Characterizing Arsenic Speciation and Metallomic Profiles in Toenail Samples of Atlantic Canadians: A Matched Case-Control Study of Breast, Cervical, Prostate, Urinary, and Skin Cancers

Abstract

Chronic exposure to arsenic and metals has been associated with cancer risk. The research objectives were to 1) characterize the profiles of arsenic speciation and metallomes in the toenails of several cancer groups and healthy participants; 2) determine whether there is an association between the profiles of arsenic speciation and metallomes and cancers; while 3) adjusting for potential confounders. Total concentrations of metals and the levels of arsenic species were measured using Inductively Coupled Plasma-Mass Spectrometry (ICP-MS) and High Performance Liquid Chromatography (HPLC). The levels and profiles of arsenic speciation and metallomes were compared between cases and controls using MANOVA in adjusted and unadjusted analyses. The profiles of arsenic speciation and metallomes were significantly different between cancer cases and controls. Arsenic methylation capacity may be inversely associated with cancer risk. Toenail arsenic speciation and metallomes (e.g., zinc levels) may be an important biomarker for cancer risk. Further research is needed to use toenails as a prognostic measure of trace metal-induced cancer.