However, when accounting for potential effect modification, rs23051560 (Ala394Thr) in the largest circadian gene, Neuronal PAS domain protein 2 (NPAS2) was most strongly associated with breast cancer risk (nominal test for interaction p-value = 0.0005; 10,000-permutation-based main-effects p-value among women with < 24 months of shift-work = 0.003).
A single nucleotide polymorphism (SNP) rs2305160 in Neuronal PAS domain protein 2 (NPAS2), the largest circadian gene, was identified as a breast cancer susceptibility locus.
We found that women with the heterozygous Ala394Thr genotype were significantly associated with breast cancer risk compared to those with the common homozygous Ala394Ala (OR = 0.61, 0.46-0.81, P = 0.001).