Overexpression of sortilin expression was observed in vivo in 5‐FU‐resistant tumours derived from both cell lines and in vitro (at the mRNA and protein levels) in whole‐cell lysates of 5‐FU‐resistant WiDr, SW620 and primary cultures obtained after short‐ (72 hours) or long‐term (one month) treatments. This evidence concerns the gene SORT1 and neoplasm.