Content of 31 trace elements in thyroid malignant nodules and thyroid tissue adjacent to nodules investigated using neutron activation analysis and inductively coupled plasma mass spectrometry

Abstract

Thyroid malignant nodules (TMNs) are the most common endocrine cancer and the fifth most frequently occurring type of malignancies. Women are at particular risk for this thyroid disease The etiology and pathogenesis of TMNs must be considered as multifactorial. The present study was performed to clarify the role of some trace elements (TEs) in the etiology of these thyroid disorders. Thyroid tissue levels of silver (Ag), aluminum (Al), boron (B),, beryllium (Be), bismuth (Bi), cadmium (Cd), cerium (Ce), cobalt (Co), chromium (Cr), cesium (Cs), iron (Fe), gallium (Ga), mercury (Hg), lanthanum (La), lithium (Li), manganese (Mn), molybdenum (Mo), neodymium (Nd), nickel (Ni), lead (Pb), praseodymium (Pr), rubidium (Rb), antimony (Sb), scandium (Sc), selenium (Se), samarium (Sm), tin (Sn), thallium (Tl), uranium (U), yttrium (Y), and zinc (Zn) were prospectively evaluated in malignant tumor and thyroid tissue adjacent to tumor of 41 patients with TMNs. Measurements were performed using a combination of non-destructive instrumental neutron activation analysis and destructive method such as inductively coupled plasma mass spectrometry. Results of the study were additionally compared with previously obtained data for the same TEs in “normal” thyroid tissue. It was observed that main characteristics of TMNs in comparison with “normal” thyroid were significantly elevated levels of Ag, Al, B, Bi, Ce, Cr, Hg, Mn, Mo, Ni, Pb, Rb, Sm, and Tl. Furthermore, the TEs composition of thyroid tissue adjacent to tumor did not equal TEs contents of “normal” thyroid. Moreover, contents of such elements as Ag, Hg, and Se in adjacent tissue were higher than in tumor. Thus, from results obtained, it was possible to conclude that at least the excessive accumulation of Ag, Hg, and Se by thyroid tissue is likely to precede the TMNs origination and development. Elevated levels of Ag, Al, B, Bi, Ce, Cr, Hg, Mn, Mo, Ni, Pb, Rb, Sm, and Tl in nodular tissue could possibly be explored for differential diagnosis of benign and malignant thyroid nodules.