Pharmacogenetic characterization of BRAF knockout cell clones. Cells were incubated with different chemotherapeutic agents. On day 7 the cells were lyzed and proliferation was determined by SYBR green I staining of DNA. A-E: No differences in response were observed between BRAF-mutant and wild-type clones with mitomycin C, oxaliplatin, paclitaxel, etoposide, or 5-fluorouracil. F: EGFR expression was verified in all cell clones by Western blotting. No different proliferation behavior between the corresponding cell clones was observed upon treatment with monoclonal EGFR antibody cetuximab in concentrations up to 800 mg/L. As a positive control, the colorectal cancer cell line Lim1215 was used.