PPARGC1A and neoplasm: Emerging evidence exhibits that CDC4 has been confirmed as a tumour suppressor due to the wide involvements in degradation of diverse proteins associated with oncogenic developments, including cyclin E, c-Myc, c-Myb, c-Jun, Notch, MCL1, MED13/13L, PGC-1α, C/EBPα, TGIF1 and KLF5 [22-27].