Figure 4b shows the results of mRNA expression of cell cycle-regulation genes (ABL-1, BIRC-5, KNTC-1, MCM2, MKI-67, PCNA, and E2F4) related to NaB-treated HCT-116, HT-29, and COLO-205 cancer cell lines. The gene discussed is E2F4; the disease is cancer.