In our recent studies (Faratian et al., 2009b; Goltsov et al., 2011) we applied computational modelling methods, based on elucidation of control parameters within the PI3K/PTEN/Akt signalling module, to explore the mechanisms of therapeutic resistance to anti-ErbB2 inhibitors in human ovarian carcinoma cell lines. The gene discussed is PIK3CA; the disease is ovarian carcinoma.