ChemoScreen uses good cell culture practices to develop its chemo-resistant cell lines. Practices include (1) dedicated cell culture medium for each cell line; (2) never placing flasks of different cultures of chemo-resistant cells in the biological safety cabinet at the same time; (3) using only tips and pipets with filters to prevent aerosol cross-contamination; (4) swabbing all pipettors with 70% propanol prior to use with each different cell line; (5) clearly labeled cell culture flasks and compound vials.