Zinc and copper levels in plasma, erythrocytes, and whole blood in cancer patients.

Zinc and copper levels in erythrocytes, plasma, and whole blood were determined in 35 cancer patients and compared with 24 normal individuals. A decrease in zinc was found in all three blood constituents of the cancer patients. The decrease was significant in plasma and whole blood and nonsignificant in erythrocytes. Copper levels in the cancer group showed a slight and nonsignificant increase in erythrocytes, plasma, and whole blood. The copper to zinc ratio revealed a significant increase only for plasma levels. Further investigations are indicated to determine whether these two elements could serve as indicators for diagnosis or prognosis in cancer patients.