Subjects enrolled in this study should not take or begin to take concomitant medications known to prolong the QT interval. If such medications are already being taken by the patient before study starts, a wash-out period of ≥ 7days is required prior to starting dasatinib. Medications known to prolong the QT interval and/or are generally accepted to have a risk of causing Torsades de Pointes ventricular arrhythmia are (see http://www.qtdrugs.org/medical-pros/drug-lists/drug-lists.htm):