THE PLASMA CONCENTRATIONS OF ESSENTIAL TRACE ELEMENTS IN WOMEN WITH CANCER OF BREAST- OR CERVIX

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M.A. Jimoh¹, B.O. Popoola², G.O. Arinola³

1. Department of Radiation Oncology, University of Ibadan, Nigeria.
2. Faculty of Allied Health Sciences, Baze University, Abuja.
3. Department of Immunology, University of Ibadan, Nigeria.

Abstract

Background: Derangement of trace elements which could be due to systemic inflammation or oxidative stress is thought to be directly or indirectly involved in carcinogenesis. Aim is to evaluate plasma trace elements in female patients with cancer of breast- or cervix.

Material and Methods: This study was carried out in the Departments of Immunology and Radiation Oncology, University of Ibadan, Nigeria. Thirty (30) patients with cervical cancer, 30 patients with breast cancer and 30 age matched females without cancer as control were included in the study. Plasma separated from venous blood was analysed for the concentrations of zinc (Zn), iron (Fe), selenium (Se) and copper (Cu) using Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The sixty cancer patients were newly diagnosed and in a stable state.

Results: The mean plasma levels of Fe and Cu were significantly reduced in patients with breast cancer- or cervical cancer compared with control. The plasma concentrations of Fe, Cu, Zn and Se were significantly reduced in all patients having breast cancer and those in stage 2 compared with cervical cancer patients.

Conclusion: Available data further support a previous suggestion that blood levels of metal varies with different cancers. Thus, a need for differential supplementation based on cancer types when modulation of trace element levels becomes a therapeutic option.

Keywords: Cancers, Trace elements, Oxidative stress, Metal-binding-proteins, Therapeutic.

Introduction

Cancer is a complex disease characterised by unhindered multiplication and infiltration magnitude, which progresses from un-spread (Stage 1) to enlarged tumours entering into the adjacent tissues (as stage II or III) and other organs (Stage IV).¹ Each of these cancer stages or cancer type was reported to need personalised therapy or treatment intensity.² Besides genetic changes, tumour cells are denoted by sizeable changes in their metabolism influencing the demand for macronutrients and micronutrients.³ This, thus account for the potential roles of trace elements as diagnostic or prognostic markers of cancers.³ We aim to test the proposition of whether levels of the trace element selenium (Se), iron (Fe), copper (Cu) and zinc (Zn) are appropriate differentiators of two most prevalent female cancers (breast- and cervical- cancers).

Trace elements are involved in many biochemical processes supporting life. However, disruption of the balance between free radicals and antioxidants as a result of excesses or deficiencies of trace elements may cause a cellular and DNA injuries triggering carcinogenesis.⁴ Selenium based proteins (seleno protein P and plasma glutathione peroxidase), Cu-binding protein (caeruloplasmin), Zn-associated enzymes and Fe-transport proteins (ferritin and transferrin) are usually affected by conditions in cancer patients such as inflammation or hydration status.^5,6 These conditions are common to cancer patients. This therefore supports the basis for the present study. The involvement of Fe is not clear, though it differs with regard to tissue type and cancer progression. The changes in Fe concentrations were related to altered expression levels of Fe-regulatory proteins in breast cancer pathogenesis.⁷ Of the approximately 115 elements known, only 19 are absolutely required in the human diet called essential elements. Therefore, an essential element is one that is required for life and whose absence results in death.^3,4

An Indian study concluded that higher Cu serum level in breast cancer patients with respect to healthysubjects.⁸ Another study on serum Cu levels, found no significant difference between cancer patients and healthy females.⁹ In contrast, another study reported increased serum Cu levels in patients with benign breast cancer¹⁰. Reduced serum Zn levels in most patients with breast cancer have been linked to an aberrant expression of Zn transporters.¹¹ Low serum levels of Zn or Se was found in cervical cancer patients but no difference was reported in the serum level of Cu among cervical cancer patients compared to their cancer-free control.¹² In another study, low serum Zn, Se and Cu were reported in cervical cancer patients compared with healthy female control.^{3, 4} Variations in blood levels of trace elements was reported to be different based on differences in geographical location, gender, age, sample size, sample collection, tumour grade, cancer stages, cancer types, management strategy, race, analytical method, immune status and associated complications among other factors.^8-12 Based on above observations, the present study determined the plasma levels of Zn, Cu, Se and Fe in female Nigerians with breast- or cervical cancer. The strength of present study is the comparison of plasma trace elements in two female cancers.

MATERIALS AND METHODS
Following institutional ethical approval (UI/EC/23/0065), 5ml of blood was collected from newly diagnosed 30 patients with cervical cancer, 30 patients with breast cancer and 30 females without cancer as control subjects. Plasma separated from venous blood was analysed for the levels of Zn, Fe, Se and Cu by Inductively Coupled Plasma Optical Emission Spectrometry (ICP-OES). The mean and standard deviations of the data were presented as Tables and the difference between mean (± standard deviation) of the heavy metals between two groups was determined by Student t-test. p <0.05 was taken as significant. All participants on any form of supplementation were excluded. Also, all participants were female Nigerians of the same ethnicity. They reported no bleeding, no weight loss, were actively mobile, not on previous compulsory medications, not smoking and not drinking alcohol. Also, they were married, self employed and with at least primary school education. All cancer patients were in stage 2 without metastasis

RESULTS
Mean plasma concentrations of Fe and Cu were significantly decreased in patients with breast cancer or cervical cancer compared with controls. However, the mean plasma concentration of Zn or Se was not significantly different in patients with breast cancer or cervical cancer compared to control. But, mean plasma concentrations of Fe, Cu, Zn and Se were significantly decreased in patients having breast cancer compared to patients with cervical cancer. See Table1. As presented in Table 2, the plasma concentrations of Fe, Cu, Zn and Se were significantly reduced breast cancer patients compared to cervical cancer- patients at stage 2.