Methylation of the RASSFIA promoter in breast cancer

Value of the level of methylation of RASSF1A and WIF-1 in tissue and serum in neoadjuvant chemotherapeutic assessment for advanced breast cancer

This study assessed the clinical efficacy of the neoadjuvant chemotherapy TAC scheme in treatment of patients with locally advanced breast cancer, and the value of the level of Ras association domain family 1A (RASSF1A) gene methylation and the Wnt inhibitory factor (WIF)-1 gene in tissue and serum of patients in clinical outcome prediction. In total, 126 patients were consecutively selected to receive TAC scheme (docetaxel, pirarubicin/epirubicin and cyclophosphamide) for at least four cycles with the total effective rate. The incidence of complications, progression-free survival and survival rate were recorded. Tumor tissues and peripheral blood samples collected in this study was used to detect methylation positive rate of RASSF1A and WIF-1 by methylation-specific PCR method and the relative level of expression of RASSF1A and WIF-1 mRNA by reverse transcription PCR method. Of the 126 patients, there were 18 cases with complete response (CR), 32 cases with partial response (PR), 50 cases with stable disease (SD), and 26 cases with disease progression (PD) with a total effective rate of 79.37%. Comparison on baseline data of effective group and ineffective group showed no difference (P>0.05), and comparison on adverse reactions occurrence showed no difference (P>0.05). Progression-free survival of the effective group was prolonged with a significant increase in survival rate (P<0.05). Positive rates of RASSF1A methylation and WIF-1 in tissue and serum of the patients in the effective group were significantly lower than those in the ineffective group, but the mRNA of RASSF1A and WIF-mRNA was significantly higher than the ineffective group (P<0.05). The sensitivity of clinical outcome prediction using tissue RASSF1A methylation was 67.0%, the specificity 15.4%, positive predictive value 69.0% and negative predictive value 31.0%. The above-mentioned indexes of tissue WIF-1 were 76.0, 31.4, 72.2 and 27.8, respectively. The indexes of serum RASSF1A were 85.0, 50.0, 76.2 and 23.8%, respectively, and the indexes of serum WIF-1 were 94.0, 75.0, 81.0 and 19.0%, respectively. The receiver operating characteristic curve analysis suggested that the accuracy of clinical outcome prediction using tissue RASSF1A mRNA level was 0.812. The sensitivity 85.2%, the specificity 76.3% and the critical value 0.4256. These indexes of tissue WIF-1 were 0.833, 86.7%, 75.4% and 0.3562 for CR, PR, SD and PD, respectively. These indexes of serum RASSF1A were 0.864, 88.3%, 77.4% and 0.2564, respectively, and for serum WIF-1 were 0.882, 89.4%, 73.5% and 0.1562, respectively. In conclusion, the detection of RASSF1A and WIF-1 gene methylation and level of mRNA expression in tissue and serum of patients with locally advanced breast cancer has an important application value in predicting clinical efficacy of neoadjuvant chemotherapy of the TAC scheme.