In contrast to the results in the HCT116 cell line, one in-vitro study concluded that combined inhibition of PI3K and ERK, induced by PIK3CA downregulation and PD0325901, respectively, was at least in part due to the induction of cell death (Wee et al, 2009), and an in-vivo study in mice with tumours carrying PI3K and Ras mutations demonstrated synergistic tumour regression with NVP-BEZ235 and AZD6244 (Engelman et al, 2008). This evidence concerns the gene PIK3CA and neoplasm.