Difference Expression And Significance Of HMLH1and HMSH2Gene In Tibetan, Hui And Han Patients In Qinghai District With Gastric Cancer

QObjectives To detect the expression level of mismatch repair genes proteinshMLH1and hMSH2in Tibetan, Hui and Han patients with gastric cancer and tocompare them with those of control group. The similarities and differences of the twoproteins in three nationalities as well as the significances were researched inperspective of molecular biology. Impact of two proteins on the occurrance anddevelopment of gastric cancer was investigated in favor of objective basis for thepossible genetic susceptibility in different nationalities.Methods Collected specimens of gastric cancer by Gastroscopy forceps andconcurrent non-atrophic gastritis and slight chronic atrophy gastritis from theAffiliated Hospital of Qinghai University during April2010to October2011. Allspecimens were diagnosed by department of pathology. The specimens were firstfixed in10%neutrality formalin solutions, then embedded by paraffin, and finallysliced into4μm continuous sections. Select30cases including16males of gastriccancer specimens in each of Tibetan, Hui and Han Chinese patients who are no bioodrelationship in Qinghai Province. Meanwhile, select30cases including16males ofnormal non-atrophic gastritis and slight chronic atrophy gastritis specimens of eachnationality at the same period as the control group. Ages and sexes in two groups werenot significantly different. Immunohistochemistry method to detect the expressionlevel of mismatch repair genes hMLH1and hMSH2of the three nations. Expressiondifferences of the two proteins make use of χ~2test.Results①The positive rates of hMLH1expression were33.33%、66.67%、70.00%，in Tibetan, Hui and Han gastric cancer tissues while93.33%、86.67%、90.00%in non-atrophic gastritis tissues, respectively. The positive rates of expression were lowerthan those in non-atrophic gastritis tissues. Meanwhile, the positive rate in TibetanChinese gastric cancer tissues was significantly lower than those in Tibetan and Huinon-atrophic gastritis tissues, while the positive rates between Hui and Han Chinesetissues were not significantly different. Positive rates have no significant difference ingastritis tissues.②The positive rates of hMSH2expression were93.33%、90.00%、96.67%in Tibetan, Hui and Han Chinese gastric cancer tissues and50.00%、50.00%、43.33%in non-atrophic gastritis tissues respectively. The positive rates of hMSH2expression of gastric cancer tissues in three nationalities were all higher than those ofnon-atrophic gastritis and slight chronic atrophy gastritis tissues and the positive ratesin gastric cancer tissues and non-atrophic gastritis tissues of each nation were notsignificantly different.Conclusions In Qinghai district, the positive rates of hMLH1expression in gastriccancer tissues were significantly lower than those in non-atrophic gastritis and slightchronic atrophy gastritis tissues in which the positive rate in gastric cancer tissues ofTibetan patients was significantly higher than those of Hui and Han Chinese patients.It indicates that, compared with the Hui and Han, mismatch repair gene hMLH1of theTibetan is more difficult to generate errors in the repair replication process. Thepositive rate of hMSH2expression in gastric cancer tissues in Qinghai district washigher than those in non-atrophic gastritis and slight chronic atrophy gastritis mucosatissues. The positive rates in gastric cancer tissues and non-atrophic gastritis tissues ofthe three nations were not significantly different. It reveals that the rise of hMSH2expression is concomitant with the occurrence and development of gastric cancer,thepossibility of the commonly clinical tumor marker needs further investigations.