The first studies exploring PON2 expression in solid cancers (tumor versus normal tissue) were carried out through cDNA microarray analysis and revealed enzyme upregulation in hepatocellular carcinoma and pancreatic adenocarcinoma, as well as in genitourinary neoplasms such as kidney, bladder, prostate, testicular, and endometrial cancers [29,30,31]. This evidence concerns the gene PON2 and urogenital neoplasm.