Increased Expression of Superoxide Dismutase 2 Is an Indicator of Worse Prognosis of Oropharyngeal Cancer

TL;DR

High levels of SOD2 in oropharyngeal cancer are linked to worse survival outcomes, regardless of HPV status.

Contribution

Identifies SOD2 as a novel prognostic marker for oropharyngeal cancer.

Findings

High SOD2 expression is a significant poor prognostic factor for overall survival in OPC.

SOD2 expression predicts worse outcomes regardless of HPV status.

No significant associations were found between SOD1/SOD2 and tumor stage or lymph node metastasis.

Abstract

Human papillomavirus (HPV) is a known risk factor for oropharyngeal cancer (OPC), with distinct HPV-positive and HPV-negative subtypes. Reactive oxygen species have been implicated in the carcinogenesis of several malignancies. Superoxide dismutase 2 (SOD2), a mitochondrial enzyme, is highly influenced by oxidative stress. This study investigated whether SOD1 and SOD2 expression in OPC affects primary tumor progression, lymph node metastasis, stage, and overall survival (OS). Biopsy or surgically resected specimens from 72 patients with OPC were analyzed via immunohistochemical staining for SOD1 and SOD2. The proportion of stained cells within the tumor area was assessed. Associations between SOD1 and SOD2 expression, T classification, N classification, and stage were evaluated. Factors correlated with OS in OPC were also examined. No significant differences in SOD1 or SOD2 expression were observed concerning T or N classification, or stage. However, high SOD2 expression was identified as a significant poor prognostic factor for OS. Regardless of HPV status, SOD2 expression predicts poor prognosis in OPC. Evaluating SOD2 expression may help predict OPC prognosis.

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