Detection of Toxic Metals in Human Biological Samples of Cancer Patients

Abstract

Cancer is known to be a process consisting of several steps and stages including initiation, promotion, progression and metastasis. Chemical carcinogens such as trace metals can cause variations in any of these processes to induce their carcinogenic effect. These elements perform specific and important functions in several metabolic processes of cells and tissues. Deficiency of trace elements or excess is implicated in the development of some cancers and stimulates the growth of tumors. The main purpose of this study is to evaluate the concentration of trace elements Cu, Zn, Cd, Ni and Pb in non-invasive biomarker hair, nails and blood samples. These samples were collected from cancer patients from different hospitals of Karachi. In hair, nails and blood we have determined the concentration of Copper (Cu), Zinc (Zn), Cadmium (Cd), Nickel (Ni) and Lead (Pb) in healthy and cancerous individuals. However, some drastic change was observed in cancerous and healthy samples of hairs, nails and blood. The results of healthy hairs and nails revealed high concentration of cadmium (Cd) as compare to cancerous hairs and nails samples. While the concentration of Copper (Cu), Zinc (Zn), Nickel (Ni) and Lead (Pb) were found high in cancerous patients. A comparative study in blood of cancerous and healthy individuals showed that the mean concentration were higher in cancer patients related to the healthy except zinc which showed higher concentration in healthy. For the analysis of toxic metals in human biological samples, Flame Atomic Absorption Spectrophotometer (FAAS PE-AAnalyst-700) and Graphite Furnace Atomic Absorption Spectrophotometer (GFAAS) were used. Statistical parameters were applied on the data to determine the significance of mean values between different and each sample. It was concluded that the mean concentration of Zn, Cu and Ni were within the range of WHO guideline except the concentration of Pb and Cd which were found higher than WHO recommended values. In cancerous hair and nails samples, all the metals were observed within the acceptable range with reference to WHO guideline. Anodic stripping voltammetry (CHI 760D) was used to determine concentration of Cu and Pb in cancerous and healthy human serum in presence of acetate buffer (pH 5.2, 0.1M) as supporting electrolyte at 30±1 0C by using Glassy carbon as a working electrode, Pt wire as counter and Ag/AgCl as reference electrode via standard addition method. This is a very sensitive and rapid technique. The level of concentration of copper and lead were determined by calibration curve. The sensitivity of proposed method was observed by regression statistic through LOD (133.9, 39.0 µM) and LOQ (44.1, 13.0 µM) with the correlation coefficient (R2) 0.903, 0.957 for

copper and lead respectively. Heavy metals may have prognostic importance in complex diseases such as cancer and this fact may be associated to environmental or occupational factors. The significance of this technique is that it required minimum time, least quantity of sample with higher sensitivity. The techniques used for this study are very fast and efficient. This quantitative study is helpful to know the impact of toxic metals on our environment and human health. It is very necessary to investigate the concentration of toxic metals in biological samples because now a day’s these metals produce many disorders and diseases like cancer.