Serum zinc (Zn), copper (Cu), and the Cu/Zn ratio were evaluated in 84 patients with pulmonary lesions before surgery and in 100 healthy normal controls. There were 20 patients with benign and 64 with malignant lung tumors. Only the mean (kSD) Cu/Zn ratio was significantly higher in malignant tumors (2.24 * 0.78) than in benign tissue (1.63 3~ 0.33) (P < 0.001). In the normal group, the Cu/Zn ratio was significantly lower (1.43 k 0.29). Patients with advanced disease (Stage 111) had higher Cu/Zn ratio than patients in Stages I and I1 (2.65 k 0.86 versus 1.9 k 0.27) (P < 0.001). At a cutoff value of 1.72, Cu/Zn ratio had a sensitivity of 89%, specificity of 841, positive predictive value of 78%, and negative predictive value of 92% between controls and lung cancer patients. Between lung cancer patients and patients with benign pulmonary lesions the aforementioned values were 89%, 70%, 90%, and 70% respectively. A correlation between increasing Cu/Zn ratio and tumor extension and postoperative survival was observed. These findings suggest that Cu/Zn ratio may be used as a diagnostic test in lung cancer patients.
Cancer 63:726-730, 1989.
HE BIOLOGICAL ROLE of trace metals, especially of T copper and zinc, in different physiologic and pathologic conditions has been extensively investigated in recent years.',' Changes in serum copper and zinc levels have been found in lymphoproliferative disorder^,^-^ ovarian, breast, lung, and gastrointestinal cancer^,^-'^ sarcomas,'