A variant of estrogen receptor-alpha, ER-alpha36 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-alpha36, 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-alpha36. ER-alpha36 localization in gastric cancer cells was determined with an immunofluorenscence assay. Both mRNA and protein of ER-alpha36 were detected in all established gastric cancer cell lines examined. Higher levels of ER-alpha36 mRNA were expressed in 17 of 22 (77.27%) tumor specimens examined compared to the paired normal tissues (p<0.05). ER-alpha36 protein was expressed mainly on the plasma membrane and in the cytoplasm of the established gastric cancer cells. ER-alpha36 expression is highly correlated with lymph node metastasis in human gastric cancer (P<0.05). The estrogen receptor variant ER-alpha36 is highly expressed in human gastric cancer. ER-alpha36 expression may be used as a predictive marker for lymph node metastasis of gastric cancer.