However, in-vivo combination studies exhibited the most impressive results, for example, synergistic regression was achieved using the PI3K inhibitor NVP-BEZ235 and the MEK inhibitor AZD6244 in mice with KRAS-G12D-induced lung tumours or EGFR mutant tumours (Engelman et al, 2008; Faber et al, 2009). The gene discussed is PIK3CA; the disease is neoplasm.