The isoforms ENST00000306072.9 (ISG20-001) and ENST00000560741.5 (ISG20−009) showed the same structure consisting of 181 amino acids with an RNase_T domain as reported previously; isoforms ENST00000559876.1 (ISG20-006) with 155 amino acids and ENST00000379224.9 (ISG20-008) with 87 amino acids, both possessed a truncated RNase_T domain (Figure 5C), demonstrating the functional role of ISG20-001 and ISG20−009 in tumorigenesis and SARS-CoV-2 invasion inhibition in cancer patients. This evidence concerns the gene ISG20 and cancer.