Early breast cancer, diet, and plasma copper fractions

In a study of diet and early breast cancer, blood plasma copper has been analyzed by Proton Induced X-ray Emission analysis as both total copper (P-Cu) and that ultrafiltrable from plasma (P-edu-Cu) through membranes with a cut-off at molecular mass 10,000 after equilibration with disodium ethylene diamine tetraacetic acid (EDTA) at 4 degrees C. Ceruloplasmin (P-cer) was also measured using nephelometry of anticeruloplasmin monoclonal antibody-ceruloplasmin complexes. Dietary copper intake per day (D-Cu) was assessed over a five-day dietary record period and calculated from dietary components using a computer program. P-edu-Cu correlated significantly with both D-Cu and ceruloplasmin while P-Cu correlated only with ceruloplasmin. Further, ceruloplasmin did not significantly correlate to D-Cu. Hence, P-edu-Cu better reflects copper status than do P-cer or P-Cu as it relates to both the major copper enzyme in plasma and to daily copper intake. This may be important in drawing conclusions about the significance of copper in disease states where copper fractions other than ceruloplasmin may be most important owing, for example, to oxidative properties. Categorization as cancer or normal, by copper parameters (D-Cu, P-edu-Cu, P-Cu, P-cer), was studied in multiple correlation. In particular, the ratio P-cer/P-Cu and the ratio P-edu-Cu/D-Cu were significantly related to disease. Irrespective of age (pre- and post-menopausal), highly significant differences between normals and early stage breast cancer patients were seen with p < 0.0001 to p < 0.01. The precise role played by plasma and dietary copper fractions deserves continued attention in view of the present and earlier results in cancer studies.