Objective To explore the mechanism of the decreased expression of connexin gene (Cx) 43 in human gastric cancer. Methods Detections on mutation of Cx43 coding region in 30 cases of human gastric cancer and control normal tissues were undertaken by means of reverse transcription-polymerase chain reaction-single strand conformation polymorphism (RT-PCR-SSCP). Results [WTBZ]No point mutation of Cx43 was found in 30 cases with human gastric cancer. Conclusion The decreased expression of Cx43 was not related to the mutation of coding region, but to the non-coding sequence, especially the 5' regulation sequence. The results were helpful for the further studying of the relationship between gastric cancer and connexin gene. The RT-PCR-SSCP is effective, fast, inexpensive and radiationless for mutation detection, which may be a means of gene diagnosis for gastric cancer.

Objective To study the expression of connexin (Cx) genes and the effects of a variety of inducers on the expression changes of Cx and mutations of Cx coding sequences in human gastric cancer. Methods Northern Blot, RT PCR and PCR single strand conformational polymorphism were used. Results 1.There were regular expression patterns of Cx genes in human normal gastric epithelium, paracancerous tissues and gastric cancers. 2.RA and DMSO can induce the expression of Cx43 in gastric cancer and decrease of Cx46 expression by RA and TPA induction. 3.There was no any mutation in Cx43 coding sequences. Conclusion 1.Cx32 gene may be a specific gene in genome of gastric epithelium constructing gap junctional intercellular communication. 2.Cx43 is a inducible gene in gastric cancer cells. 3.The down regulation of Cx43 expression is not caused by mutation of Cx coding sequences in human gastric cancers. 4.The authors proposed a hypothesis on the variation of expression of Cx genes in human gastric cancer.