Clinical studies of ABC-transporters contribution to the multidrug resistance of breast cancer
This review summarizes the clinical trials of the relationship of gene expression and protein ABC-transporters in breast cancer with the response to neoadjuvant chemotherapy (NAC) and survival of patients. In a large clinical material is considered the pre-treatment multidrug resistance (MDR) and adaptive MDR, that occurs in tumor cells during chemotherapy. Association pre-treatment MDR with NAC efficiency and survival is highly variable and not well-established. In all clinical trials, adaptive MDR showed a good association with NAC efficiency and survival of patients. The own results showed that 5-year distant metastasis-free survival was 73-78% and good response to NAC in patients with a decrease in ABC- expression. The up-regulation of these genes during NAC was related to a significant decrease (up to 50-55%) in metastasis-free survival and poor response to NAC. In the development of strategies to overcome MDR phenotype it is concluded based on the submitted clinical data.