Background & objective: Previously, we identified frequent loss of heterozygosity (LOH) at D7S486 of chromosome 7q31 in gastric carcinoma. The TESTIN (TES) gene is a candidate tumor suppressor gene at 7q31.2. This study aimed to investigate the expression of TES in gastric carcinomas, and explore its correlations to clinicopathologic features and prognosis of gastric cancer.
Methods: Semi-quantitative reverse transcription-polymerase chain reaction (RT-PCR) and immunohistochemistry were used to investigate the expression of TES in 140 specimens of primary gastric carcinomas and corresponding adjacent normal tissues; Western blot was performed to evaluate the expression of TES protein in 50 specimens of gastric carcinomas and adjacent normal tissues. The correlations of TES to clinicopathologic features and prognosis of gastric carcinoma were analyzed.
Results: The mRNA level of TES was down-regulated in 96 (68.6%) of the 140 carcinomas as compared with that in matched normal tissues. The positive rate of TES protein was significantly lower in gastric cancer than in normal tissues (22.9% vs. 85.7%, P<0.001). The protein level of TES was down-regulated in 36 (72.0%) of 50 carcinomas as compared with corresponding normal tissues. TES expression was positively correlated with the differentiation of gastric carcinoma (r=0.178, P=0.035). The median survival was significantly shorter in TES-negative patients than in TES-positive patients (P=0.035).
Conclusions: The expression level of TES is significantly down-regulated in primary gastric cancer. TES may be a valuable marker for assessing the prognosis of gastric carcinoma.