Selenium blood levels are lower in patients with stomach, colon or rectum cancer.
"Selenium concentrations in the full blood and erythrocyte and plasma GSH-Px activity were determined in patients with cancer of the stomach, colon and rectum. The results were compared with those in the group of healthy subjects. Blood samples were collected into heparinized tubes prior to surgery. Selenium concentrations in the full blood and plasma were lower (75.5 ng/mL and 56.2 ng/ml, respectively) in patients with the cancer of the stomach than healthy subjects (99.5 ng/ml and 78.5 ng/mL, respectively; p < 0.0001). Concentration of this element in both full blood and plasma was also lower in patients with cancer of the colon and rectum (77.7 ng/mL and 61.0 ng/ml, respectively; p < 0.0001). Erythrocyte and plasma GSH-Px activity was also significantly lower (p < 0.001) in patients with cancer of the stomach than in healthy subjects, and amounted to 13.6 U/g Hb and 188 U/L, respectively. Activity of this enzyme in patients with cancer involving lower segment of GI tract amounted to 15.9 U/g Hb and 190 U/L of plasma, and was significantly lower (p < 0.001) than in normal subjects in whom it amounted to 21.0 U/g Hb and 256 U/L of plasma.."
(Pawlowicz Z; Zachara BA; Trafikowska U; Nowicki A. [Low levels of selenium and activity of glutathione peroxidase in blood of patients with gastrointestinal neoplasms]. Polski Tygodnik Lekarski, 1993 Jun 21-28, 48(25-26):554-6)
"To investigate the relationship between serum Se contents and the risk of cancer, 4857 serum samples were obtained from cancerous (2730) and non-cancerous patients (2127). In this cohort the incidence of cancer in the non-cancerous patients was followed for the subsequent 3 years. The serum Se level of non-cancerous patients who later developed cancer during the 3 years was determined and compared with that of the non-cancerous patients. A high incidence of cancer was observed in the lower serum Se patients of the non-cancerous group. ."
(Ujiie S; Itoh Y; Kikuchi H. [Serum selenium contents and the risk of cancer]. Gan To Kagaku Ryoho Japanese Journal of Cancer and Chemotherapy, 1998 Oct, 25(12):1891-7)
See also: Selenium Biochemistry and Cancer: A Review of the Literature by Fraqnk M. Painter, D.C.