Rapidly upregulated PCNA gene expression after hyperthermic chemotherapy with 5-FU was observed in HT-29 cancer cells, whereas no changes were visible after normothermic incubation with the substance (0.5 hours after treatment at 41°C: FD 9.8 and 43°C: FD 19.4) (Figure 7A, top). The gene discussed is PCNA; the disease is cancer.