HSP combined with 5-fluorouracil (5-FU) was more effective rather than a single use of the drug in Eca-109 cell line and a xenograft mouse model of esophageal cancer through down-regulating Bcl-2 with simultaneously increasing Bax, caspase-3, caspase-9 more effectively than did 5-FU only and reduced cancer cell invasion with cell proliferation through mitigating PI3K/AKT signalling pathway [113]. The gene discussed is CASP9; the disease is cancer.