To identify which among the differently expressed genes contribute to tumorigenesis, 558 tumorigenesis-related genes were classified into seven groupings corresponding to pathways in cancer: cell cycle, apoptosis, cytokine cytokine receptor interaction signaling pathway, MAPK signaling pathway, TGFβ signaling pathway, p53 signaling pathway and Esrb signaling pathway (Figure 4b, Supplementary Table S2 and Supplementary Figure S2). Here, ESR2 is linked to cancer.