(C) Immunohistochemistry detection of PAR by ADP-ribose antibody in WT and Ews-/- cells after H2O2 treatment (1 mM, 20 minutes) and recovery from DNA damage. Right graph displays mean of intensities measured from 500 cells. Data represented as mean ±SEMs, significance determined by One-way ANOVA, ***P < 0.001. Scale bar indicate 20 μm. 