Association of BCSC-1 with human esophageal squamous cell carcinoma.

Breast cancer suppressor candidate-1 (BCSC-1) is a newly identified candidate tumor suppressor gene. BCSC-1 shows decreased levels in a variety of cancer types. In this study, we investigated the association between BCSC-1 and human esophageal squamous cell carcinoma (ESCC). BCSC-1 expression was detected in ESCC and normal tissues adjacent to tumor tissues by Western blot analysis and real-time PCR  as well as immunohistochemistry of paraffin sections. The relationships between BCSC-1 expression and various clinicopathological characteristics were analyzed. Western blot analysis and real-time PCR showed that levels of BCSC-1 protein and mRNA expression in ESCC significantly decreased compared with those in adjacent normal tissues.  Immunohistochemistry exhibited marked reduction of BCSC-1 in 38 of 105 ESCC specimens. Moreover, downregulation of BCSC-1 was associated with the grade of tumor cellular differentiation (P<0.05). These findings indicate that BCSC-1 downregulation in ESCC is associated with carcinogenesis and may play important roles during the process of ESCC cancer development.