Specifically, we previously demonstrated a consistent synergistic mechanistic interaction between HDACis and fluoropyrimidines on the basis of the specific modulation of critical enzymes involved in fluoropyrimidine metabolism, such as thymidylate synthase and thymidine phosphorylase, in colorectal [16, 17], breast [33], and head and neck cancers [34]. The gene discussed is TYMP; the disease is head and neck cancer.