In subtype specific analysis, rs13387042 (per-allele adjusted OR = 1.36, 95% CI = 1.00-1.87) and rs4415084 (per-allele adjusted OR = 0.82, 95% CI = 0.66-1.00) showed slightly significant association with Luminal-A subtype; however, only rs13387042 was associated with ER-&PR-&HER2+ tumors (per-allele adjusted OR = 1.55, 95% CI = 1.00-2.40), and none of them were linked to Luminal-B and triple negative subtype.
The A allele of rs13387042 (2q35) was significantly associated with contralateral breast cancer in ER negative first tumors while the A allele of rs11235127 (near TMEM135) was significantly associated with contralateral breast cancer in ER positive first tumors.
Four of the eight loci identified in GWAS were associated with triple negative tumors (P ≤ 0.016): rs3803662 (16q12), rs889312 (5q11), rs3817198 (11p15) and rs13387042 (2q35); however, only two of them (16q12 and 2q35) were associated with tumors with the core basal phenotype (P ≤ 0.002).