Circulating Cytotoxic T Lymphocytes Associated Antigen-4 (CTLA-4) Levels and CTLA-4 Gene Polymorphism Role in Head and Neck Squamous Cell Carcinoma

Aim Aim: To determine the function of soluble CTLA-4 and the CTLA-4+49A/G gene polymorphism in patients with head and neck squamous cell carcinoma. Material and methods Materials and Methods: The current study recruited 180 subjects (90 patients with HNSCCs and comparable number apparently healthful persons as reference) from February 2024 to February 2025.These subjects selected from Medical City, Baghdad, Iraq. All individuals' genomic DNA was extracted from blood samples. To evaluate soluble (sCTLA-4), an enzyme-linked immunoassay kit was used. The Tetra-Primer Amplification Refractory System-Polymerase Chain Reaction (T-ARMS-PCR) was used to genotype and amplification of the CTLA-4 gene using specific primers. Results Results: As opposed to controls (median = 389.5 ng/ml, range = 160-1966 ng/ml), the median serum level of sCTLA-4 in patients was 1593.5 ng/ml (range = 1118-2000 ng/ml), which was noticeably higher. There was a significant difference (p=0.024) in the frequency of patients with the AA genotype compared to those did not (67.78% vs. 50%). Conversely, controls had a significantly higher frequency of the heterozygous genotype (AG) than patients (37.78% vs. 28.89%) (OR= 0.20, 95%CI=0.05-0.76, p=0.018). At allelic level, G allele was far more frequent in controls than patients (31.11% versus 17.78%). Conclusions Conclusion: The G allele and the heterozygous genotype (AG) may be regarded as protective factors from HNSCC, and AA genotype is risk factor for HNSCC. Soluble CTLA-4 rise remarkably in patients with HNSCC suggesting a function for this protein in pathogenesis of this disease.