Focusing on CML, one report showed that K-562 cells induced to imatinib resistance (IR-K562) showed overexpression of COX-2 and PTGS2. These IR-K-562 cells were more sensitive to celecoxib alone or in combination with imatinib than the original K-562, imatinib sensitive cells, suggesting that PTGS2 induction is related to resistance to imatinib (25). Here, PTGS2 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.