Comparing with the untreated group, no apparent change of tumor cell viability was observed in PU.1-knockdown SC1 co-culture system, while significant reduction of tumor cell viability was observed in PU.1-overexpressing DOHH2 co-culture system upon lenalidomide treatment (P = 0.014, Fig. 3a), confirming that PU.1 correlated with lenalidomide sensitivity. This evidence concerns the gene SPI1 and neoplasm.