Human FANCC does not fully correct Fancc-deficient MEFs. (A) Survivals of transformed Fancc-deficient MEFS (MEF61) transduced with human FANCC (MEF61/hFANCC) or murine Fancc (MEF61/mFancc) that were treated with MMC for 5 days (mean ± SD from one representative experiment of 3 performed in triplicate). MEF61/hFANCC cells were significantly more sensitive than MEF61/mFancc or wild-type (MEF11.1) cells (P < .001; analysis of variance [ANOVA]). MEF61/hFANCC cells were significantly more resistant to MMC than MEF61 cells (P < .001; ANOVA). (B) The average number of breaks per metaphase of the displayed MEFs treated with indicated concentrations of MMC for 24 hours; 50 metaphases were scored per cell line. Quadriradial forms were counted as 2 breaks per cell. (C-D) Metaphase spreads of MEF61/hFANCC (C) or MEF61/mFancc (D) cells treated with 20 ng/mL MMC for 24 hours. Arrows indicate radials.