RESUMEN
ObjectiveTo understand the characteristics of mutations in BCR-ABL1 kinase domain mutation,these chronic myeloid leukemia (CML) and Ph positive acute lymphoblastic leukemia (ALL)patients who got imatinib treatment had poor effect.MethodsTotally 177 CML patients and 33 Ph( + )ALL patients were selected at Beijing Dao-Pei Hospital from Sep.2007 to Dec.2010.All of them were Chinese patients.Totally 243 bone marrow or peripheral blood specimens were collected from the patients,who had early effect,then resistance emergenced,or for more than 3 months of poor efficacy.Extracted total RNA from the specimens' nuclear cells,reversed transcription to cDNA.Amplified the whole span of BCRABL1 fusion kinase gene by nest PCR (from 242 to 493 amino acid coding sequence),used the type AB3130XL gene sequencing instrument determinate the gene sequence of ABL1 kinase region and then used the Variant Reporter V1.0 software to analyze the results of gene mutations.ResultsThirty-two kinds of different mutations were detected of ABL1 gene mutations,accounting for 34.2％ (83/243 cases).Among them,the T315I was 12％ (10/83),mutation rate was the highest,followed by Y253H was 11％ (9/83),G250E was 7％ (6/83),E255K was 7％ (6/83),M351T was 6％ (5/83),E459K was 5％ (4/83) ;Q252H,D276G,F317L,E355G,F359V,H396R were all 4％ (3/83).Three cases of insertion mutations were found,including 2 cases of 357-358insk,1 case of V304RfsX17.Seven patients had found existence two or more point mutations.The multiple drug resistance mutations might exist in the same leukemia clone.The same individual was not only contain common resistance mutations,but also rare point mutations,insertion mutations.The mutations might be lead to loss of kinase activity.ConclusionsUnder the imatinib drugs pressure,the ABL1 gene mutation in leukemia cells appears randomly,and results in different resistant clones.Different resistant clones can coexist in the same patients in vivo; resistant clones not only contain point mutations,but also contain inserted deletion mutations.