However, PBMC of de novo CP-CML patients and BP-CML patients demonstrated no expression of p-ATM and predominantly no expression of p-CHK2 (apart from strong expression of p-CHK2 in BP-CML#2), which was in contrast to the presence of relatively high levels of DNA damage in these cells as evidenced by γH2AX foci analysis. Here, CHEK2 is linked to chronic myelogenous leukemia, BCR-ABL1 positive.