For the SRBCT dataset, the fourth gene CAV1 in Additional file 1: Table S17, a tumor suppressor gene candidate that encodes protein Caveolin 1, has a linking degree of 73 in the PPI network, while the three proteins encoded by the top three genes CD99, MLLT11 and IGF2 in Additional file 1: Table S17 are 9, 0, and 16, respectively and have much lower CLD. This evidence concerns the gene IGF2 and neoplasm.