STAT3 and squamous cell carcinoma: HDACi inhibitors such as Trichostatin A (TSA) and sodium butyrate (NaB) exert their effects on the inhibition of tumor stem cells (CSCs) in squamous cell carcinoma by regulating the acetylation of nonhistone proteins, thereby affecting several transcription factors including p53, STAT3, and other transcription factors, and can enhance the sensitivity of tumor cells to drug therapy [13–15].