Log-transformed levels of total DNA damage (A) and DNA strand breakage (B) expressed as logarithmically-transformed relative amount of DNA in respective comet tails in whole blood leukocytes of healthy controls (solid) and BrC cases (stripes) carrying the respective wild-type (<i>wt-</i>; dark columns) or rare-allele containing (<i>var</i>-; light columns) genotypes.

<p>Only dominant genetic model was assumed. Identification of genotypes as <i>wild-type</i> or rare-allele containing (i.e. heterozygotic and <i>rare</i> homozygotes) with reference to <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110696#pone-0110696-t003" target="_blank">Table 3</a>, in which individual genotypes for each SNP are ordered accordingly. Data are presented as means (columns) ± SD (error bars). Logarithmical transformation was employed in order to normalize the distribution of raw comet assay data for the purpose of ANOVA/ANCOVA analysis. Total DNA damage data for <i>wt</i>-controls, <i>var</i>-controls, <i>wt-</i>cases and <i>var</i>-cases, respectively (log-%): <b>rs302874:</b> 0.56±0.17, 0.47±0.24, 0.57±0.16, 0.55±0.19; <b>rs12946522:</b> 0.49±0.23, 0.50±0.25, 0.57±0.17, 0.53±0.19; <b>rs302873:</b> 0.56±0.17, 0.47±0.24, 0.57±0.16, 0.55±0.19; <b>rs16943176:</b> 0.50±0.23, 0.50±0.25, 0.57±0.18, 0.53±0.18; <b>rs12946397:</b> 0.50±0.23, 0.50±0.25, 0.57±0.18, 0.53±0.18; <b>rs17222691:</b> 0.50±0.23, 0.50±0.25, 0.57±0.18, 0.54±0.17; <b>rs28363302:</b> 0.49±0.21, 0.54±0.38, 0.55±0.18, 0.64±0.14. DNA strand breakage data <i>wt</i>-controls, <i>var</i>-controls, <i>wt-</i>cases and <i>var</i>-cases: <b>rs302874:</b> 0.17±0.25, 0.15±0.18, 0.35±0.19, 0.26±0.18; <b>rs12946522:</b> 0.15±0.20, 0.21±0.21, 0.29±0.19, 0.32±0.18; <b>rs302873:</b> 0.17±0.25, 0.15±0.18, 0.35±0.19, 0.27±0.18; <b>rs16943176:</b> 0.14±0.20, 0.21±0.21, 0.29±0.19, 0.32±0.18; <b>rs12946397:</b> 0.14±0.20, 0.21±0.21, 0.29±0.19, 0.31±0.18; <b>rs17222691:</b> 0.14±0.20, 0.21±0.21, 0.29±0.19, 0.32±0.18; <b>rs28363302:</b> 0.17±0.20, 0.06±0.20, 0.28±0.19, 0.40±0.16. See <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110696#pone-0110696-t005" target="_blank">Table 5</a> for the summary of statistical analysis.</p

Levels of TBARS (dark columns), DNA strand breakage (grey columns) and total DNA damage (white columns) determined in whole blood samples from BrC cases and healthy control females.

<p>Data presented as medians (columns) and interquartile ranges (whiskers). Levels of TBARS among BrC cases (n = 132) vs. control females (n = 189): 2.6 [2.1–3.3] μM vs. 2.3 [1.8–2.7] μM, p<0.0001, Mann-Whitney <i>U</i> test (***). Levels of DNA strand breakage and total DNA damage were assessed in the whole group of BrC cases and tested for differences against a subset of 40 control subjects randomly selected from the whole control group by means of the age-stratified randomization (<i>see <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110696#s2" target="_blank">Materials and Methods</a></i>). DNA strand breakage: BrC cases vs. controls: 2.0 [1.5–2.7] %DNA in comet tail vs. 1.6 [1.1–2.1] %DNA in comet tail, p<0.001, Mann-Whitney <i>U</i> test (**). Total DNA damage: BrC cases vs. controls: 3.5 [2.9–4.6] %DNA in comet tail vs. 3.5 [2.4–4.6] %DNA in comet tail, <i>NS</i>. The age distribution in the control subset was verified to match with the one in the whole control group (<i>see </i><a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110696#pone-0110696-t001" target="_blank"><i>Table 1</i></a>). The distribution of TBARS in the randomized subset of 40 controls did not differ significantly from the one observed in the whole control group (1.7 [1.5–2.1] μM vs. 2.3 [1.8–2.7] μM, <i>NS</i>) but differed significantly from the one in the BrC group (1.7 [1.5–2.1] μM vs. 2.6 [2.1–3.3] μM, p<0.001, Kruskal-Wallis <i>H</i>-test post-hoc analysis).</p

Observed frequencies of genotypes and haplotypes reconstructed based on SNPs located within the LD block identified in <i>RAD51C</i>, together with respective odds ratios (OR) and corresponding 95% confidence intervals in BrC cases and healthy controls.

<p>Observed frequencies of genotypes and haplotypes reconstructed based on SNPs located within the LD block identified in <i>RAD51C</i>, together with respective odds ratios (OR) and corresponding 95% confidence intervals in BrC cases and healthy controls.</p

Summary of the analysis of effect of <i>RAD51C</i> SNPs and BrC on DNA damage.

<p>Summary of the analysis of effect of <i>RAD51C</i> SNPs and BrC on DNA damage.</p

The map of LD between seven analyzed SNPs in non-coding regions of <i>RAD51C</i>.

<p>The values in the map are the normalized measures of allelic association |D’| (<b>A</b>) and correlation coefficients (r²) (<b>B</b>) calculated for each pair of SNPs (both provided as percentages). The color scheme represent the corresponding confidence bounds for a given pair of SNPs: black – strong evidence of LD; grey – inconclusive; white – strong evidence of recombination <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110696#pone.0110696-Barrett1" target="_blank">[37]</a>. Solid line indicates the identified 1 kb-long LD block, within which common and rare haplotypes were reconstructed, the frequency of which is provided in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110696#pone-0110696-t003" target="_blank">Table 3</a>. Algorithm employed for LD block identification is described in the <a href="http://www.plosone.org/article/info:doi/10.1371/journal.pone.0110696#s2" target="_blank"><i>Material and Methods</i></a> section.</p

Characteristics of the groups of subjects involved in the study.

<p>Characteristics of the groups of subjects involved in the study.</p

Effect of <i>RAD51C</i> SNPs and BrC on blood plasma log-levels of TBARS.

<p>Effect of <i>RAD51C</i> SNPs and BrC on blood plasma log-levels of TBARS.</p

Resume of <i>RAD51C</i> SNPs analyzed in the study.

<p>Resume of <i>RAD51C</i> SNPs analyzed in the study.</p

The effect of <i>RAD51C</i> SNPs and BrC on ratio of oxidatively generated DNA damage to DNA strand breakage.

<p>The effect of <i>RAD51C</i> SNPs and BrC on ratio of oxidatively generated DNA damage to DNA strand breakage.</p