| Background and AimsGastric carcinoma(GC)is one of the most commom malignancies,accounting for the second of all cancer death all over the world. The development and progression of cancer is an very complicated process involving several biological events such as activation of oncogenes,inactivation of tumor suppressor gene and abnormal expression of some apoptosis-related genes,etc. The role of cell cycle regulation-related proteins in carcinogenesis, progression and prognosis of tumors has caused the concern of oncologists. Better knowledge of the changes in gene expression that occur during gastric carcinogenesis may lead to improvements in diagnosis, treatment and prevention.PITX1 is the tumor suppressor gene recently discovered. The P53 gene is the most frequently mutated gene in human cancer. We detected the expression of PITXland mutant P53 genes and proteins in different pathological lesions of gastric mucosa to study their roles in carcinogenesis,development and metastasis of gastric carcinoma in order to provide new theoretical foundation for forecasting the early diagnosis, prevention and clinical treatment, judging prognosis of gastric carcinoma.Material and Methods 122 cases of gastric cancer specimens were collected from July 2009 to March 2010.The 43 cases with chronic superficial gastritis were chosed as control group.46 cases of premalignant lesion tissue specimens underwent endoscopy were collected (27 chronic atrophic gastritis with intestinal metaplasia,19 dysplasia). None of the patients had received neoadjuvant chemotherapy or radiation therapy before surgery, and they were all confirmed pathologically. The PITX1 and mutant P53 protein expression was evaluated by immunohistochemical staining.The expression of PITX1and mutant P53 mRNA was detected by using RT-PCR.2 Statistical analysis:The data were analyzed by solfware SPSS 10.0 continuous variables were tested by t test. The mean varied was compared with single-factor analysis of variance. Chi-square test was used to compare categorical variables. Difference was considered as statistically significant when P<0.05.Results1 The expression average quantity of PITX1mRNA The expression average quantity of PITX 1 mRNA were 0.4212+0.038,0.3363±0.048,0.3189±0.027,0.1055±0.032 in chronic superficial gastritis,chronic atrophic gastritis with intestinal metaplasia,dysplasia and gastric carcinoma, respectively.There were significant differences (P<0.05) when gastric gastric carcinoma group compared with dysplasia group. There were also significant differences (P<0.05) when they compared with normal gastric tissue and chronic atrophic gastritis with intestinal metaplasia separately.2 The expression average quantity of mutant P53mRNA The expression average quantity of muant P53mRNA were 0,0.336±0.043,0.563±0.052,0.613±0.071 in chronic superficial gastritis,chronic atrophic gastritis with intestinal metaplasia,dysplasia and gastric carcinoma, respectively.It presented with progressive tendency for the expression of mutant P53mRNA. There were no significant differences (P> 0.05) when gastric gastric carcinoma group compared with dysplasia group. There were significant differences (P<0.05) when gastric gastric carcinoma group compared with chronic superficial gastritis and chronic atrophic gastritis with intestinal metaplasia separately.3 (1) The expression of PITX 1 protein The positive rates of PITX 1 protein were 100%,56%,53% and22.7% in chronic superficial gastritis,chronic atrophic gastritis with intestinal metaplasia,dysplasia and gastric carcinoma, respectively.The positive expression rates of PITXl protein in gastric carcinoma group were significantly lower than those in other groups.The differences had statistical significances (P<0.05). (2) The relationship between the expression of PITX1 protein and the clinicalpathological features in gastric carcinoma group.The expression of PITXlprotein was related to infiltration degree (P<0.05), but irrelevant to sex, age and lymph node metastasis (P>0.05)4 The expression of mutantP53 protein The positive rates of mutant P53 protein were 0,41%,68%,72%in chronic superficial gastritis,chronic atrophic gastritis with intestinal metaplasia,dysplasia and gastric carcinoma, respectively. The positive expression rate of mutantP53 protein in gastric carcinoma group and dysplasia group were significantly higher than that in chronic superficial gastritis and chronic atrophic gastritis with intestinal metaplasia group. The differences had statistical significances (P<0.05). (2) The relationship between the expression of mutantP53 protein and the clinicalpathological features in gastric carcinoma group The expression of mutant P53 protein was related to lymph node metastasis (P<0.05), but irrelevant to sex, age and infiltration degree (P> 0.05)Conclusions1. The reducing tendency for the expression of PITX1 are common in carcinogenesis of gastric cancer.And expression level of PITX1 protein was related infiltration degree, which suggest that PITX1 involved in the process of carcinogenesis and development of gastric carcinoma.2. Expression of mutant type P53 was moderately increased in chronic atrophic gastritis with intestinal metaplasia and dysplasia tissues and significantly increased in gastric cancer, which suggest that mutant type P53 may play a role in the early stage of human gastric carcinogenesis.Expression of mutant type P53 was related to lymphnode metastasis, which suggest that mutant type P53 was related to carcinogenesis, development and metastasis of gastric carcinoma.3. The silent expression of PITX1 and the increased expression of mutant type P53 may play an important role in gastric cancer pathogenesis. Their combined detection can contribute to the earlier diagnosis and treatment of gastric cancer. |
PDF Full Text Request