Zinc, copper, and parenteral nutrition in cancer. A review

Study of Serum Zinc and Copper Levels and Tumor Pathology: A Pilot Study in People Affected with Head and Neck Cancers

This study aimed to determine understanding the role of serum copper, zinc and copper/zinc ratio with tumor staging in people newly diagnosed to be affected with Head and Neck cancer and by comparing with age matched health individuals devoid of any orodental maladies. The study included patients confirmed to be affected with HN cancer with histological diagnosis of Head and Neck cancer (60) and age matched healthy volunteers (N = 23). The demographic details like age, domicile, menopausal status and pathological details (like tumor stage, number of lymph node involvement, tumor size) were collected from the patient's hospital data file. The serum levels of zinc and copper assayed as per standard procedures and the zinc/copper was calculated for the cancer patients and controls. The data were subjected to unpaired "t" test and ANOVA with Bonferroni's multiple comparisons. The association between zinc and copper levels with pathological details between the variables was ascertained using the Pearson correlation coefficient(r). A statistical value of p < 0.05 was considered to be significant in agreeance to the accepted norms. Results: This result of the study indicates that when compared to the healthy individuals, the serum levels of copper, and zinc, and copper/zinc ratio were high in patients with H&N cancer. Also when compared with controls, the levels of zinc decreased, while that of copper and copper/zinc ratio increased in people affected with H&N cancer (p = 0.017 to 0.0001) and with the stage of the tumor (p = 0.03 to 0.001). The results of the study suggest that levels of serum zinc were significantly lower and that of copper higher in H&N cancer patients than that in controls and also that it was dependent on the tumor stage. When analyzed cumulatively the results hint that zinc and copper, due to their role in free radical generation and prevention have an important role in cancer progression and possible prevention by judicious intervention.

Technical aspects of trace element supplementation

Routine supplementation of total parenteral nutrition mixtures with the readily available single or combination trace elements products is becoming more widespread. As more is learned about deficiency syndromes and monitoring techniques, so too must we understand more about the physicochemical interactions between individual trace elements and other nutrients, that could ultimately affect bioavailability. Expert pharmaceutical assessment of these complex reactions, that have been demonstrated to occur in solution, becomes increasingly important in order to optimize the efficacy of micronutrient therapy.

Serum ceruloplasmin and the risk of cancer in Finland

The relationship between serum ceruloplasmin level and cancer incidence was investigated in a case-control study nested within a longitudinal study of 39,268 Finns participating in the Social Insurance Institution's Mobile Clinic Health Examination Survey carried out in 1968-1972. During a median follow-up of 8 years, 766 cancer cases were identified. Ceruloplasmin levels were determined from stored serum samples collected at the baseline from these cancer cases and from two matched controls per case. The overall incidence of cancer was positively associated with serum ceruloplasmin level. The association was strongest for lung cancer and other cancers related to smoking and, consequently, in males. The smoking-adjusted relative risk of lung cancer among men was 4.3 (95% confidence interval (CI) = 1.8-10.6) in the highest quintile of serum ceruloplasmin as compared with that in the lowest quintile. The corresponding relative risks for cancers related to smoking combined, and for cancers not related to smoking were 3.9 (CI = 1.9-8.4) and 0.9 (CI = 0.6-1.5), respectively. The elevated risk of lung cancer at high concentrations of serum ceruloplasmin persisted after further adjustment for several potential confounding factors such as serum levels of vitamins A and E and selenium. The risk was stronger during the first 6 years of follow-up than later, and strongest during the first 2 years. The most likely explanation of the present results thus is that high serum ceruloplasmin levels in lung cancer are mainly due to occult cancer.

Zinc and copper in breast cancer. A joint study in northern Italy and southern France

The relationship between breast cancer and two trace elements, zinc (Zn) and copper (Cu), was investigated by means of an hospital based case-control study at Milan (Italy) and Montpellier (France). Variables concerning dietary intake of Zn and Cu (in Milan) and their blood levels (both in Milan and Montpellier) were measured. Dietary intake, evaluated through a questionnaire of the dietary history type, and blood levels of Zn and Cu were measured in 261 cases and 261 controls. Cu blood level showed a contradictory tendency in the two samples (higher in controls in Milan, higher in cases in Montpellier), which tended to lessen after adjustment for related variables. No odds ratios (OR) in the different quantiles, nor X2 for trend reached statistical significance. A sharp difference was evidenced on the opposite with regard to Zn blood values in cases and controls. In both samples Zn mean values are significantly higher in cases than in controls, and the difference remains significant in the two samples even after adjustment for related variables. The pooled OR computed from the two samples, after adjustment for known risk factors and related variables, reaches in the fourth quartile a value of 9.5 (CI: 4.9-18.2). Dietary intake of the two minerals (measured only in Milan sample) showed no difference between cases and controls, but a stronger relationship between dietary and blood Zn was evidenced in cases with respect to controls. The authors suggest that the higher Zn level in cases might be related with an higher incorporation of Zn in cancer cases and that the same mineral might play a possible role in tumor growth promotion.

Leucocyte zinc in non-Hodgkin's lymphoma and Hodgkin's disease

Zinc status and the effect of zinc supplementation were assessed in groups of patients with non-Hodgkin's lymphoma and Hodgkin's disease; patients were either untreated or in remission. In the patients in remission, plasma zinc was normal; and whereas 30% of untreated patients had low plasma zinc, the group as a whole did not differ from normal. For mononuclear cell zinc, the range of values in the disease group was far wider than in controls, but there was no significant difference between the means of the groups. Granulocyte zinc was significantly lower in both the groups of patients in remission from non-Hodgkin's lymphoma and Hodgkin's disease compared with the control group. Significant increases were found in the plasma copper, ceruloplasmin, and the copper-to-zinc ratio in several of the patient groups. Plasma zinc increased by 23% with zinc supplementation (50 mg elemental Zn/day), but there was no effect on mononuclear cell or granulocyte zinc. Apart from granulocyte zinc, there is little evidence of zinc deficiency in non-Hodgkin's lymphoma or Hodgkin's disease. However, the presence of depleted granulocyte zinc levels could modify the immune function of this cell population.

Host zinc metabolism and the Ehrlich ascites tumour. Zinc redistribution during tumour-related stress

Zinc redistribution between plasma and liver has been examined in mice injected with Ehrlich-ascites-tumour cells. Within 24 h of injection plasma Zn levels decrease and Zn appears in newly synthesized liver metallothionein. This response is dependent upon the number of tumour cells injected into the host. Uptake of Zn into liver and its specific accumulation in a Zn-binding protein, identified as metallothionein, continues for a number of days and reaches a plateau as tumour growth ceases. Over this time period, plasma copper rises. This redistribution also occurs in mice pretreated with cadmium in their drinking water for 1 month at levels of 20, 50, and 100 micrograms/ml. However, in each case there is a lag of 3 days before Zn increases in the livers of these animals which already contain substantial amounts of Cd/Zn-metallothionein. When Ehrlich cells are injected into mice previously placed on a Zn-deficient diet for several days, plasma Zn is already low and no net uptake of Zn into liver metallothionein is apparent. Finally, it is shown that ascites fluid can itself stimulate a transient shift of host of Zn into liver. Heat-inactivated fluid loses this property. It is suggested that, in the peritoneum, tumour cells initiate a stress response mediated by an ascites-fluid factor.

Micronutrient requirements of cancer patients

Several major factors may influence the micronutrient requirements of the patient with cancer. These factors include the metabolic state of the malignancy and its effects on host metabolism, the catabolic effects of antineoplastic therapy, and other physiologic stresses commonly associated with the treatment of cancer, i.e., surgery, fever and infection. Although the nutritional importance of vitamins, minerals and trace elements is recognized, the optimal daily dose that will preserve lean body mass without enhancing tumor growth, is not known. Recommended Dietary Allowances (RDAs), where established, are based on populations with nonmalignant diseases. However, supplementation with vitamins, minerals, and certain trace elements is recommended for the cancer patient who requires prolonged parenteral support, since clinically relevant deficiency states have been described. The effect of malignancy on the metabolism of several of these micronutrients (iron, ascorbic acid, alpha tocopherol, selenium, zinc, copper) is discussed.

Hypocupremia in patients receiving total parenteral nutrition

Although hypocupremia is a well-known consequence of long-term total parenteral nutrition (TPN), its incidence as well as the duration of TPN necessary to induce it are still unsettled. The purpose of this study is to review the changes in serum copper level in 25 patients receiving TPN for a period longer than 2 wk (mean duration 6 wk) at the Istituto Nazionale Tumori of Milan and to evaluate the possible relationship of cupremia with the basic disease. Main indications for TPN included enterocutaneous fistulas (11 patients), cancer cachexia (10 patients), radiation enteropathy (two patients), and severe postoperative stricture following esophagogastric resection (two patients). Mean value of serum copper at the beginning of the study was 143 micrograms/100 ml (normal value 65-165 micrograms/100 ml), and the regression analysis showed a mean fall of 5.64 micrograms/100 ml/wk. Hypocupremia occurred in four patients (three with intestinal fistulas and one with radiation obstructive enteritis) at 5th, 6th, 9th, and 6th wk of TPN, respectively. No patient with cancer cachexia developed hypocupremia. No patient with hypocupremia had clinical evidence of a copper deficiency syndrome. We conclude that 1) hypocupremia does not occur within the first month of TPN; 2) its incidence is about 16% in patients intravenously fed for period longer than 2 wk; 3) it is more frequent in patients with enterocutaneous fistulas, whereas it never occurs in patients with cancer cachexia, and 4) it is not necessarily associated to a clinicometabolic syndrome of copper deficiency. Finally, the "nutritional" meaning of serum copper should be questioned in cancer patients since it could represent a "tumor marker."

Tumor-host zinc metabolism the central role of metallothionein

Features of tumor and host zinc metabolism are described. Emphasis is placed on tumor-host interactions. Using the model of the Ehrlich ascites tumor in mice, one clear site of modulation of cellular zinc by the amount of nutrient zinc available in the host is a zinc-binding protein with the properties of metallothionein. The selective depletion of zinc from this protein is correlated with the loss of cell proliferation by tumors injected into zinc-deficient animals. The properties of isolated metallothionein are consistent with a role for it as a reactive pool of intracellular zinc which can be donated to apozinc proteins and other structures. The presence of the Ehrlich tumor in mice also perturbs their distribution of zinc: zinc leaves the plasma and is accumulated by liver in the form of newly synthesized zinc metallothionein. During host zinc deficiency, this redistribution is not observed. This may be caused not only by a lack of mobile plasma zinc, but also by an inhibition of the initiation of this host response at the site of the tumor in the peritoneum.