SUMO1 and gastric cancer: First, pseudogenes frequently display a tissue-specific expression profile in different organs, tissues, and even blood; for example, SUMO1P, a pseudogene of small ubiquitin like modifier 1 (SUMO1), is upregulated in gastric cancer (GC) tissues compared with benign gastric disease tissues 10, and expression of integrator complex subunit 6 pseudogene 1 (INTS6P1) in the plasma of hepatocellular carcinoma (HCC) patients is significantly decreased compared with the plasma of non-HCC patients 30.