PIK3CA and neoplasm: Interestingly, two mice in the NVP-BEZ235 treatment cohort experienced incomplete responses with partial tumor regression and progression, respectively (T2 and T4, Figure S3A, B), and in each case inhibition of PI3K (AKTSER473/308) and mTOR (RPS6SER240/244) was incomplete, with only partial reduction in MYCN levels (M2 and M4, Figure 6D).