DDIT3 and neoplasm: In the cluster group with longer PFS, the enrichment of GO:BP terms related to DNA damage response in the genes down-regulated at the six-week timepoint compared to the initial timepoint suggests the selective pressure of CHOP treatment on the tumor cell population selects for cells with reduced DNA damage response and further suggests down-regulated DNA damage response is a driver of resistance to CHOP in the cluster group with shorter PFS.