BCL2 and Thrombocytopenia: ABT-737 treatment induced thrombocytopenia, a marker of ABT-737 pharmacodynamics in vivo, confirming on-target action in these experiments (Supplementary Fig. 6).29 Although the 5-day combination treatment did not eradicate the entire tumor, the enhancement in cell death indicates that BCL2 family proteins contribute to the adaptive survival response to lapatinib.