TK1 and pancreatic neoplasm: Expression of these genes, which are involved in 5-FU conversion to FdUMP, also correlated with expression of the FdUMP efflux transporter ABCC5 (TK1 and ABCC5 r = 0.78, p = 0.001 and TYMP and ABCC5 r = 0.86, p < 0.0001) in pancreatic tumour.