HPV

Abstract

Human papillomavirus (HPV) is established as causative in oropharyngeal squamous cell carcinomas (OSCCs), being detected in 50% to 80% of tumors by DNA in situ hybridization (ISH) and/or polymerase chain reaction. However, these tests do not assess viral transcription. Many consider E6/E7 messenger ribonucleic acid (mRNA) the best indicator of HPV status, but it has not been detected in situ in OSCC. We constructed tissue microarrays (TMAs) from a cohort of OSCC for which p16 immunohistochemistry and HPV DNA ISH were previously performed on whole sections.

Adenosquamous carcinoma (ADSC) of the head and neck is an aggressive variant of squamous cell carcinoma (SCC). Certain variants of head and neck SCC are human papillomavirus (HPV)-related and have better prognosis. The relationship of HPV to head and neck ADSC has not been investigated. We searched our files for the term "adenosquamous" and head and neck subsites and found cases from 1998 to 2009. The requisite histologic criteria were the presence of SCC combined with distinct gland formation and/or intracellular mucin.

Human papillomavirus (HPV) is associated with oropharyngeal squamous cell carcinomas. Persistent viral infection is postulated to lead to carcinogenesis, although infection of benign adjacent epithelium is not typically observed. It is known that immune evasive tumor cells can provide an ideal niche for a virus. The B7-H1/PD-1 cosignaling pathway plays an important role in viral immune evasion by rendering CD8+ cytotoxic T cells anergic. We hypothesized that HPV-related oropharyngeal squamous cell carcinomas express B7-H1 as a mechanism for immune evasion.

Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma has unique biology and better outcomes. p16 immunostaining is used as a surrogate marker for transcriptionally active HPV. Although diffuse staining is generally accepted as positive, the significance of partial staining has not been established, nor has the cutoff for extent of p16 staining that should be used to identify a tumor as HPV-related. From three other large studies utilizing p16 immunohistochemistry, we identified all cases with partial positive staining.

AIMS:

Human papillomavirus is well established in oropharyngeal squamous cell carcinoma as both causative and prognostic, but its significance in non-oropharyngeal tumours is unclear. In particular, the significance of finding viral DNA is not known. We sought to evaluate nonoropharyngeal squamous cell carcinomas for transcriptionally-active human papillomavirus and to compare this with the presence of viral DNA.

METHODS:

Evidence for transcriptional activation of the viral oncoproteins E6 and E7 is regarded as the gold standard for the presence of clinically relevant human papillomavirus (HPV), but detection of E6/E7 mRNA requires RNA extraction and polymerase chain reaction amplification-a challenging technique that is restricted to the research laboratory. The development of RNA in situ hybridization (ISH) probes complementary to E6/E7 mRNA permits direct visualization of viral transcripts in routinely processed tissues and has opened the door for accurate HPV detection in the clinical care setting.

Spindle cell carcinoma is an uncommon variant of squamous cell carcinoma characterized by spindled or pleomorphic cells which appear to be a true sarcoma but are actually epithelial. Some head and neck squamous cell carcinoma variants can be human papillomavirus (HPV)-related and have improved outcomes. We sought to determine if spindle cell carcinomas are associated with transcriptionally-active HPV. Cases of spindle cell carcinoma were retrieved from department files.

BACKGROUND:

A relationship between human papillomavirus (HPV) infection and papillary squamous cell carcinoma (PSCC) has been suggested. However, to date, no studies have thoroughly and directly evaluated for transcriptional activity of the virus or the clinicopathologic significance of HPV-positive PSCC. Forty-eight cases of PSCC were retrieved from our surgical pathology database and were reviewed by 4 study pathologists, with tumors defined as SCC with a significant component of papillary growth in the tumor. Immunohistochemical analysis for p16 and p53 was performed.