alt=Photo of rhinoscope used to visualise the oropharynx through the nose CT scan in transverse plane, viewed from below, showing a contrast enhancing right tonsil mass due to<unk> +alt=CT Scan of right tonsil<unk>  Biopsy Initial diagnosis requires visualisation of the tumour either through the mouth or endoscopically through the nose using a rhinoscope, illustrated to the right, followed by biopsy. Differentiating<unk> +OPC from<unk> -OPC<unk> +OPC is usually diagnosed at a more advanced stage than<unk> -OPC, with 75–90% having involvement of regional lymph nodes. Furthermore,<unk> +OPC is more likely to be poorly differentiated with nonkeratinized or basaloid cells. Genetic signatures of<unk> + and<unk> - OPC are different.<unk> +OPC is associated with expression level of the E6/E7 mRNAs and of p16.<unk> 16 E6/E7-positive cases are histopathologically characterized by their verrucous or papillary (nipple like) structure and koilocytosis of the adjacent mucosa. Approximately 15% of HNSCCs are caused by<unk> 16 infection and the subsequent constitutive expression of E6 and E7, and some<unk> -initiated tumors may lose their original characteristics during tumor progression. High-risk<unk>  types may be associated with oral carcinoma, by cell-cycle control dysregulation, contributing to oral carcinogenesis and the overexpression of mdm2, p27 and cathepsin B.<unk> +OPC is not merely characterized by the presence of<unk> -16: only the expression of viral oncogenes within the tumor cells plus the serum presence of E6 or E7 antibodies is unambiguously conclusive for<unk> +OPC. There is not a standard<unk>  testing method in head and neck<unk> s, both in situ hybridization (ISH) and polymerase chain reaction (PCR) are commonly used. Both methods have comparable performance for<unk>  detection, however it is important to use appropriate sensitivity controls. Immunohistochemistry (IHC) staining of the tissue for p16 is frequently used as a cost-effective surrogate for<unk>  in OPC, compared to ISH or PCR but there is a small incidence of<unk> -negative p16-positive disease accounting for about 5% of<unk> -OPC.
HPV-positive oropharyngeal cancer
Tobacco
Hepatitis C and HIV coinfection
Branchial cleft cyst
Circumcision and HIV
Oral florid papillomatosis
Hormone receptor positive breast tumor
Human papillomavirus infection