And the leading hypotheses include direct gustatory cytotoxicity [35,36], oral mucositis and zinc deficiency [37,38].In addition, a study of mice treated by vismodegib, a targeted drug for the treatment of basal-cell carcinoma, indicated that vismodegib can cause a significant reduction in the size of taste buds and the number of taste cells per taste bud, as well as the decrease also included Ki67 and Shh (Sonichedgehog) expressing cells in taste buds. Here, SHH is linked to Zinc deficiency.