XPB is tyrosine-phosphorylated and possibly forms a complex with P210 BCR-ABL in CML cells. Total cell lysates (a), anti-XPB immunoprecipitates (b), and anti-phosphotyrosine immunoprecipitates (c) from human leukemic cell lines HL60 (derived from Ph1-negative acute promyelocytic leukemia) (lane 1), two cell lines from Ph1-positive ALL [TOM-1 (lane 2) and ALL/MIK (lane 3)] (28), three cell lines from Ph1-positive CML in blastic crisis [K562 (lane 4), SKH-1 (lane 5), and KCL-22 (lane 6)] (7) were subjected to anti-ABL (a, Upper and c, Lower), anti-XPB (a, Upper, b, Middle, and c, Upper), anti-PY (b, Top), and anti-p62 (b, Bottom) Western blot analyses.