A comprehensive analysis of common genetic variation in prolactin (PRL) and PRL receptor (PRLR) genes in relation to plasma prolactin levels and breast cancer risk: the multiethnic cohort. - Lee SA; Haiman CA; Burtt NP; Pooler LC; Cheng I; Kolonel LN; Pike MC; Altshuler D; Hirschhorn JN; Henderson BE; Stram DO (BMC medical genetics, 2007)