Study On The Correlation Between Genetic And Epigenetic Alterations Of Pten Gene In Soft Tissue Sarcomas

Objective: To detect the PTEN tumor suppressor gene in soft tissue sarcoma of the mutation frequency and promoter methylation status and to explore changes in soft tissue sarcoma in the role of tumor..Methods: (1) The use of PCR-SSCP method and DNA sequencing detected 86 cases of soft tissue sarcoma in the PTEN gene exons 5-8 mutation. (2)The use of matrix-assisted laser desorption ionization time-of-flight mass spectrometry (MALDI-TOF MS) analysis detected 60 cases of soft tissue sarcoma in the methylation status of PTEN gene and compared the 36 cases of specific translocation associated with 24 cases of non-related soft tissue sarcoma in the PTEN gene methylation differences. At the same time, in 20 cases of normal peripheral blood as normal controls. SPSS13.0 use all the data for statistical analysis package.Results: 1. PTEN gene mutation test results: 86 cases of soft tissue sarcoma detected two cases of PTEN gene exon 8 mutation (2.3%), and the remaining cases the mutation was not detected. Mutations in two cases of malignant fibrous histiocytoma (1/14,7%) and alveolar soft tissue sarcoma (1/4,25%). 2. PTEN gene methylation test results: (1) 60 cases of soft tissue sarcoma in the level of PTEN gene methylation (CpG methylation increases the number of units of PTEN gene methylation rate) was higher than normal controls (P<0.05), the average rate of methylation (21%) higher than the normal controls the average rate of methylation (3.5%) (P <0.05). (2) soft tissue sarcoma in the level of methylation PTEN₀01 than those in normal controls (P <0.05), the average rate of methylation was 17% higher than the normal average rate of methylation (4%) (P <0.05); PTEN₀03 soft tissue sarcoma in the level of methylation is higher than normal controls (P <0.05), the average methylation rate of 25 percent higher than the normal average rate of methylation (3%) (P <0.05). (3) specific translocation-related soft tissue sarcoma and non-correlation between soft tissue sarcoma of the level of PTEN gene methylation was no significant difference (P> 0.05). Specific soft tissue sarcoma translocation-related methylation level is lower than in non-related PTEN001 region soft tissue sarcoma (P>0.05), the average methylation rate of 20 percent higher than that of non-related soft tissue sarcoma of the average rate of methylation (15%) (P>0.05); specific translocation-related soft tissue sarcoma PTEN003 methylation levels in the region higher than that of non-related soft tissue sarcoma, the average methylation rate of 26 percent higher than that of non-related soft tissue sarcoma of the average methylation rate (23%) (P>0.05). (4) PTEN001CpG₉, CpG₁9 in specific soft tissue sarcoma translocation-related methylation lower than non-related soft tissue sarcoma (P <0.05).Conclusion: (1) The mutation of PTEN gene in soft tissue sarcoma is not a frequent event. PTEN gene exon 8 may be associated with malignant fibrous histiocytoma and alveolar soft tissue sarcoma which have a certain relationship between the occurrence. (2) The methylation of PTEN gene in soft tissue sarcoma is a frequent event., and there is no significant difference of the methylation of PTEN gene between the specific translocation associated and non-correlation soft tissue sarcoma.