Background
Virus-related cancers are malignancies caused by specific viruses, such as human papillomavirus (HPV), hepatitis B virus, and human T-cell leukemia virus, contributing significantly to the global cancer burden through persistent infection and oncogenic transformation. The current study aimed to develop a robust HPV-16 detection method for formalin-fixed cancer specimens. Materials and
Conclusions
The established protocol should be applicable to various cancer tissues for analyzing the association with HPV-16 infection.
Methods
To prevent false negatives resulting from DNA fragmentation, a DNA quality check step was added. Additionally, this study used multiplex polymerase chain reaction (PCR) covering the entire HPV-16 genome to mitigate effects caused by viral sequence variation. To prove this concept, we analyzed genomic DNA extracted from oropharyngeal cancer tissues known as HPV-16-positive. Subsequently, the protocol was tested on oral squamous cell carcinoma (OSCC) samples in our cohort. Given the wide variation in HPV-16 positivity in previous studies, it remains elusive how frequently HPV-16 is positive in OSCC.
Results
The results showed faint bands or smears in the multiplex PCR of 7 out of 112 cases. Droplet digital PCR confirmed variable positivity levels of HPV-16, suggesting two scenarios of HPV-16 positivity in cancer tissue: cancer cells derived from infected cells or only a portion being HPV-16-positive. Finally, we comprehensively analyzed the case and identified the integration of a deleted HPV-16 genome into the intronic region of the host gene TMEM94 on chromosome 17. To the best of our knowledge, this is the first evidence showing the integration of HPV-16 in OSCC cells and providing its complete viral sequence. Conclusions: The established protocol should be applicable to various cancer tissues for analyzing the association with HPV-16 infection.