Chlorine and Chromium Elements, Proteins of Oxidative Stress and Dna Repair Pathways Are Related to Tumor Aggressiveness and Prognosis of Patients With Oral Cancer

Abstract

BackgroundSquamous cell carcinoma (OCSCC), the most frequent cancer of the oral cavity, is extremely aggressive, the response to treatment is poor and markers for prognosis of disease are scarce. The comparison of chemical and histopathological data obtained from the analysis of excised tumor fragments with the demographic and clinical evolution data is an effective strategy scarcely explored in OCSCC studies. The aim was to analyse OCSCC tissues for trace elements and protein expression of enzymes related with oxidative stress and DNA repair that can be candidates as markers of tumor aggressiveness and prognosis. MethodsSeventy-eight tumor fragments from 78 OCSCC patients that had undergone ablative surgery were qualitatively analyzed by synchrotron micro-X-ray fluorescence (μ-XRF) for trace elements. Protein expression of superoxide dismutase (SOD-1) and thioredoxin (Trx) and DNA repair-related purinic/apyrimidinic endonuclease/redox factor-1 (Ref-1) and 8-oxoguanine glycosylase (OGG1/2) was performed by immunohistochemistry. Sociodemographic, clinical and hystopathological data were obtained from 4-year follow-up records. ResultsDisease relapse was higher in patients with chlorine and chromium presence and in those with tumors with strong OGG1/2 expression. Strong expression of SOD-1, Trx and Ref-1 was determinant of larger tumor. As expected, perineural, vascular invasions and alcohol consumption were markers of greater worse prognosis. ConclusionPresence of trace elements can be markers of disease prognosis. Strong expression of enzymes related with oxidative stress or DNA repair can be either harmful by stimulating tumor growth or beneficial by diminishing relapse rates. Interference on these players may bring novel strategies for the therapeutic management of OCSCC patients.