We further performed Gene Set Enrichment Analysis (GSEA) [34] and found that the differentially expressed genes between I P and I NP tumors were significantly overrepresented in signatures associated with ‘Hypoxia’, ‘EGF signaling’, ‘HRAS oncogenic’ and ‘Tumor angiogenesis’ (Additional file 1: Figure S2). The gene discussed is EGF; the disease is neoplasm.