These previous reports and our in vitro findings from the current study, including 1) increase in HSP90 level or constitutive activation of Src increase TYMS expression and 2) pharmacologic suppression of HSP90 or Src decreases TYMS mRNA and protein expression suggest that up-regulation of TYMS expression in HCT116/R cells were through enhanced HSP90 and Src activities and might be a fundamental mechanism by which colon cancer cells acquired EMT phenotypes and 5-FU resistance. The gene discussed is TYMS; the disease is malignant colon neoplasm.