B lymphocytes are important players in immune responses to cancer. However, their composition and function in head and neck squamous cell carcinoma (HNSCC) has not been well described. Here, we analyzed B cell subsets in HNSCC (n = 38), non-cancerous mucosa (n = 14) and peripheral blood from HNSCC patients (n = 38) and healthy controls (n = 20) by flow cytometry. Intratumoral B cells contained high percentages of activated (CD86+), antigen-presenting (CD86+/CD21−) and memory B cells (IgD−/CD27+). T follicular helper cells (CD4+/CXCR5+/CD45RA−/CCR7−) as key components of tertiary lymphoid structures and plasma cells made up high percentages of the lymphocyte infiltrate. Percentages of regulatory B cell varied depending on the regulatory phenotype. Analysis of humoral immune responses against 23 tumor-associated antigens (TAA) showed reactivity against at least one antigen in 56% of HNSCC patients. Reactivity was less frequent in human papillomavirus associated (HPV+) patients and healthy controls compared to HPV negative (HPV−) HNSCC. Likewise, patients with early stage HNSCC or MHC-I loss on tumor cells had low TAA responses. Patients with TAA responses showed CD4+ dominated T cell infiltration compared to mainly CD8+ T cells in tumors without detected TAA response. To summarize, our data demonstrates different immune infiltration patterns in relation to serological TAA response detection and the presence of B cell subpopulations in HNSCC that can engage in tumor promoting and antitumor activity. In view of increasing use of immunotherapeutic approaches, it will be important to include B cells into comprehensive phenotypic and functional analyses of tumor-associated lymphocytes.

In patients presenting with CUP syndrome, p16 immunohistochemistry can serve to locate the primary cancer in the oropharynx. It is a positive prognostic indicator in patients with those heterogeneous cancers.

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Different studies have shown that HPV16‐positive OPSCC can be subdivided based on integration status (integrated, episomal and mixed forms). Because we showed that integration neither affects the levels of viral genes, nor those of virally disrupted human genes, a genome‐wide screen was performed to identify human genes which expression is influenced by viral integration and have clinical relevance. Thirty‐three fresh‐frozen HPV‐16 positive OPSCC samples with known integration status were analyzed by mRNA expression profiling. Among the genes of interest, Aldo‐keto‐reductases 1C1 and 1C3 (AKR1C1, AKR1C3) were upregulated in tumors with viral integration. Additionally, 141 OPSCC, including 48 HPV‐positive cases, were used to validate protein expression by immunohistochemistry. Results were correlated with clinical and histopathological data. Non‐hierarchical clustering resulted in two main groups differing in mRNA expression patterns, which interestingly corresponded with viral integration status. In OPSCC with integrated viral DNA, often metabolic pathways were deregulated with frequent upregulation of AKR1C1 and AKR1C3 transcripts. Survival analysis of 141 additionally immunostained OPSCC showed unfavorable survival rates for tumors with upregulation of AKR1C1 or AKR1C3 (both p <0.0001), both in HPV‐positive (p ≤0.001) and ‐negative (p ≤0.017) tumors. OPSCC with integrated HPV16 show upregulation of AKR1C1 and AKR1C3 expression, which strongly correlates with poor survival rates. Also in HPV‐negative tumors, upregulation of these proteins correlates with unfavorable outcome. Deregulated AKR1C expression has also been observed in other tumors, making these genes promising candidates to indicate prognosis. In addition, the availability of inhibitors of these gene products may be utilized for drug treatment.

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