Figure 2. Cyclin E over expression increases DNA damage in normal breast cells.

(a) Bar diagram shows the expression level of γ H2AX, a marker of DNA double strand break, in terms of number of foci per cell as measured by immunofluorescence (IF) in MCF10A parental (P) or cyclin E over expressing cell clones {MCF10A CyE (B10) and MCF10A CyE (C3). The cells with 0–1 foci were considered with no DNA damage, 2–10 foci, were considered as moderate DNA damage and > 10 foci was considered as high levels of DNA damage. The values shown are mean + standard error obtained by counting more than 100 cells and was repeated 3 times. An asterisk (*) indicates the statistically significant differences from MCF10A (P) at p < 0.05. (b) Photomicrographs at 100× showing the nuclear accumulation of γH2AX by using IF technique where alexa-594 conjugated secondary anti-rabbit antibody was used to stain the γH2AX as red color and DAPI was used as a counter stain to visualize nuclei.