Fig. 3.
Percentage of aberrant tumor cells and ploidy across the five breast cancer subtypes. Molecular subtypes used: LumA, Luminal A (n = 45); LumB, Luminal B (n = 10); ERBB2 (n = 12); Basal, Basal-like (n = 12); Normal, Normal-like (n = 8). (A) Distribution of percentage of aberrant tumor cells across the five subtypes. The box plots show the median (thick lines) and the lower and upper quartile (boxes). The whiskers reach up to the most extreme value within 1.5 times the interquartile range from the box. Whereas Luminal A carcinomas harbored the highest levels of aberrant tumor cells (P = 6.9 × 10−6, unpaired t test with unequal variance, testing for differences between the Luminal A subtype and all other carcinomas), tumors of the ERBB2 and Normal-like subtype displayed the lowest fraction of aberrant cells (P = 3.7 × 10−4 and P = 8.4 × 10−3, respectively). (B) Distribution of ploidy across the five subtypes. The vast majority of Luminal A tumors showed a ploidy close to 2n, with a smaller fraction showing a ploidy close to 4n. Carcinomas of the Luminal B subtype were approximately equally divided among 2n and 4n tumors, with two tumors being 3n. On average, the ERBB2 subgroup displayed the highest level of ploidy but also the broadest range. The Basal-like subgroup showed cases with a ploidy 1.6n–2n and cases of 2.8n–3.2n. Normal-like tumors showed a group of cases with ploidy close to 2n and a group of cases with ploidy above 3n.