PPAT and central nervous system cancer: Fifteen human glioma cell lines were examined for their sensitivity to 1,3-bis(chloroethyl)-nitrosourea (BCNU, carmustine) and cis-dichlorodiamminoplatinum (cisplatin), the induction of DNA interstrand cross-linking (DNA-ISC) induced by the two agents and cellular O6-alkylguanine alkyltransferase (ATase) activity.