INVESTIGATION OF HLA GENES, HLA MOLECULES AND OTHER FACTORS IN PATIENTS WITH ORAL SQUAMOUS CELL CARCINOMA

Abstract

Major histocompatibility complex class I-related chain A (MICA) is a ligand of Natural killer group 2, member D (NKG2D) receptor. Recent studies have shown that MICA is upregulated in tumours from the epithelial origin, playing a key role in immunological surveillance and different alleles are associated with diseases related to NK activity. The aim of our study was to analyse the associations of MICA polymorphism with oral squamous cell carcinoma (OSCC). Twenty-seven patients with histologically proven OSCC were included in the study. The majority of patients had G2-G3 tumours according to Anneroth's classification. The control group included healthy subjects from the Bulgarian population. MICA genotyping was performed by PCR-SSO kit (LABType SSO MICA, OneLambda) and PCR-SBT. Our results showed a statistically significant protective association for MICA*12:01 allele (Pc<0.05, OR-0.07), encoding a full- length protein. Interestingly this allele had a higher frequency in the healthy Bulgarian population compared to other European populations. With the highest frequency in patients with OSCC was observed MICA*08:01 allele, encoding truncated protein. However, the difference with the control group was with a borderline significance (Pc=0.053). Although our data are preliminary considering the small number of patients analyzed, the associations observed support the model that alleles are encoding truncated, ectopic and soluble MICA molecules play an important role in OSCC by down-regulation of NKG2D on NK and CD8+ T cells leading to aberrant immunological surveillance.

Keywords

• biomarkers
• oral squamous cell carcinoma
• HLA