CREB1 and acute lymphoblastic leukemia: The differences in sensitivity were reflected by CREB and phospho-CREB levels, with primary leukemic T-ALL cells showing high CREB expression or activity (T-ALL samples no. 1, 2, and 3) being more sensitive than those with low CREB and phospho-CREB levels (T-ALL sample no. 4) (Figure 7A).