High Expression of MDR1 is Correlated with Poor Prognosis for Common Malignancies

The purpose of this study is to detect the relative expression level of Multi-drug resistance gene (MDR1) in common tumor malignancies, and evaluate the prognostic value of MDR1 expression in common malignancies. mRNA relative expression levels of MDR1 were detected byreal-time quantitative polymerase chain reaction (RT-qPCR) in tumor, adjacent, and non-cancerous tissues. The tumor markers were detected with COBAS 6000. The prognostic value of relative MDR1 expression level in malignant tumors was investigated by univariate survival and Cox regression model analyses, and survival times were compared using the log-rank test. At the same time, through receiver operating characteristic (ROC) curve analysis, their diagnostic threshold values were calculated. MDR1 expression levels were the highest in malignant tumor tissues, followed by adjacent tissues, and the lowest in non-cancerous tissues. Differences in expression level between varying degrees of differentiation and/or lymphatic metastasis, as well as variations in negative and positive expression between survival and recurrence times, were statistically significant. The level of tumor markers at 6 months after operation was significantly lower than that before operation in recurrent/non-recurrent and MDR1 positive/MDR1 negative group. There was a significant correlation between MDR1 expression and tumor markers (CA125 and CA153), regardless of whether recurrence was involved in PEOC and breast cancer. Multivariate logistic regression indicated that relative MDR1 expression levels in patients of the positive-group survival curves were lower than those in patients of the negative-group curves. High MDR1 expression is associated with clinicopathological features in malignant tumor patients. The detection of MDR1 expression combined with tumor markers can improve the sensitivity and specificity of predicting postoperative recurrence (especially breast cancer and PEOC).