Background
Gingivo-buccal squamous cell carcinoma (GB-OSCC) accounts for a major proportion of oral cancers in India and is frequently diagnosed at advanced stages, resulting in poor survival. The lack of validated, site-specific tissue biomarkers limits early risk stratification and prognostication. Proteomic profiling enables direct assessment of functional protein alterations associated with tumor aggressiveness and clinical outcomes.
Objectives
To identify differentially expressed proteins associated with disease progression in gingivo-buccal OSCC using proteomic analysis and to validate selected candidate biomarkers in an independent clinical cohort for their association with histopathological indicators of tumor aggressiveness.
Methods
Tumor tissues from 40 GB-OSCC patients were grouped into early-stage and locally advanced disease with or without treatment failure. Proteins were extracted and analyzed using two-dimensional gel electrophoresis (2DE) followed by MALDI-TOF mass spectrometry. Differentially expressed proteins were subjected to functional and pathway analysis using PANTHER and STRING databases. Four candidate proteins—Torsin A, α-Tubulin, Carbonic Anhydrase 1 (CA1), and Hemoglobin subunit beta (HBB)—were selected for validation by immunohistochemistry (IHC) in 125 retrospective clinical samples, including normal mucosa, dysplasia, and OSCC. Associations with clinicopathological parameters were analyzed statistically.
Results
Proteomic profiling identified 37 significantly upregulated proteins in GB-OSCC, enriched in pathways related to cytoskeletal organization, metabolic regulation, stress response, and angiogenesis. IHC validation demonstrated that CA1 and HBB expression correlated significantly with tumor size, degree of differentiation, muscle invasion, lymphovascular invasion, depth of invasion, tumor budding, and invasive tumor front grading (p < 0.001). Torsin A and α-Tubulin showed strong associations with tumor stage, invasion pattern, and adverse histopathological features, with significantly higher expression in OSCC compared to dysplasia and normal tissues (p < 0.001). Notably, α-Tubulin showed altered subcellular localization in invasive tumors, suggesting a role in tumor progression and cellular motility.
Conclusions / Implications for Practice and Policy
This study identifies and validates a novel tissue biomarker panel (Torsin A, α-Tubulin, CA1, and HBB) associated with aggressive tumor behavior in gingivo-buccal OSCC. These markers demonstrate potential utility for risk stratification of oral potentially malignant disorders and prognostication of established OSCC using routine IHC platforms. Incorporation of such biomarker panels into diagnostic workflows could improve early intervention strategies in high-burden, resource-limited settings, supporting more personalized treatment planning and follow-up protocols.