While that study found little independent effect of smoking on breast cancer incidence, another reanalysis of data from 10 studies found that smoking is related to breast cancer in women with a certain genotype, particularly N-acetyltransferase 2 (NAT2) slow acetylation genotype, which the authors note is present in at least one-half of Caucasian women [27]. Here, NAT2 is linked to breast carcinoma.