MYD88 and breast cancer: The role of miRNA-149-5p/MyD88 in the regulation of PTX resistance was investigated by the transfection of breast cancer cells with MDA-MB-231 (231) and MDA-MB-231/PTX-resistance (231/PTX) with lentiviruses carrying the MyD88 gene, shRNA specific for MyD88, the miR-149-5p gene, and shRNA specific for miR-149-5p.