BID and esophageal squamous cell carcinoma: The Western blot results revealed that PPT decreased the expression of Bid, Mcl-1, and Bcl-2, and increased the expression of Bax, apoptotic protease activating factor-1(Apaf-1), and cleaved Poly (ADP-Ribose) Polymerase (c-PARP) in the ESCC cells.