Hyoung Yang et al. [86] have found that nitidine chloride (54) inhibits human oral squamous cell carcinoma (OSCC) by inhibiting the signal transducer and activator of transcription 3 (STAT3), and the main mechanism is the downregulation of myeloid cell leukemia-1 (MCl-1) protein in HSC-3 and HSC-4 by inhibiting the STAT3 pathway. The gene discussed is STAT3; the disease is oral cavity squamous cell carcinoma.