PIK3CA and neoplasm: There are previous reports that the PI3K inhibitors GDC-0941 or NVP-BEZ235, or the MEK inhibitor PD 0325901, given as single agents caused significant decreases in [18F]-FLT uptake as early as 18, 24, 48 or 120 hours, associated with subsequent tumour growth inhibition in a variety of human tumour xenograft models [13], [14], [30], [39].