Study On Clinicalpathology Between Epigenetic Alterations And Expression Of Pten Gene In Gastric Carcinoma

Obiective:To investigate the frequency of the mutation of tumor suppressor gene PTEN and the expression of PTEN protein.; explore there relationship, compare with, the difference of PTEN gene between diferrent gastric adenocarcinoma, investigate the association of the expression of PTEN protein and PTEN gene mutation with the TNM classification and histopathology classification of gastric carcinoma, investigate the role of PTEN gene in the mechanism of gastric carcinoma and evaluate their role in the development of gastric tumor.Methods:(1) Immunohistochemistry (S-P) was used to detect the expression of PTEN protein in 105 case of gastric carcinoma tissues and their adjacent normal gastric tissues(2) Use PCR-SSCP and DNA sequencing technology to detect the mutation in exon 5 and 8 of PTEN gene in 105 gastric carcinoma tissues, all data analysis was used by SPSS 16.0Results:(1) The miss rate of the expression of PTEN protein in gastric carcinoma tissues(43.80%) was higher than that in normal gastric tissues(7.61%). The miss rate of PTEN protein correlated significantly with the differentiation degree, infiltration depth, lymph node transfer and clinic stage(P<0.05), but not significantly with sex and age(P>0.05).The miss rate of the expression of PTEN protein in gastric carcinoma tissues was:52.77% for gastric signet-ring cell carcinoma,40.9% for gastric poorly differentiated adenocarcinoma,46.42% for gastric mucinous adenocarcinoma, and 26.31% for moderate and well differentiated adenocarcinoma. (2) 25 mutations was detected in 105 gastric carcinoma tissues:19 mutations in exon 8(18.9%),6 mutations in exon 5(5.71%). The mutation loci was concentrated in the codon 153,161,162, 332,335。(3) The frequency of PTEN mutation was 25%(9/36) in gastric signet-ring cell carcinoma,25%(7/28) in gastric mucinous adenocarcinoma,40.9%(9/22) in gastric poorly differentiated adenocarcinoma. The frequency of PTEN mutation in gastric carcinoma(23.8%,25/105) was significantly lower than that in normal gastric tissues(P<0.05). (4) The frequency of PTEN gene mutation was no significantly correlation with that of the miss rate of PTEN protein in gastric carcinoma. The miss rate of the expression of PTEN protein was 33.33%(3/9) in gastric signet-ring cell carcinoma which had PTEN gene mutation,57.14%(4/7)in gastric mucinous adenocarcinoma,66.66%(6/9) in gastric poorly differentiated adenocarcinoma, and the 84% placenta percreta were invaded in the cases which had PTEN gene mutation, 64% for lymph node transfer,60% in the early phase of clinic stage, and close to the biological behaviour of gastric signet-ring cell carcinoma.Conclusion:(1)the miss rate of the expression of PTEN protein in gastric carcinoma tissues was correlated closely with differentiation degree, infiltration depth, lymph node transfer and clinic stage. and correlated with the occurrence and development of gastric carcinoma (2) The mutation of PTEN gene was not significantly correlated with the pathologic type, clinic stage and lymph node transfer, but the frequency of PTEN gene mutation had the elevated tendency in accordance with the decrease of differentiation degree. It indicated that the mutation of PTEN gene usually happened in the case who had worse biological behaviour, and provide referenced value for clinic early diagnosis, therapy and intervention. (3) The miss rate of the expression of PTEN protein was significantly higher than that of PTEN gene mutation. It indicated that PTEN gene mutation was not the uniqueness cause of the deletion expression of PTEN protein in gastric carcinoma. (4) The mutation of PTEN gene was closed to the biological behaviour of gastric signet-ring cell carcinoma, and had some correlation with gastric signet-ring cell carcinoma.