Cell polarity protein CRB3 is an independent favorable prognostic factor for clear cell renal cell carcinoma

Abstract

Epithelial cells possess apical-basal polarity and loss of epithelial cell polarity contributes to tumorigenesis and cancer progression. The Crumbs (CR B) polarity protein plays a crucial role in epithelial polarity maintenance, apical membrane formation, and tissue morphogenesis. Although evidence is increasing on involvement of deregulated polarity proteins in cancers, little is currently known about the roles of the CR B (Drosophila), especially the roles of CR B3, a homolog of the CR B, in clear cell renal cell carcinoma (ccRCC ). Studies have shown that CR B3 may act as a tumor suppressor in non-human mammalian cells; the study here was aimed to examine the expression status of CR B3 in ccRCC and the relationships between CR B3 expression and clinicopathologic parameters of ccRCC patients. Our results showed that CR B3 was weakly expressed in ccRCC tissues, but strongly expressed in adjacent normal kidney tissues. Patients with loss of CRB3 expression showed a significantly shorter overall survival (OS) than patients with positive CR B3 expression. Our results suggested that CR B3 may be an independent favorable prognostic factor for patients with ccRCC. We also found that overexpression of CR B3 restrained invasion and migration of 786-O cells and loss of CR B3 expression promoted invasion and migration of human embryonic kidney 293T (HEK 293T) cells. This finding may explain why the negative CR B3 expression was associated with poor prognosis in human ccRCC. Altogether, our data demonstrated that CR B3 may be used as a new independent favorable prognostic factor for human ccRCC.