[A negative correlation between Drosha expression and gastric adenocarcinoma malignancy and invasion].

Objective: To investigate the role of Drosha expression in the progression of gastric adenocarcinoma and its impact on the invasive ability of SGC-7901 human gastric cancer cells.

Methods: Drosha expression was detected in 889 gastric carcinoma samples on tissue microarrays by immunohistochemistry staining and quantified by Image-Pro Plus software. Statistical analysis was used to evaluate the correlations between Drosha expression and the clinicopathological characteristics of the 889 tumor cases or the outcomes of 309 gastric adenocarcinoma patients. Drosha was knocked down in SGC-7901 cells by small interfering RNA (siRNA), and cell invasive ability was assessed by Transwell(TM) assay.

Results: Drosha expression was the highest in the well differentiated gastric adenocarcinoma (median absorbance, 0.4195), and the lowest in the poorly differentiated samples. Drosha expression was significantly related to Laren classification, tumor size, tumor invasion depth, lymph node metastasis, tumor pathological grade and stage. Patients in Drosha positive group had a higher survival rate than those in Drosha negative group. Silencing Drosha in SGC-7901 cells resulted in an enhanced cell invasion.

Conclusion: Drosha expression was reduced gradually with the degrading histological differentiation of gastric adenocarcinoma, and the knock-down of Drosha expression could promote gastric adenocarcinoma cell invasion.