Melphalan-resistant cells have a more rapid kinetics of γH2AX foci formation than sensitive cells.

<p>(A) The number of γ-H2AX foci per cell nucleus (N>13) was manually quantified for each time point and the experiment was performed in triplicate. Corresponding standard deviation bars are indicated. P<0.01 at all time points as calculated using 2-sample t-test with equal variance. (B) Representative confocal images of the cells at different time points subsequent to Melphalan treatment. Foci formation was monitored using γH2AX polyclonal antibody (red) and due to the significant fraction of NFkB protein present in the cytoplasm of these cells, NFkB p65 mouse monoclonal antibody was used as control for cytoplasmic staining (green).