CYTOCHROME-P450 EXPRESSION IS A COMMON MOLECULAR EVENT IN SOFT-TISSUESARCOMAS

Two major xenobiotic metabolizing sub-families of cytochrome P450 (cyt ochrome P450 IA and cytochrome P450 3A) have been identified in soft t issue sarcomas. Cytochrome P450 1A was present in 70 per cent and cyto chrome P450 3A was present in 78 per cent of tumours, respectively. A high proportion (86 per cent) of those tumours which contained cytochr ome P450 1A or cytochrome P450 3A demonstrated co-expression of both s ub-families. In each tumour, cytochrome P450 immunoreactivity was iden tified in all tumour cells and there was no intra-tumour heterogeneity . These results indicate that expression of cytochrome P450 is a commo n molecular event in soft tissue sarcomas and that the presence of dif ferent sub-families of cytochrome P450 has implications both for the p athogenesis and for the treatment of these tumours. Cytochrome P450 ex pression may influence the intrinsic drug resistance of these tumours and also provide a molecular target for anti-cancer drugs which can be activated by cytochrome P450.