Intriguingly, we noticed the activity of the ubiquitin-mediated proteolysis pathway, as well as the expression of multiple ubiquitin-conjugating enzymes including UBE2S, UBE2E3 and UBE2C, were upregulated in tumor cells from solid samples (Fig. 1C; Additional file 2: Table S2). This evidence concerns the gene UBE2C and neoplasm.