It is of note that the herein observed ORs for the UGT1A6_19_G variant are in the range of the so far established common low-penetrance breast cancer susceptibility loci with ORs from 1.07 to 1.22 including polymorphisms in genes such as FGFR2 and TOX3. As of yet, this set of more than 20 known susceptibility loci accounts for about 8% of the heritability of breast cancer (Ghoussaini et al., 2012). Here, TOX3 is linked to breast cancer.