Plasma and tissue prolactin detection in colon carcinoma

Serum concentrations of prolactin, atrophic hormone produced by the pituita ry gland, have been shown to be raised in certain group of patients with ca ncer. Prolactin was detected in 0-20% of the colon cancer by immunohistoche mistry and in plasma in 6-53% of the patients. These conflicting results do not support the hypothesis of an ectopic prolactin production by colon car cinoma. The aim of this study was to confirm the reported incidence of hype rprolactinemia in colorectal cancer and to find further evidence for an ect opic prolactin production by the tumor. Thirty consecutive patients with co lon carcinoma were studied. Before surgery all the patients underwent blood sample collection to assay plasma prolactin levels. All patients underwent colectomy. All the neoplastic specimens were tested with antiprolactin ant ibody. In none of the patients were significantly high preoperative levels of plasma prolactin found. Prolactin immunostaining was not identified in a ny of the tumor specimens. We could not confirm previous reports of frequen t hyperprolactinemia in patients with cancer. This is the first report in w hich the incidence of both hyperprolactinemia and prolactin positive immuno staining was 0%. Our study was unable to demonstrate the synthesis of prola ctin by colorectal cancers. The tumor is unlikely to be the source of hormo ne production. Our results suggest that circulating prolactin levels cannot be used as prognostic marker in patients with colon cancer.