To further clarify whether the activated CD44 in mutated p53 HCT116 cell lines was responsible for chemoresistance, we knocked down the expression of CD44 by transfection of siRNAs specifically targeted to CD44 in R273H and R248W of p53 HCT116 tumor cells to examine the changes involved in 5-FU tolerance. This evidence concerns the gene TP53 and neoplasm.