HPD and pancreatic ductal adenocarcinoma: Among them, HPDL, 4-hydroxyphenylpyruvate dioxygenase-like protein, a previously uncharacterized protein, localized in mitochondria, where it may function as 4-hydroxyphenylpyruvate dioxygenase, which was recently reported to be positively associated with the development of pancreatic ductal adenocarcinoma (PDAC) (36), AML (37), and breast cancer (38).