PIK3CA and renal cell carcinoma: As for renal cell carcinoma pathway, 18 out of 70 gene members of the pathway were coordinately down-regulated in the HH group (Table 2; Additional file 7), which were featured by the genes encoding for several growth factors (TGFB2, TGFB3, VEGFA, PDGFB) and genes involved in cell survival and proliferation (GRB2-KRAS/NRAS-RAF1-MAPK3/ERK-JUN/AP1 leading to cell cycle progression and PIK3CA/PI3K leading to cell survival).