Since the binding sites of these two RBPs, i.e., KSRP and hnRNP A1, overlap in the terminal loop of pri-let-7a-132, the competition between KSRP and hnRNP A1 for pri-let-7a processing may contribute to the cellular expression of let-7a and to tumor progression in various cancers expressing let-7a. The gene discussed is KHSRP; the disease is cancer.