In 2 cases of UCEC, 1 case of SKCM, 1 case of LUSC, and 1 case of pancreatic adenocarcinoma (PAAD), a nonsense or missense mutation was detected in the glycogenin-2-3 domain of HAS1 at amino acid position 284, where arginine (R) was replaced by a stop codon (*), glutamine (Q), or proline (P), resulting in a premature termination or alteration of the amino acid sequence. Here, GYG1 is linked to pancreatic adenocarcinoma.