- Evaluation of tamoxifen plus letrozole with assessment of pharmacokinetic interaction in postmenopausal women with metastatic breast cancer. Ingle, J.N., Suman, V.J., Johnson, P.A., Krook, J.E., Mailliard, J.A., Wheeler, R.H., Loprinzi, C.L., Perez, E.A., Jordan, V.C., Dowsett, M. Clin. Cancer Res. (1999)