High-risk human papilloma virus was not detected in a Norwegian cohort of oral squamous cell carcinoma of the mobile tongue.

OBJECTIVES: The presence of and the causative role of high-risk human papilloma virus (HPV) is a subject of controversy in oral squamous cell carcinoma (OSCC). The disagreement can be related to the misclassification of OSCC as oropharyngeal squamous cell carcinoma and/or lack of standard detection methods. This study aimed to examine the presence of transcriptionally active high-risk HPV in a homogenous Norwegian cohort of primary and second primary OSCC of the mobile tongue (oral tongue squamous cell carcinoma-OTSCC). METHODS: Tissue microarrays containing formalin-fixed and paraffin-embedded cores of 146 OTSCC from the anterior 2/3 of the tongue (n = 128 primary and n = 18 second primary) from a multicentric Norwegian cohort were examined for the presence of high-risk HPV by DNA- and RNA-in situ hybridization (ISH) assays and p16 immunohistochemistry. RESULTS: Transcriptionally active HPV (E6/E7 mRNA) was not identified in any of the OTSCC specimens. In parallel, no tumors were positive for HPV by DNA ISH. Although, 61 (42%) OTSCC demonstrated p16 positivity with varying staining intensity and subcellular localization, only two cases demonstrated strong and uniform p16-staining (both cytoplasmic and nuclear) in >70% of cancer cells. The absence of transcriptionally active high-risk HPV in this cohort of OTSCC indicates that high-risk HPV is an unlikely causative factor in the present material.

Prognostic impact of PD-L1 in oropharyngeal cancer after primary curative radiotherapy and relation to HPV and tobacco smoking.

Background: Incidence of oropharyngeal squamous cell carcinoma (OPSCC) is rising rapidly in many western countries due to Human papillomavirus (HPV) and tobacco smoking, with a considerable overlap. Immunotherapy directed at the PD1/PD-L1 axis have shown promise in head and neck cancer and other cancer types. PD-L1 expression may indicate a poorer prognosis, and at the same time indicate a possible benefit of anti-PD-L1 immunotherapeutic agents. The primary aim of this study was to establish the prognostic effect of PD-L1 expression after primary curative radiotherapy alone.Material and methods: A cohort of 303 OPSCC patients treated with primary, curative intended radiotherapy was established. PD-L1 expression was evaluated by immunohistochemistry on formalin fixed, paraffin embedded tissue sections. PD-L1 positivity was defined as a Combined Positive Score (CPS) ≥1, indicating staining of either tumor cells, lymphocytes or macrophages.Results: Median follow-up was 5.3 years. With 199 deaths, there was no difference in overall survival between patients with PD-L1+ and PD-L1- tumors (adjusted hazard ratio [aHR] and 95% confidence interval [CI]: 1.0 [0.71-1.4]). Also, locoregional failure was similar between the two groups (aHR 1.1 [CI: 0.68 - 1.7]). Tumors were PD-L1+ in 76% of cases, significantly more among HPV p16+ tumors (82% vs. 70%, p = .01). Interestingly, higher prevalence of PD-L1+ expression was seen in HPV p16+ patients with <10 pack-years of tobacco-smoking (93%) compared to HPV p16+ smokers (76%) or HPV p16-negative patients (70%) (p = .003).Conclusion: PD-L1 expression had no prognostic significance in OPSCC patients treated with primary radiotherapy alone. A substantial proportion of OPSCC tumors show PD-L1 overexpression, especially in HPV p16+ tumors in patients with little or no smoking history.

Detection of mRNA of Telomerase Protein in Benign Naevi and Melanomas Using RNAscope.

Telomerase is reactivated in most cancers and is possibly an early driver event in melanoma. Our aim was to test a novel in situ hybridization technique, RNAscope, for the detection of human telomerase reverse transcriptase (hTERT) mRNA in archival formalin-fixed, paraffin-embedded (FFPE) tissue and to compare the mRNA expression of melanomas and benign naevi. Furthermore, we wanted to see if hTERT mRNA could be a diagnostic or prognostic marker of melanoma. In situ hybridization for the detection of hTERT mRNA was performed on FFPE tissue of 17 melanomas and 13 benign naevi. We found a significant difference in the expression of hTERT mRNA between melanomas and benign naevi (P<0.001) and the expression of hTERT mRNA correlated with Breslow thickness (ρ=0.56, P=0.0205) and the Ki67 proliferation index (ρ=0.72, P=0.001). This study showed that RNAscope was a reliable in situ hybridization method for the detection of hTERT mRNA in FFPE tissue of melanomas and benign naevi. hTERT mRNA was more abundantly expressed in melanomas compared with benign naevi, but cannot be used solely as a diagnostic marker due to an overlap in expression. The hTERT mRNA expression in melanomas correlated with the prognostic markers Breslow thickness and the Ki67 index indicating a prognostic potential of hTERT mRNA.

MelanA-negative spindle-cell associated melanoma, a distinct inflammatory phenotype correlated with dense infiltration of CD163 macrophages and loss of E-cadherin.

MelanA is a known melanocyte marker and is important in melanoma diagnostics. Some tumours, however, show loss of MelanA expression and may therefore be difficult to distinguish from tumours of mesenchymal origin. Pure spindle-cell melanoma is a rare event, and little is known about its biological background and prognosis. However, morphological changes towards a more mesenchymal shape and cellular dedifferentiation may correlate with reactivation of important developmental programmes (epithelial-to-mesenchymal transition) and disseminative tumour cell properties. Inflammation and CD163+ macrophages have been shown to be important inducers of E-cadherin and cell-to-cell adhesion loss, a pivotal and final event of epithelial-to-mesenchymal transition. In a cohort of 385 patients with melanoma, we located nine tumours with a clonal MelanA expression, defined as a tumour section with a distinct MelanA-negative clone next to a MelanA-positive clone. Interestingly, MelanA-negative clones correlated significantly with an augmented inflammatory response of tumour-infiltrating macrophages (CD163+), complete loss of E-cadherin and a spindle-shaped morphology, irrespective of ulcerated status. These cases show the inflammatory heterogeneity of melanoma, which may have important diagnostic, prognostic and therapeutic implications for the patients. We show that melanomas harbour cell clones that bear strong resemblance to tumour-associated macrophages, a pivotal player in a tumour-supporting microenvironment. Interestingly, this distinct inflammatory phenotype is associated with loss of MelanA expression, the presence of spindle-shape morphology and complete loss of E-cadherin, considered as possible markers of poorly differentiated and more invasive tumour cells.