Studies of loss of heterozygosity(LOH) in Chinese human gastric cancer tissues

Objective: To identify the LOH frequency in Chinese gastric cancer samples and locate lost region of gastric cancer-related tumor suppressor gene.

Methods: Thirty microsatellite markers were used to examine 42 cases of tumor-normal paired gastric cancer tissues for LOH on all chromosomes (except Y) using polymerase chain reaction(PCR).

Results: The total frequency of LOH in 42 gastric cancer was 27.7%. High frequencies of LOH (> or = 40%) were observed at loci D3S1067, D3S1577, D6S430, D15S205, D17S945, and D5S407, D2S136, D2S147, D13S175, D14S68, D8S279 loci had LOH frequency > or = 30%. Significantly more LOH cases were observed in the poorly differentiated type and the signet-cell type than in well differentiated type of gastric cancers (P = 0.00699 and 0.0001). The incidence of LOH in signet-cell cancer was even significantly higher than that in poorly differentiated gastric carcinomas(P = 0.0019). LOH was not found in 4 cases with well differentiated gastric cancer.

Conclusions: The most common LOH occurred at D3S1577, D3S1067, D5S407, D6S430, D8S279, D15S205 and D17S945 might imply the existence of potential tumor suppressor genes of gastric cancer.