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.

• Klíčová slova
• ZNF395, Apoptosis, Etiologic field effect, Field cancerization, SCCOT,
• MeSH
• apoptóza * genetika   MeSH
• dlaždicobuněčné karcinomy hlavy a krku * genetika   patologie   MeSH
• dospělí MeSH
• homeostáza genetika   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádory jazyka * genetika   patologie   MeSH
• regulace genové exprese u nádorů MeSH
• senioři MeSH
• spinocelulární karcinom genetika   patologie   MeSH
• transkriptom MeSH
• upregulace * MeSH
• variabilita počtu kopií segmentů DNA MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH

Oral cancer is a paradigm of Slaughter's concept of field cancerization, where tumors are thought to originate within an area of cells containing genetic alterations that predispose to cancer development. The field size is unclear but may represent a large area of tissue, and the origin of mutations is also unclear. Here, we analyzed whole exome and transcriptome features in contralateral tumor-distal tongue (i.e. distant from the tumor, not tumor-adjacent) and corresponding tumor tissues of 15 patients with squamous cell carcinoma of the oral tongue. The number of point mutations ranged from 41 to 237 in tumors and from one to 78 in tumor-distal samples. Tumor-distal samples showed mainly clock-like (associated with aging) or tobacco smoking mutational signatures. Tumors additionally showed mutations that associate with cytidine deaminase AID/APOBEC enzyme activities or a UV-like signature. Importantly, no point mutations were shared between a tumor and the matched tumor-distal sample in any patient. TP53 was the most frequently mutated gene in tumors (67%), whereas a TP53 mutation was detected in only one tumor-distal sample, and this mutation was not shared with the matched tumor. Arm-level copy number variation (CNV) was found in 12 tumors, with loss of chromosome (Chr) 8p or gain of 8q being the most frequent events. Two tumor-distal samples showed a gain of Chr8, which was associated with increased expression of Chr8-located genes in these samples, although gene ontology did not show a role for these genes in oncogenic processes. In situ hybridization revealed a mixed pattern of Chr8 gain and neutral copy number in both tumor cells and adjacent nontumor epithelium in one patient. We conclude that distant field cancerization exists but does not present as tumor-related mutational events. The data are compatible with etiologic field effects, rather than classical monoclonal field cancerization theory. © 2022 The Authors. The Journal of Pathology published by John Wiley & Sons Ltd on behalf of The Pathological Society of Great Britain and Ireland.

• Klíčová slova
• CNV, SCCOT, SNV, chromosome 8, field cancerization,
• MeSH
• jazyk patologie   MeSH
• lidé MeSH
• nádory jazyka * genetika   MeSH
• nádory úst * patologie   MeSH
• spinocelulární karcinom * patologie   MeSH
• variabilita počtu kopií segmentů DNA MeSH
• Check Tag
• lidé MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

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.

• Klíčová slova
• MHC I, SCCOT, TAP1, field cancerization,
• MeSH
• analýza přežití MeSH
• biopsie MeSH
• časná detekce nádoru MeSH
• dospělí MeSH
• down regulace * MeSH
• jazyk chemie   patologie   MeSH
• lidé středního věku MeSH
• lidé MeSH
• nádorové biomarkery genetika   MeSH
• nádory jazyka genetika   mortalita   patologie   MeSH
• peptidový transportér TAP1 genetika   MeSH
• prognóza MeSH
• regulace genové exprese u nádorů MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• spinocelulární karcinom genetika   mortalita   patologie   MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• Názvy látek
• nádorové biomarkery MeSH
• peptidový transportér TAP1 MeSH
• TAP1 protein, human MeSH Prohlížeč

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.

• Klíčová slova
• blood markers, microarray, mucin 1, prognosis, squamous cell carcinomas of the oral tongue, validation,
• Publikační typ
• časopisecké články MeSH

Human keratin 36 (K36) is a member of the hair keratin family and is a marker of hair cortex differentiation. The human KRT36 gene is located on the long arm of chromosome 17 and belongs to the cluster of structurally unrelated acidic hair keratins. Recently, it has been reported that KRT36 mRNA is specifically expressed in normal tongue epithelium and downregulated in squamous cell carcinomas of the mobile tongue. Furthermore, KRT36 levels have been reported to be downregulated in clinically normal mobile tongue tissue that is adjacent to tumours, suggesting it could be a marker of pre-neoplastic changes. However, the exact role and the potential role of K36 in tongue tumour formation remains unclear. The aim of the present study was to investigate expression of K36 in a series of squamous cell carcinomas of the mobile tongue, normal mobile tongue and a small panel of other human tissues (normal tissue from the appendix, cervix, hair, lip, mamilla, nail, oesophagus, skin, thymus and vagina) and selected cancer tissue (cervical cancer, melanoma and basal cell carcinoma). Affinity purified polyclonal antibodies against K36 were generated and used for immunohistochemical analysis. The results revealed that in the normal tongue, K36 was detected specifically in the filiform papillae of the dorsal surface of the tongue. Additionally, none of the tongue cancer tissue samples were K36-positive. Immunostaining also revealed that K36 was expressed in nail beds, Hassal's corpuscles in the thymus and the hair cortex. However, K36 was not expressed in the squamous epithelia of the skin, cervix and oesophagus, and the squamous cells of cervical carcinomas, basal cell carcinoma or melanoma. The present data indicated that K36 may be inactivated in tumours of the tongue. However, whether this is part of the tumoural process or if it is an effect of the tumour itself remains to be elucidated.

• Klíčová slova
• keratin 36, mobile tongue, nail, squamous cell carcinoma, thymus,
• Publikační typ
• časopisecké články MeSH

Immune cells and cytolytic activity within the tumor microenvironment are being intensively studied. Through transcriptome profiling, immune cell enumeration using the xCell tool and cytolytic activity quantification according to granzyme A (GZMA) and perforin (PRF1) mRNA levels, we investigated immunoreactivity in tumor and/or tumor-free tongue tissue samples from 31 patients with squamous cell carcinoma of the oral tongue and 14 healthy individuals (control tongue tissues). We found significantly altered immune cell compositions (p < 0.001) and elevated cytolytic activity (p < 0.001) in tumor compared to tumor-free samples, and altered infiltration of a subset of immune cells (e.g. CD8+ T cells, p < 0.01) as well as increased cytolytic activity (p < 0.001) in tumor-free compared to control samples. Controlling for patient age at diagnosis and tumor stage, Cox regression analysis showed that high cytolytic activity in tumor-free samples associated with improved disease-free survival (hazard ratio= 4.20, 95% CI = 1.09-16.20, p = 0.037). However, the degree of cytolytic activity in tumor samples did not provide prognostic information. Taken together, our results show the presence of cancer-related immune responses in clinically tumor-free tongue in patients with squamous cell carcinoma of the oral tongue. Measuring cytolytic activity in tumor-free tongue samples contralateral to tumor might thus be an effective approach to predict clinical outcome.

• Klíčová slova
• cytolytic activity, oral tongue, prognosis, squamous cell carcinoma,
• MeSH
• cytotoxicita imunologická MeSH
• dlaždicobuněčné karcinomy hlavy a krku imunologie   mortalita   MeSH
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• nádorové mikroprostředí imunologie   MeSH
• nádory jazyka imunologie   mortalita   patologie   MeSH
• přežití bez známek nemoci MeSH
• prognóza MeSH
• retrospektivní studie MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mladý dospělý MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• práce podpořená grantem MeSH

Due to the high frequency of loco-regional recurrences, which could be explained by changes in the field surrounding the tumor, patients with squamous cell carcinoma of head and neck show poor survival. Here we identified a total of 554 genes as dysregulated in clinically tumor free tongue tissue in patients with tongue tumors when compared to healthy control tongue tissue. Among the top dysregulated genes when comparing control and tumor free tissue were those involved in apoptosis (CIDEC, MUC1, ZBTB16, PRNP, ECT2), immune response (IFI27) and differentiation (KRT36). Data suggest that these are important findings which can aid in earlier diagnosis of tumor development, a relapse or a novel squamous cell carcinoma of the tongue, in the absence of histological signs of a tumor.

• Klíčová slova
• RNA expression, field cancerization, tongue cancer,
• MeSH
• dospělí MeSH
• jazyk metabolismus   MeSH
• lidé středního věku MeSH
• lidé MeSH
• míra přežití MeSH
• nádorové biomarkery genetika   metabolismus   MeSH
• nádory jazyka genetika   metabolismus   patologie   MeSH
• následné studie MeSH
• prognóza MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• spinocelulární karcinom genetika   metabolismus   patologie   MeSH
• staging nádorů MeSH
• stanovení celkové genové exprese * MeSH
• studie případů a kontrol MeSH
• Check Tag
• dospělí MeSH
• lidé středního věku MeSH
• lidé MeSH
• mužské pohlaví MeSH
• senioři nad 80 let MeSH
• senioři MeSH
• ženské pohlaví MeSH
• Publikační typ
• časopisecké články MeSH
• srovnávací studie MeSH
• Názvy látek
• nádorové biomarkery MeSH