Molecular and clinical aspects of HNSCC in the Republic of Moldova

Abstract Introduction : Complex molecular characterization and integrated approaches in the basic research of HNSCC provide new insights into the understanding and treatment of these tumors. Mutations in the TP53 gene, HPV infection, aberrant DNA methylation are just a few factors that have a direct link with the clinical and psychological condition of patients with this type of cancer. In the Republic of Moldova, these aspects are insufficiently studied. Methods : The study included 128 patients with HNSCC from whom the following samples were collected: fresh tumor tissue, NAT, blood, and saliva. All samples, except saliva, were tested for 3 mutations in the TP53 gene, while DNA isolated from tumor tissue was also tested for global DNA methylation assessment. HPV genotypes were tested from saliva. HPV positive samples were retested from tumor tissue. Results : Of the total analyzed samples for TP53 pathogenic variants, in 30 (23.44%) samples there were detected one or two mutations, and in 9 samples (7.03%) – it was detected the presence of two mutations simultaneously. HPV infection was detected in 17 samples (13.28%). Regarding global DNA methylation, in patients with a high degree of exposure to stress, a 44% lower level was observed (median 13.5 ng/ml) compared to those with moderate and low exposure (median 20.5 ng/ml ). Conclusion : The most frequent mutation identified in the TP53 gene was the 524G>A substitution and the frequency of high-risk HPV infection in HNSCC patients from Moldova was 13.28%. The high degree of stress exposure showed a lower level of global methylation.