Bivariate analysis
In non-BC individuals there was significant (p < 0.01) correlation between CEBPG and eight of the 16 antioxidant or DNA repair genes, specifically XRCC1, ERCC5, GSTP1, SOD1, GPX1, ERCC1, CAT and ERCC2 (Table 4). In contrast, in BC individuals samples CEBPG was not correlated with any of the antioxidant or DNA repair genes. These relationships were not observed with any of the other transcription factors studied.
For XRCC1, ERCC5, GSTP1, and SOD1 the correlation with CEBPG was significantly lower in BC individuals compared to non-BC individuals and the difference was nearly significant for GPX1 (Fig. 1b). Scatter plots of the relationship between CEBPG and XRCC1 in non-BC individuals or BC individuals (Fig. 2a,b) are representative of the other four genes. Neither CEBPG, nor XRCC1, ERCC5, GSTP1, SOD1 or GPX1 was significantly correlated with age, gender, or smoking history in non-BC individuals, BC individuals, or the combined group.
In non-BC individuals, based on the r2 values from Pearson's correlation analysis, CEBPG accounts for much of the variance in expression of XRCC1 (69%), ERCC5 (62%), GSTP1 (55%), SOD1 (44%), and GPX1 (52%). E2F1 accounts for some of the remaining variance. For example, when samples from all 49 non-BC individuals and BC individuals were assessed as a single group, E2F1 was significantly correlated with ERCC5, GSTP1 and SOD1 (Table 4). Further, in non-BC individuals, E2F1 was correlated with GSTP1 (Fig. 1c) and the correlation was lower in BC individuals. However, the difference in correlation between non-BC individuals and BC individuals was not significant. None of the other transcription factors were correlated with XRCC1, ERCC5, GSTP1, SOD1, or GPX1 (Fig. 1a,d,e,f).