SIRT1 and chronic myelogenous leukemia, BCR-ABL1 positive: SIRT1 expression promoted the acquisition of BCR-ABL mutations and SIRT1 knockdown supressed genetic mutations of hypoxanthine phosphoribosyl transferase (HPRT) in the KCL22 CML cell line, suggesting that inhibition of SIRT1 may be able to overcome drug resistance.