CYP19A1 and breast cancer: In their 2009 study of 58 postmenopausal women [29 breast cancer patients on aromatase inhibitors (AI) versus 29 controls], Taichman et al. [22] found that AI users had significantly worse periodontal health, including higher levels of osteocalcin and TNF, attachment loss (P < 0.01), and bleeding on probing (P = 0.02).