Undifferentiated carcinoma of the oropharynx: a human papillomavirus-associated tumor with a favorable prognosis

Human papillomavirus-associated adenocarcinoma of the base of tongue: potentially actionable genetic changes

While human papillomavirus (HPV)-positive squamous and adenosquamous carcinomas of the oropharynx have been well characterized, HPV-associated pure adenocarcinomas are exceptionally rare. Herein we report the clinicopathologic features of one such HPV-associated adenocarcinoma of the base of tongue (BOT). A 70 year-old male presented with a 2.8 cm base of tongue mass and lymphadenopathy. Immunohistochemically, the adenocarcinoma was p63 negative and p16 positive. HPV positivity was shown by in situ hybridization. Features of salivary type tumor or metastasis from a distant primary were absent. IonTorrent™ semiconductor sequencing analysis for 739 cancer-associated mutations in 46 actionable cancer genes was performed and PIK3CA exon 9 (p.E545K) and MET exon 2 (p.E168D) mutations were identified. No PIK3CA or MET amplification was identified by fluorescence in situ hybridization. A re-review of archival HPV-positive oropharyngeal squamous cell carcinomas (n = 89, 1983-2013) showed no additional cases of adenocarcinoma. The clinical follow-up for the three previously reported cases of HPV-associated adenocarcinoma of the BOT was updated. All previously reported cases were tested and were negative for PIK3CA exon 9 and 20 and MET exon 2 mutations. These findings offer a molecular basis for potential therapeutic use of PIK3CA inhibitors in a subset of patients with HPV-associated adenocarcinoma of BOT.

Human papillomavirus prevalence and prognostic implication in oropharyngeal squamous cell carcinomas

BACKGROUND

Human papillomavirus (HPV)-related oropharyngeal squamous cell carcinoma (SCC) is associated with favorable survival. The purpose of this study was to evaluate the prevalence and prognostic significance of the HPV infection through both the p16 expression status and the oncogenic HPV DNA viral load.

METHODS

A retrospective chart review was conducted on all patients treated for oropharyngeal SCC between January 2007 and June 2009. P16 expression status by immunohistochemistry and HPV DNA viral load by quantitative polymerase chain reaction (qPCR) were evaluated on routine pretreatment tumor samples.

RESULTS

One hundred thirty-three patients (94 men and 39 women) were included in the study. Mean age was 59 years. One hundred twenty-two lesions (92%) were localized to lymphoid areas. Sixty-seven patients (50%) were p16+, and 87 patients (65%) harbored HPV DNA. The p16+/HPV DNA+ profile (48%) was associated with the most favorable prognosis. HPV16 was responsible for the majority of the infections (89%).

CONCLUSION

HPV is common among oropharyngeal SCC in France, and acts as an independent prognostic factor.

Molecular diagnostic alterations in squamous cell carcinoma of the head and neck and potential diagnostic applications

Head and neck squamous cell carcinoma (HNSCC) is a common malignancy that continues to be difficult to treat and cure. In many organ systems and tumor types, there have been significant advances in the understanding of the molecular basis for tumorigenesis, disease progression and genetic implications for therapeutics. Although tumorigenesis pathways and the molecular etiologies of HNSCC have been extensively studied, there are still very few diagnostic clinical applications used in practice today. This review discusses current clinically applicable molecular markers, including viral detection of Epstein-Barr virus and human papillomavirus, and molecular targets that are used in diagnosis and management of HNSCC. The common oncogenes EGFR, RAS, CCND1, BRAF, and PIK3CA and tumor suppressor genes p53, CDKN2A and NOTCH are discussed for their associations with HNSCC. Discussion of markers with potential future applications is also included, with a focus on molecular alterations associated with targeted therapy resistance.

Human papillomavirus-16 associated adenocarcinoma NOS of base of tongue

The causative role of human papillomavirus (HPV) in a subset of squamous cell carcinomas of the oropharynx (OSCC) is now well established with HPV-16 being detected in approximately 92% of HPV-positive OSCC in North America. Recently HPV has also been found in some non-squamous oropharyngeal carcinomas including adenosquamous carcinomas, neuroendocrine carcinomas, and undifferentiated "lymphoepithelioma-like" carcinomas. Herein, we report a HPV-16 positive adenocarcinoma NOS arising in the base of the tongue of a non-smoker, 64 year-old male. To our knowledge, this is the first time this association has been clearly documented. The adenocarcinoma was diffusely positive for p16 and HPV-16 was demonstrated by in situ hybridization and linear array analysis. Q-PCR demonstrated a viral load of 4 copies per cancer cell, whereas qRT-PCR for E6/E7 transcript levels were 30 copies per 1,000 human ribosomal protein large P0 (RPLP0) reference gene. The presence of HPV in non-squamous oropharyngeal carcinomas raises the possibility that HPV is also involved in the carcinogenesis of some uncommon carcinomas of the region.

HPV-related squamous cell carcinoma variants in the head and neck

The great majority of HPV-related carcinoma of the oropharynx is nonkeratinizing squamous cell carcinoma. More recently, an increasing number of squamous cell carcinoma variants that are HPV positive are being reported in the oropharynx, as well as in other head and neck sites. As a result, several clinical and pathologic questions have emerged. Importantly, questions raised include whether the virus is biologically active and involved in the pathogenesis of these tumors, and whether there are clinical implications with regard to patient outcome and treatment modality changes that may be needed in HPV-related variants. Examples of HPV-related squamous cell carcinoma variants that will be addressed here include: basaloid squamous cell carcinoma, undifferentiated carcinoma, adenosquamous carcinoma, papillary squamous carcinoma, and small cell carcinoma. Some investigations have suggested a favorable prognosis in some variants, analogous to that of the conventional nonkeratinizing (basaloid) carcinoma, while others showed poorer outcome. So far, the number of studies on this subject is limited and the number of cases evaluated in each investigation is few. Because of this, it is prudent at this stage not to alter management protocols as a result of identification of HPV in these variants and to await additional studies.

HPV-associated neuroendocrine carcinoma of the oropharynx: a rare new entity with potentially aggressive clinical behavior

High-grade neuroendocrine carcinoma of the head and neck is an aggressive neoplasm which rarely arises in the oropharynx. Here we report a series of 8 oropharyngeal neuroendocrine carcinomas associated with both human papillomavirus (HPV) infection and tobacco exposure. The tumor occurred predominantly in male patients (6 of 8) at a mean age of 59 years. Histologically, these cases were all classified as poorly differentiated neuroendocrine carcinoma (small cell carcinoma) with high mitotic activity [mean 53.3 mitoses per 10 HPF], necrosis, high nuclear-to-cytoplasmic ratio, and nuclear molding. One case also exhibited a moderately differentiated component, and one other case had a component of squamous cell carcinoma with basaloid features. Neuroendocrine differentiation was confirmed by immunoreactivity for synaptophysin and/or chromogranin A in all cases. P63 staining was negative, except in 1 case. Seven of the 8 cases showed strong and diffuse p16 expression, a surrogate marker for high-risk HPV infection. HPV infection was confirmed in 6 of these 7 cases by HPV in situ hybridization and/or polymerase chain reaction analysis. HPV subtypes 16, 18, and 33 were identified in 1 case each by polymerase chain reaction testing. Six of the 7 patients for whom clinical history was available presented with advanced disease (4 with regional lymph node metastases, 1 with distant metastases, and 1 with distant and locoregional metastases). Disease recurred in 5 of the 6 patients with available clinical follow-up, with 3 developing distant metastases to brain, bones, lung, pleura, adrenal glands, and pancreas. These 3 cases were all from the HPV-positive group. In summary, neuroendocrine carcinoma of the oropharynx represents a rare novel HPV-associated entity with high-grade histologic features and aggressive clinical behavior.