Transporter Associated with Antigen Processing Proteins (TAP-1 and TAP-2) Gene Expression of MHC-I Downregulated in Oral Squamous Carcinoma.

Background: TAP-1 and TAP-2 are crucial proteins for loading antigenic peptides after proteasome-mediated endogenous processing of the MHC-I (Major Histocompatibility Complex- I) pathway. Our study aimed to explore the Transporter Associated with Antigen Processing proteins (TAP-1 and TAP-2) in oral squamous cell carcinoma and premalignant oral lesions.

Methods: We recruited a total of 135 subjects from the outpatient department of the ENT unit of our institute. Real-time Polymerase Chain Reaction (PCR) was used to evaluate the levels of TAP-1 and TAP-2 gene expression in pre-cancerous and oral squamous carcinoma samples. Additionally, we measured the circulating levels of inflammatory markers using an automated biochemistry analyzer.

Results: In the current study, we found that the subjects with oral squamous cell carcinoma had lower expressions of the TAP 1 and TAP 2 genes than precancerous oral subjects of OSMF, leukoplakia, and OLP. In oral squamous carcinoma subjects, we found a 1.7- and 2.1-fold change in gene expression of TAP-1 and TAP-2, respectively, compared to control subjects. Furthermore, we observed an increase in levels of metabolic inflammatory biomarkers of CRP, ESR, and ferritin in oral squamous carcinoma subjects compared to premalignant cases and controls, indicating the presence and aggravation of systemic inflammation.

Conclusion: The study revealed that subjects with oral squamous cell carcinoma have lower TAP 1 and TAP 2 gene expression than premalignant control subjects, thus affecting MHC-I processing, which ultimately affects the functioning of the immune system. These results have the potential to improve our understanding of disease pathophysiology and provide more targeted treatment options.