A variant of estrogen receptor-α, ER-α36 is expressed in human gastric cancer and is highly correlated with lymph node metastasis

Gastric cancer is one of the most common cancers in the world; almost two-thirds of gastric cancer cases and deaths occur in less developed regions. The molecular and cellular events during development of gastric cancer remain unclear. Herein, we examined the expression of ER-alpha 36, an ER-alpha variant, in established gastric cancer cell lines and specimens from 22 gastric cancer patients. RT-PCR, Western blot and immunohistochemistry methods were used to assess expression levels of ER-alpha 36. ER-alpha 36 localization in gastric cancer cells was determined with an immunofluorenscence assay. Both mRNA and protein of ER-alpha 36 were detected in all established gastric cancer cell lines examined. Higher levels of ER-alpha 36 mRNA were expressed in 17 of 22 (77.27%) tumor specimens examined compared to the paired normal tissues (p<0.05). ER-alpha 36 protein was expressed mainly on the plasma membrane and in the cytoplasm of the established gastric cancer cells. ER-alpha 36 expression is highly correlated with lymph node metastasis in human gastric cancer (P<0.05). The estrogen receptor variant ER-alpha 36 is highly expressed in human gastric cancer. ER-alpha 36 expression may be used as a predictive marker for lymph node metastasis of gastric cancer.