PAK6 and chronic myelogenous leukemia, BCR-ABL1 positive: However, since the GSEA was performed using gene sets largely curated through mass spectrometry, synthetic peptides, and in vitro kinase experiments in non-leukemic cells, we then conducted cell cycle assays on K562 and IMR cells following PAK6 knockdown to investigate changes in cell cycle dynamics in the context of CML.