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PURPOSE: The field cancerization concept indicates the presence of pre-cancerous changes in clinically normal tissue surrounding the tumor. In squamous cell carcinoma of the oral tongue (SCCOT) which is infrequently linked to human papillomavirus infection, we have previously reported that clinically normal tongue contralateral to tumor (NTCT) is molecularly abnormal. Here, combining our transcriptomic and genomic data, we aimed to investigate the contribution of molecular changes in NTCT to cancer development.

METHODS: Microarray gene expression data of 14 healthy controls, 23 NTCT and 29 SCCOT samples were investigated to characterize transcriptional profiles in NTCT. Whole exome sequencing and RNA-sequencing data of paired NTCT and tumor samples from 15 SCCOT patients were used to study correlation between copy number variation and differential gene expression.

RESULTS: Using supervised multivariate partial least squares discriminant analysis, a total of 61 mRNAs that distinguish NTCT from healthy tongue were selected. Functional enrichment analysis of the 22 upregulated genes showed increased "positive regulation of nitrogen compound metabolic process" in NTCT. All 12 genes involved in this process have roles in apoptosis (anti- and/or pro-apoptotic). Compared to healthy controls, Zinc Finger Protein 395 (ZNF395), a pro-apoptotic tumor suppressor located on chromosome 8p, was the only gene showing increased mRNA level in NTCT whereas decreased in SCCOT. Given the frequent loss of chromosome 8p in SCCOT, the impact of ZNF395 copy number variation on gene expression was further examined, revealing a positive correlation between copy number and mRNA level (correlation coefficient = 0.572, p < 0.001).

CONCLUSION: NTCT is susceptible to malignant transformation, where tissue homeostasis is maintained at least partly through regulation of apoptosis. Loss of the pro-apoptotic gene ZNF395 could thus initiate cancer development.

Transporter associated with antigen processing 1 (TAP1) and TAP2 serve pivotal roles in adaptive immunity. Tumor cells often show reduced antigen presentation on their surface as one mechanism to escape immune recognition. Whether downregulation of TAPs is a common mechanism of tumor immune evasion in squamous cell carcinoma of the oral tongue (SCCOT) is unclear. In the present study, samples from 78 patients with SCCOT and 17 patients with benign hyperplastic tongue lesions were analyzed for TAP1 and TAP2 expression by immunohistochemistry. The percentage of positive cells and staining intensity were scored. Associations with clinicopathological variables and survival outcome were also investigated. The results demonstrated that TAP1 and TAP2 levels were highly associated with each other in individual samples and were upregulated in SCCOT compared with benign lesions (P<0.001). The proportion of TAP1‐ or TAP2‐positive tumor cells was >80% in all but two of the tumors, whereas 25.6 and 23.0% of the tumors showed weak intensity of TAP1 and TAP2, respectively. There were no significant associations with clinicopathological variables or survival outcomes between TAP‐intermediate/strong and TAP‐weak tumors. However, in patients <70 years old and with early stage SCCOT, male patients had better outcomes than female patients (log‐rank P<0.05), and the best outcome was observed in male patients with intermediate/strong TAP expression. In conclusion, loss of TAP was not a frequent event in SCCOT and stronger TAP expression in male patients was associated with improved survival, providing further evidence for sex‐specific immune modulation in cancer.

Oral cancers are surrounded by epithelium that histologically might seem normal, but genetically has aberrations. In patients with squamous cell carcinoma of the oral tongue (SCCOT), it is therefore important to study not only the tumor but also the clinically tumor-free contralateral tongue tissue that remains in the patient after treatment to map changes of prognostic and/or diagnostic value. The transporter associated with antigen processing (TAP) dimer is a key factor in the process of activating cytotoxic T cells. By downregulating the expression of TAP, tumor cells can escape cytotoxic T cell recognition. Biopsies from tumor and clinically tumor-free contralateral tongue tissue in 21 patients with SCCOT were analyzed together with tongue biopsies from 14 healthy individuals, which served as the control group. Dividing patients into TAP1-high and TAP1-low groups according to the median TAP1 level in tumor-free samples showed that patients with lower TAP1 mRNA levels in tumor-free samples had better overall (p = 0.003) and disease-free survival (p = 0.002). The results showing that TAP1 levels in tumor-free tongue tissue contralateral to the SCCOT correlate with survival is an important contribution to early diagnosis and follow up of SCCOT.

Mucin 1 (MUC1) is a membrane-bound and secreted glycoprotein that has a protective role in surface epithelia. We recently demonstrated that MUC1 mRNA expression was upregulated in tumour-free tongue tissues adjacent to squamous cell carcinoma of the oral tongue (SCCOT) compared with that in the tumour tissues. The present study investigated MUC1 protein in SCCOT tissue and serum from patients with squamous cell carcinoma of the head and neck (SCCHN) at different sub-sites. The results from immunohistochemistry demonstrated that all SCCOT tissues expressed MUC1; however, the protein levels were not correlated with MUC1 mRNA levels in the same tumours. Furthermore, serum MUC1 level was lower in patients with SCCOT, tonsil SCC and gingival SCC compared with that in healthy subjects; however, the difference was only significant for patients with SCCOT (P=0.0421). No correlation was seen between MUC1 level in tumour tissues and MUCI level in serum from the same patients. The absence of correlation between MUC1 protein and mRNA levels in SCCOT tissues emphasized the importance of validating genomic data in clinical samples. Although significant MUC1 downregulation was observed in the serum of patients with SCCOT, there was a large variation within the groups, suggesting that MUC1 may not be used as a biomarker for these types of tumors.

Background: Circulating markers are attractive molecules for prognosis and management of cancer that allow sequential monitoring of patients during and after treatment. Based on previous protein profiling data, circulating interleukin 1 receptor antagonist (IL-1Ra) was evaluated as a potential diagnostic and prognostic marker for squamous cell carcinomas of the head and neck (SCCHN). In this study, we aimed at confirming the clinical relevance of plasma IL-1Ra in SCCHN and exploring its potential as a prediction marker for SCCHN.

Methods: Plasma from 87 patients with SCCHN, control plasma from 28 healthy individuals and pre-diagnostic plasma from 44 patients with squamous cell carcinoma of the oral tongue (SCCOT) and 88 matched controls were analysed with IL-1Ra electrochemiluminescence immunoassays from mesoscale diagnostics.

Results: Plasma IL-1Ra was found to be up-regulated in patients with oral tongue, gingiva and base of tongue tumours compared to healthy individuals (p < 0.01). IL-1Ra levels positively correlated with tumour size (p < 0.01) and body mass index (p = 0.013). Comparing pre-diagnostic plasma to the matched controls, similar IL1-Ra levels were seen (p = 0.05).

Conclusion: The anti-inflammatory cytokine IL-1Ra could be a diagnostic marker for SCCHN, whereas its potential as a cancer prediction marker was not supported by our data.

The p53 homologue p63 produces six different isoforms that are important in development of epithelial tissues and squamous cell carcinoma of the head and neck (SCCHN). In SCCHN, the expression of p63 isoforms is highly complex, with over-expression of DeltaNp63 and p63beta isoforms in many tumours. To date, little is known about the functions of different DeltaNp63 isoforms and elucidating the distinctive properties of DeltaNp63 isoforms will help to clarify how they influence tumour biology. By gene expression profiling of SCCHN cells over-expressing the DeltaNp63 isoforms we identified different effects of the three isoforms, with DeltaNp63beta being more effective at gene induction than DeltaNp63alpha and DeltaNp63gamma, whereas DeltaNp63gamma was most effective at repressing gene expression. Thus, tumours expressing even low levels of DeltaNp63beta or DeltaNp63gamma may have distinct clinicopathological characteristics important for metastasis and therapeutic response. Induction of cyclooxygenase-2 (Cox-2) was shown by each isoform and data were confirmed by independent quantitative RT-PCR and western blotting. No direct binding of DeltaNp63 to the Cox-2 promoter could be seen, neither could any evidence for Cox-2 induction as a consequence of activated NF-kappaB pathway responses be found. As Cox-2 is known to inhibit radiotherapy responses in SCCHN patients, data indicate an additional mechanism through which DeltaNp63 acts to promote cell survival and influence therapeutic response of SCCHN. MIAME-compliant data have been deposited in the MIAME Express database (Accession No. E-MEXP-1842). Copyright (c) 2009 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.