Multivariate Investigation of Toxic and Essential Metals in the Serum from Various Types and Stages of Colorectal Cancer Patients

Abstract

Colorectal cancer (CRC) is currently one of the most frequent malignant neoplasms, ranking 3rd in incidence and 2nd in mortality both in the USA and across the world. The pathogenesis of CRC is a complex interaction between genetic susceptibility and environmental factors such as exposure to metals. Therefore, the present study was intended to assess the imbalances in the concentrations of selected essential/toxic elements (Pb, Cr, Fe, Zn, As, Cd, Cu, Se, Ni, and Hg) in the serum of newly diagnosed colorectal carcinoma patients (n = 165) in comparison with counterpart controls (n = 151) by atomic absorption spectrometry after wet-acid digestion method. Serum carcinoembryonic antigen (CEA) of the CRC patients was determined using immunoradiometric method. Body mass index (BMI) which is an established risk factor for CRC was also calculated for patients and healthy controls. Conversely, average Ni (2.721 μg/g), Cd (0.563 μg/g), As (0.539 μg/g), and Pb (1.273 μg/g) levels were significantly elevated in the serum of CRC patients compared to the healthy donors, while the average Se (7.052 μg/g), Fe (15.67 μg/g), Cu (2.033 μg/g), and Zn (8.059 μg/g) concentrations were elevated in controls. The correlation coefficients between the elements in the cancerous patients demonstrated significantly dissimilar communal relationships compared with the healthy subjects. Significant differences in the elemental levels were also showed for CRC types (primary colorectal lymphoma, gastrointestinal stromal tumor, and adenocarcinoma) and CRC stages (stage-I, stage-II, stage-III, and stage-IV) among the patients. Majority of the elements demonstrated perceptible disparities in their levels based on dietary, habitat, gender, and smoking habits of the malignant patients and healthy subjects. Multivariate methods revealed noticeably divergent apportionment among the toxic/essential elements in the cancerous patients than the healthy counterparts. Overall, the study showed significantly divergent distribution and associations of the essential and toxic elemental levels in the serum of the CRC patients in comparison with the healthy donors.

Keywords: Colorectal cancer; Metals; Pakistan; Serum; Statistical analysis; Types/stages.