Abnormal Expression Of P16 Protein In Gastric Carcinoma And Its Significance

The tumor suppressor gene P16 was found and cloned by Serrano first in 1993, locating the No.9th chromosome (9P²¹), whole long 8.5 kb. The protein of P16 is a single chain multi-peptide of 15.84ku and contains 148 amino acids. The protein is a kind of cell cycle dependent inhibitor. It can combine with the CDK4/ CDK6 with the cyclinD1 competition, and repress the activity of CDK4/ CDK6. P16 mainly regulates the cell cycle in the conversion process of G1 period toward S period. Some research express that the imperfect expression of P16 gene related with the occurrence of various tumors. At the aspect of the relation of stomach cancer and P16 gene, domestic and international scholars thought that the expression imperfection of P16 gene is the later period affairs of the stomach cancer and P16 gene was related with the biology characteristic of the stomach cancer, but some rift still existed. Since the first article about the protein of P16 reported in China in May 1996, some research has been done, but the research is still not thorough. And the relation research of protein of P16 and the stomach cancer was less, although people had some consensuses, still had the rift. Most local scholars thought that the expression of P16 protein more low the differentiation of stomach cancer more bad and the malignant degree more high. But there were still rifts about the relations of protein of P16 and the organization type of stomach cancer, pTNM, the depth of invasion, the lymph node metastasis and the distant metastasis. This experiment objective was to study and discuss the relations between the expression of P16 in gastric carcinoma (GC) and the clinical characteristics of GC by S-P immunohistochemica1 staining. We got the following results though this experiment: â‘ The positive ratio of P16 expression in NGT was 80%, the ratio in GC was 44.44%. There was significant difference between them (p<0.05). â‘¡The positive ratio of P16 expression in male cases was 40.91%, 52.63% in female cases, without significant difference between them (0.250.05). â‘£The positive ratio of P16 expression in cases with ≤45y was 28.57%, 37.50% in 46⁶5y, 70.59% in >65y. There was significant difference between cases with ≤45y and cases with >65y (p<0.05). ⑤There was significant difference in the positive ratio of P16 expression between cases with high differentiation and moderate-low differentiation (64.00%, 31.58%, p<0.05). â‘¥Between cases with invasion through muscle and not, there was significant difference (36.36%, 63.16%, p<0.05). ⑦Significant differences can be seen between cases with lymph node metastasis and not (32.50%, 65.22%, p<0.05). The experiment result showed that the positive ratio of P16 expression in NGT was 80%, the ratio in GC was44.44%. There was significant difference between them (p<0.05). It was thus clear that the expression imperfection of the gene of P16 was an important factor that caused stomach cancer. We discovered it by a contrast analysis that there was not significant difference between the positive ratio of P16 expression and sex, and without significant difference between the positive ratio of P16 expression and the place where GC lied (p>0.05). The microcosmic environment was different in cardiac part, in fundus and body of stomach and in pyloric part, so there were different hurt factors in them: stomach acid mainly in cardiac part;stomach acid and protein enzyme mainly in fundus and body of stomach;stomach acid, protein enzyme, countercurrent of bile and Helicobacter pylori infection in pyloric part. So we think that the P16 expression imperfection was indiscriminate in stomach cancers which developed under different hurt factors. This still need the further confirmation. There were remarkable differences between high and moderate-low differentiation, and also between invasion through muscle and not. Significant differences can be seen between lymph node metastasis and non. P16 gene controlled indirectly E2F through the P16-cyclinD1-CDK4/6-Rb-E2F path. This was the main reason for the relation of P16 gene and stomach cancer. Because E2F can control genes that can code DNA replication and regulate the cell cycle, it developed important function in the conversion process of G1 period...