Flotillin2 Expression Correlates with HER2 Levels and Poor Prognosis in Gastric Cancer

Objective Flotillin gene is known as a tumor promoter or suppressor, depending on the tumor type or tumor stage. We aimed to investigate the clinical significance of flotillin2 protein expression in gastric cancer. Methods We examined flotillin2 and erbB2 levels in tissue microarray of 282 gastric cancer samples and analyzed the association between flotillin2 levels, clinicopathologic factors and prognosis. The regulation of erbB2 by flotillin2 was examined with flotillin2 siRNA–transfected gastric cancer cells. Results Flotillin2 partially co-localized with erbB2 at the plasma membrane as detected by confocal microscopy, levels of erbB2 were reduced after flotillin knockdown in SGC-7901 cancer cells, and the expression of flotillin2 was positively correlated with that of erbB2. In non-neoplastic gastric mucosa, flotillin2 was not expressed in the epithelial compartment. In gastric cancer, positive staining of flotillin2 was shown in 129 (45.7%) of 282 cases, also, it was significantly associated with a Lauren grade, histologic type, lymphovascular invasion and tumor location. Moreover, survival analysis showed that flotillin2 expression was an independent prognostic factor of poor survival (p<0.001). Conclusions These results indicate that a positive correlation exists between flotillin2 and erbB2 expression levels, flotillin2 maybe involved in the stabilization of erbB2 at the plasma membrane, flotillin2 is significantly correlated with cancer progression and poor prognosis in gastric cancer.