The knockdown of DPP9 in oral squamous cell carcinoma cells increased cell growth via FAP-α [45], whereas the overexpression of DPP9 in Huh-7 and HepG2 cells reduced proliferation and increased apoptosis independent of its enzymatic activity by interacting with HRAS [46]. The gene discussed is DPP9; the disease is oral cavity squamous cell carcinoma.