KB-V1 is a multidrug-resistant (mdr) subclone derived in 1985 from KB-3-1 which itself is a derivative of the 1951 established HELA (31-year-old black woman); cells express strongly mdr1 mRNA and protein; the cell line will only be distributed to non-profit institutions, commercial entities may apply for a license at the NIH/NCI Technology Transfer Cernter, Rockville, MD, USA, phone (301)435-3111