ISG15 and neoplasm: In comparison, we found the ISG15 protein upregulated in nearly all of the tumours analysed in the study; it was overexpressed in 93% (26 out of 28) of Ta tumours, 100% (20 out of 20) of T1 tumours, and 98% (44 out of 45) of T2–T4 compared to the normal tissue samples.