EVI1 overexpression collaborates with RUNX1 mutations in human MDSs. (A) EVI1 expression levels by qRT-PCR in CD34⁺ cells of clinical samples. Relative EVI1 expression was calculated as the ratio of EVI1 to GAPDH expression. RNA from normal BM CD34⁺ cells served as a control, and the RNA level was defined as 1. Data are expressed as mean ± standard deviation (SD). L-MDS, lower-risk MDS; H-MDS, higher-risk MDS; MT, mutation. (B) White blood cell (WBC) count and clinical course of a patient with high EVI1 expression. A 78-year-old male showed pancytopenia and blast cells in peripheral blood. BM examination showed hypocellular marrow with multilineage dysplasia and 16.5% of blast cells. Cytogenetic analysis showed 45,XY,add(3)(q13.2),-7. He was diagnosed with refractory anemia with excess blasts (RAEB-2) and received chemotherapy. However, his condition progressed to BM failure after chemotherapy and repeated severe infection. The blast population continued to increase gradually. Eight months after diagnosis, his WBC count started to increase, and he died with uncontrollable blast expansion 11.5 months after diagnosis.