Recently we have performed whole-exome sequencing in primary CML patients before TKI administration and revealed five genetic variants typical for optimal responders (rs11579366 in ANKRD35, rs1990236 in DNAH9, rs176037 in MAGEC1, rs10653661 in TOX3, rs3803264 in THSD1) and two – for non-optimal responders (rs3099950 in MORN2, rs9471966 in PTCRA) [13]. The gene discussed is MAGEC1; the disease is chronic myelogenous leukemia, BCR-ABL1 positive.