1目的　研究胃癌组织中 P5 3基因和 ras基因的突变情况。 2方法　采用 PCR- RFL P技术 ,分析 41例胃癌标本中 P5 3基因和 ras基因的突变。 3结果　本组 41例中 ,12例 (2 9.3% )发生 P5 3基因突变 ,16例(39.1% )发生 ras基因突变 ,1例同时发生 P5 3基因和 ras基因的突变。4结论　 P5 3和 ras基因突变与胃癌的发生密切相关 ,在胃癌的发生中可能起重要作用 1 Objective To study the mutation of P5 3 gene and ras gene in gastric cancer. 2 Methods PCR-RFLP technique was used to analyze the mutations of P53 gene and ras gene in 41 gastric cancer samples. 3 Results In this group of 41 cases, 12 cases (2 9.3%) P5 3 gene mutation occurred in 16 cases (39.1%) ras gene mutation occurred in 1 case of simultaneous P5 3 gene and ras gene mutations. 4 Conclusion P5 3 and ras gene mutations and gastric cancer is closely related to the occurrence of gastric cancer may play an important role