Testing Of TβR Ⅰ, Ⅱgene Methylation Status In Renal Cell Carcinoma And Its Clinical Significance

Objective: Renal cell carcinoma is one of the most common malignant tumors in the urinary system. The incidence rate of cancer ranks second in the urinary system, among which renal cell carcinoma is the most common. In recent years, the tendency of a gradual increase in the incidence of renal cell carcinoma is clearly shown, and people who get this cancer become younger and younger. As the incidence is occult, patients with early stage don't attract attention or get timely treatment, which results in the delay condition that seriously affects the survival rate and worsens the quality of patients'life. Cancer metastasis is an important factor leading to death of patients. This process involves cells'disengagement from the primary foci, infiltration surrounding tissue into the circulatory and lymphatic systems, transfer to distant organs, and the proliferation of the formation of metastasis. The pathogenesis of renal cell carcinoma is not yet clear, so it is necessary to study its pathogenesis in order to reduce morbidity and mortality in renal cell carcinoma.The research object is renal clear cell carcinoma. The study is to testing of TβRⅠ,Ⅱgene methylation status and its clinical significance. A better understanding of the correlation of two in renal clear cell carcinoma occurrence, development, invasion and metastasis will be shown. The study is also to seek the potential clinical significance of treatment targets, so as to provide a new theoretical and experimental basis for the pathogenesis of renal cell carcinoma, gene therapy and clinical prognosis, etc.Methods:1. Methylation-specific PCR (MSP) is applied to detect 43 cases of renal clear cell carcinoma, 43 cases of adjacent normal tissues TβRⅠ, andⅡgene methylation status. 2. PV immunohistochemistry (IHC) is applied to detect 40 cases of renal clear cell carcinoma, 28 cases of adjacent normal tissues TβRⅠ, andⅡgene protein expression.3. SPSS13.0 was applied to analyze the results of experiment.Results:1. Methylation status:(1) TβRI gene was methylated in 22 of 43(51.2%) in RCCC specimens and 17 of 43(39.5%) in adjacent normal tissues, but there was no significant difference between them (P>0.05). In renal clear cell carcinoma, Methylation frequencies of TβRI gene had difference in different age and gender groups, but no significance (P>0.05). Methylation frequencies of TβRI gene in Tumor diameter≤7cm group 51.6% was higher than that in tumor diameter> 7cm group 50.0%, and methylation frequencies of TβRI gene in poor differentiation group 22.2% was lower than high differentiation group 58.8%, but all of them did not show significant difference (P>0.05).(2) TβRⅡgene in RCCC group and adjacent normal group in the methylation rates were 58.1% (25/43) and 34.9% (15/43). The difference was statistically significant, that is, RCCC group was significantly higher than the rate of methylation adjacent normal group (P<0.05). Methylation frequencies of TβRII gene had difference in different age and gender groups, but no significance (P>0.05). Methylation frequencies of TβRII gene in Tumor diameter≤7cm group 54.8% was lower than that in tumor diameter>7cm group 66.7%, and methylation frequencies of TβRII gene in poor differentiation group 33.3% was lower than high differentiation group 64.7%, but all of them did not show significant difference (P>0.05).(3) Methylation analysis of two genes: TβRI and TβRII genes were methylated simultaneously in 20 cases of RCCC tissues, and in 12 cases of adjacent normal tissues. Carcinoma of simultaneous methylation rate was 46.5% higher than the adjacent normal group 27.9%, but the difference was not statistically significant (P>0.05).2. Protein expression: (1) PV immunohistochemistry was applied to detect TβRI in 40 cases of renal clear cell carcinoma and 28 cases of adjacent normal tissue protein expression. Positive expression rates were 52.5% (21/40) and 89.29% (25/28), Both of them have a statistically significant difference (P<0.05).(2) PV immunohistochemistry was applied to detect TβRⅡin 40 cases of renal clear cell carcinoma and 28 cases of adjacent normal tissue protein expression. Positive expression rates were 60.0% (24/40) and 92.86% (26/28), Both have a statistically significant difference (P<0.05).(3) In renal clear cell carcinoma, TβRⅠand TβRⅡprotein expression has nothing to do with the patient's age and sex (P>0.05), and tumor size and tumor differentiation associated (P<0.05).3. The relationship between protein expression and methylation:In the TβRⅠprotein expression positive RCCC tissues and its methylation-positive rate was 66.7% (14/21); in the TβRⅠprotein expressionnegative RCCC tissues and its methylation-positive rate was 36.8% (7/19). The difference was not statistically significant (P>0.05). In the TβRⅡprotein expression positive RCCC tissues and its methylation-positive rate was 70.8% (17/24); in the TβRⅡprotein expression negative RCCC tissues and its methylation-positive rate was 43.8% (7/16). The difference was not statistically significant (P>0.05).Conclusions:1. The methylation incidence of TβRI gene had no significant difference between RCCC group and corresponding normal group, and there was no relationship between its methylation and clinical data. They indicated that the promoter methylation of TβRI gene may be not related to oncogenesis and development of RCCC. The methylation incidence of TβRII gene in RCCC group was significantly higher than that in adjacent normal group, but there was also no relationship between its methylation and clinical data, which indicated that the promoter methylation of TβRII gene may be related to oncogenesis of RCCC, but not related to development of RCCC.2. TβRⅠand TβRⅡin the RCCC group and adjacent normal group, simultaneous methylation rate was not statistically significant, This indicated that simultaneous methylation of two genes maybe had no relation to oncogenesis of RCCC.3. TβRⅠand TβRⅡgenes protein expression in the RCCC was significantly lower than the adjacent normal group, indicating that abnormal protein expression of two genes may be related to oncogenesis of RCCC.4. In renal clear cell carcinoma, TβRⅠ, TβRⅡprotein expression has nothing to do with the patient's age and sex,and tumor size and tumor differentiation associated,which suggested that TβRⅠ, TβRⅡprotein expression may be involved in the reduction or absence of renal clear cell carcinoma of the development, invasion and metastasis.5. In the protein expression positive-negative RCCC tissues TβRⅠ, TβRⅡpositive rate of methylation difference was not statistically significant, which indicated that methylation may not be the main reason leading to abnormal protein expression.