Mammographic density is positively associated with several other risk factors and biomarkers, including breast intraepithelial neoplasia [13], serum insulin-like growth factor-I and growth hormones in premenopausal women [14], serum prolactin and combined estrogen plus progestin HRT in postmenopausal women [15,16], and family history of breast cancer [17]. This evidence concerns the gene IGF1 and breast cancer.