Estrogen Receptor beta Variants mRNA Expressions in Gastric Cancer tissues and Association with Clinicopathologic Parameters

Backgrounds/Aims: The aim of this study is to examine the expression of estrogen receptor beta-1, 2,5 in gastric cancer tissues and evaluate their correlation with clinicopathological features. Methodology: Real-time quantitative PCR assay was applied to detect the expression of estrogen receptor beta-1, 2, 5 mRNAs in 44 gastric cancer tissues and their paired normal tissues and correlate their mRNA levels with the clinicopathological properties of the tumors. 2(Delta CT) method was used to obtain the relative quantity of target mRNA expression. Results: In almost all patients, estrogen receptor beta-1, 2, 5 mRNAs were expressed in gastric cancers and their matched normal tissues; however estrogen receptor beta-5 mRNA was not found in 8 normal gastric tissues. Estrogen receptor beta-5 had a much higher expression than estrogen receptor beta-1, 2 in gastric cancer tissues. Higher estrogen receptor beta-5 mRNA level was observed in gastric cancers than matched normal tissues (p=0.001) and its increased expression was correlated with pTNM stage of the tumor (p=0.032) and the lymph node metastasis (p=0.026). Decreased mRNA level of estrogen receptor beta-1 was observed in gastric cancers compared to their matched normal tissues (p=0.008). Estrogen receptor beta-1, 2 were not correlated with lymph node metastasis, gender, age, tumor size, tumor grade and pTNM stage (p>0.05). Conclusions: This is the first study investigating the clinicopathologic role of estrogen receptor beta variants in gastric cancer. Our study shows that estrogen receptor beta-5 is the most important factor for gastric cancer development and progression among the three estrogen receptor beta variants.