignancy and metastatic potency of ESCC.