Normal and FA(C) cells with similar amounts of MMC-induced cytogenetic abnormalities have similar G2/M accumulation. Cells were treated with control medium or medium containing MMC for 48 hours. JY cells were treated with 300 ng/mL of MMC, and PD149L and PD4L cells were treated with 40 ng/mL of MMC. After 48 hours the cells were harvested and DNA content measured by PI staining and flow cytometry. Cytogenetic analysis was performed on an aliquot of each sample. Results of a representative experiment are shown. The shaded area represents cells in S phase.