DHFR and neoplasm: The detected expression pattern of genes related to drug resistance and metabolism,DNA damage and repair and cell cycle regulation (ABCC3,TOP2A, DHFR, NAT2,BRCA1, BRCA2, CCND1,CDK2 and CDK4) seems to be in line with our resultsobtained in the cytotoxicity analyses for G113 and G116 tumours presentingenhanced drug resistance in adherent serum-supplemented culture.