- IGHMBP2 Thr671Ala polymorphism might be a modifier for the effects of cigarette smoking and PAH-DNA adducts to breast cancer risk. Shen, J., Beth Terry, M., Gammon, M.D., Gaudet, M.M., Teitelbaum, S.L., Eng, S.M., Sagiv, S.K., Neugut, A.I., Santella, R.M. Breast Cancer Res. Treat. (2006)