However, downregulation of PIK3CA upon C-KRAS-esiRNA treatment could not be observed in different lysates of these tumor treatment groups in Western blots, whereas PIK3CA expression was significantly downregulated in C-PIK3CA-esiRNA treated tumors (Fig 4Q, lower panel and Fig D-F in S2 File). The gene discussed is PIK3CA; the disease is neoplasm.