This presentation reports on a study investigating the presence and cellular localization of individual families of cytochrome P450 enzymes, in both normal brain and primary brain tumours. The immunoreactivity of individual P450s was identified using light microscopic immunohistochemistry. In all cases, positive immunoreactivity for each P450 was identified in tumour cells and, generally, in positively staining cells, the immunoreactivity was strong. The presentation suggests that individual forms of P450 in brain tumours could be important therapeutically for the development of anti-cancer drugs that are activated by those forms of P450
