HLA-A and breast cancer: As shown in Fig. 2, higher proportions of homozygotes are found at single loci, especially HLA-A, compared to multiple loci: A (mean of 23.5 %) ≫ C (14.8 %) ≫ B (11.5 %) ≫ BC (7.78 %) ≫ AC (6.17 %) > AB (5.5 %) ≫ ABC (4.33 %) (p varying from 6e-13 to 0.005 according to pairwise Wilcoxon rank sum tests after Holm’s adjustment correction for multiple tests, except for AB and AC: corrected p value = 0.074).