The role of tumour microenvironment-driven miRNAs in the chemoresistance of muscle-invasive bladder cancer–a review

•Resistance to chemotherapy in MIBC is facilitated by the tumour microenvironment.•miRNAs are the underlying master regulators of chemoresistance in MIBC.•The lack of parallel epigenetic findings explains the heterogeneity in bladder cancer. Successful treatment for muscle-invasive bladder cancer is challenged by the ability of cancer cells to resist chemotherapy. While enormous progress has been made toward understanding the divergent molecular mechanisms underlying chemoresistance, the heterogenous interplay between the bladder tumour and its microenvironment presents significant challenges in comprehending the occurrence of chemoresistance. The last decade has seen exponential interest in the exploration of microRNA (miRNA) as a tool in the management of chemoresistance. In this review, we highlight the miRNAs involved in the tumour microenvironment crosstalk that contributes to the chemoresistance in bladder cancer. Decrypting the role of miRNAs in the interplay beholds scope for future clinical translational application in managing the long-standing concerns of chemoresistance in muscle-invasive bladder cancer.