This study aimed to validate previously associated major histocompatibility complex ( MHC ) variants as predictors of risk of liver injury by using a large , randomized , placebo-controlled trial of lapatinib in human epidermal growth factor receptor @-positive , early-stage breast cancer ( Tykerb Evaluation After Chemotherapy -LSB- TEACH -RSB- : Lapatinib Versus Placebo In Women With Early-Stage Breast Cancer ) .