Molecular and Phylogenetic Analysis of Human Papillomavirus Using L1 Gene in Oral Squamous Cell Carcinoma Patients in Baghdad, Iraq

Abstract

Oral squamous cell carcinoma (OSCC) is the most common malignant neoplasm of the oral mucosa. Human papillomavirus (HPV) virus cause a broad scope of diseases from benign to invasive tumors, types 16 and 18 classified as carcinogenic to humans. This study aimed to provide the first molecular characterization of HPV types in Iraq. Thirty-five unstimulated whole saliva samples were collected from histopathologically confirmed patients with oral cancer were enrolled in this study. Genomic DNA was extracted from exfoliating cells to amplify HPV-DNA using HPV-L1 gene sequence primers by polymerase chain reaction method (PCR), the viral genotyping was performed using direct sequencing method. HPV genotypes identified were deposited in GenBank. HPV DNA was detected in 20 of 35 OSCC patients representing (57%).The most frequent HPV genotypes were HPV-18 accounting for (75%) (15 out of 20 patients) followed by HPV-16 accounting for (20%) (4 out of 20), and HPV-11 accounting for (5%) (5 out of 20 patients). This study highlights the high-risk HPV genotypes in OSCC patients and their phylogenetic analysis tree and their homology to the ancestral sequence which may indicate emerging of a new biological entity of HPV-positive OSCC with a potential sexually transmission.