Carcinogenesis and the response of tumours to anticancer drugs.

Tumour development is the consequence of a multistep process involving the activation of oncogenes and loss of tumour suppressor gene function. The study of molecular alterations which accompany carcinogenesis and distinguish the tumour from its normal cellular counterpart, may provide a basis for the in vivo development of drug resistance and facilitate the rational design of anticancer drugs which exploit these differences. In this review we shal discuss some of the effects of carcinogen exposure in relation to how this may influence the response of a tumour to chemotherapy.