Prevalence of p53 dysregulations in feline oral squamous cell carcinoma and non-neoplastic oral mucosa

Genomic landscape and gene expression profiles of feline oral squamous cell carcinoma

Feline oral squamous cell carcinoma (FOSCC) is a cancer of the squamous cell lining in the oral cavity and represents up to 80% of all oral cancers in cats, with a poor prognosis. We have used whole exome sequencing (WES) and RNA sequencing of the tumor to discover somatic mutations and gene expression changes that may be associated with FOSCC occurrence. FOSCC offers a potential comparative model to study human head and neck squamous cell carcinoma (HNSCC) due to its similar spontaneous formation, and morphological and histological features. In this first study using WES to identify somatic mutations in feline cancer, we have identified tumor-associated gene mutations in six cats with FOSCC and found some overlap with identified recurrently mutated genes observed in HNSCC. Four samples each had mutations in TP53, a common mutation in all cancers, but each was unique. Mutations in other cellular growth control genes were also found such as KAT2B and ARID1A. Enrichment analysis of FOSCC gene expression profiles suggests a molecular similarity to human OSCC as well, including alterations in epithelial to mesenchymal transition and IL6/JAK/STAT pathways. In this preliminary study, we present exome and transcriptome results that further our understanding of FOSCC.

Nuclear Epidermal Growth Factor Receptor Overexpression as a Survival Predictor in Oral Squamous Cell Carcinoma

The aim of this study was to determine, by immunohistochemical methods, the expression of nEGFR and markers of cell proliferation (Ki-67), cell cycle (mEGFR, p53, cyclin D1), and tumor stem cells (ABCG2) in 59 pathohistological samples of healthy oral mucosa, 50 oral premalignant changes (leukoplakia and erythroplakia), and 52 oral squamous cell carcinomas (OSCC). An increase in the expression of mEGFR and nEGFR was found with the development of the disease (p < 0.0001). In the group of patients with leukoplakia and erythroplakia, we found a positive correlation between nEGFR and Ki67, p53, cyclin D1, and mEGFR, whereas in the group of patients with OSCC, we found a positive correlation between nEGFR and Ki67, mEGFR (p < 0.05). Tumors without perineural (PNI) invasion had a higher expression of p53 protein than tumors with PNI (p = 0.02). Patients with OSCC and overexpression of nEGFR had shorter overall survival (p = 0.004). The results of this study suggest a potentially important independent role of nEGFR in oral carcinogenesis.

Genomic integration and expression of Felis catus papillomavirus type 2 oncogenes in feline Merkel cell carcinoma

The involvement of Felis catus papillomavirus type 2 (FcaPV2) in feline Merkel cell carcinoma (MCC) has been previously hypothesized. In this study, the expression and localization of FcaPV2 oncogene mRNA, the integration of FcaPV2 genes, and p53 mutations in feline MCC were examined by RNAscope in situ hybridization (ISH), whole genome sequencing (WGS), and Sanger DNA sequencing, respectively. Furthermore, the morphological and molecular characteristics of FcaPV2-positive (FMX-MCC01) and FcaPV2-negative (AS-MCC01) MCC cell lines were compared in vitro and in vivo using immunofluorescence, ISH, xenotransplantation into mice, and immunohistochemistry. ISH for FcaPV2 E6/E7 detected viral RNA in 18/21 FcaPV2-positive MCC and not in 1/1 FcaPV2-negative MCC. WGS of 2 FcaPV2-positive cases revealed the integration of FcaPV2 genes in both cases. In cultured cells and xenograft tissues of FMX-MCC01, most cells were positive for E6/E7 by ISH and p16CDKN2A, a few cells were positive for the retinoblastoma protein (pRb), and all cells were negative for p53. In cultured cells and xenograft tissues of AS-MCC01, all cells were negative for p16CDKN2A, most cells were positive for pRb, and some cells were positive for p53. Missense mutations in p53 were identified in 8/10 FcaPV2-positive and 1/1 FcaPV2-negative MCC. These results suggest that the expression of integrated FcaPV2 oncogenes might be associated with reduced expression of the tumor suppressor proteins pRb and p53 and might contribute to the development of feline MCC. On the other hand, p53 mutations may be involved in both FcaPV2-positive and FcaPV2-negative MCC tumorigenesis.

Circadian clock—A promising scientific target in oral science

The oral and maxillofacial organs play vital roles in chewing, maintaining facial beauty, and speaking. Almost all physiological processes display circadian rhythms that are driven by the circadian clock, allowing organisms to adapt to the changing environment. In recent years, increasing evidence has shown that the circadian clock system participates in oral and maxillofacial physiological and pathological processes, such as jaw and tooth development, salivary gland function, craniofacial malformations, oral carcinoma and other diseases. However, the roles of the circadian clock in oral science have not yet been comprehensively reviewed. Therefore, This paper provides a systematic and integrated perspective on the function of the circadian clock in the fields of oral science, reviews recent advances in terms of the circadian clock in oral and maxillofacial development and disease, dialectically analyzes the importance of the circadian clock system and circadian rhythm to the activities of oral and maxillofacial tissues, and focuses on analyzing the mechanism of the circadian clock in the maintenance of oral health, affecting the common diseases of the oral and maxillofacial region and the process of oral-related systemic diseases, sums up the chronotherapy and preventive measures for oral-related diseases based on changes in tissue activity circadian rhythms, meanwhile, comes up with a new viewpoint to promote oral health and human health.

Feline Oral Squamous Cell Carcinoma: A Critical Review of Etiologic Factors

Simple Summary

Feline oral squamous cell carcinoma (FOSCC) is the most common oral neoplasia in cats. This malignant tumor is locally invasive, has a high mortality rate, and its etiology is not yet known. A critical review about the potential etiologic factors of FOSCC was performed, considering publications between 2000 and 2022. The initial search resulted in 553 publications, with only 26 of these being included in the review. Sixteen studies were related to viral etiology and nine related to environmental factors such as exposure to tobacco smoke, ectoparasitic products, and the presence of oral comorbidities. When evaluated, feline papillomavirus was detected in 16.2% of samples of FOSCC. In the three studies focused on exposure to tobacco smoke, 35.2% (30/85) of cats with FOSCC had a history of this exposure. Among 485 cats with FOSCC, 6.4% had dental and oral pathology. The present study demonstrates that the available evidence on the etiology of FOSCC is still limited, however, there has been increasing interest in this topic.

Abstract

Feline oral squamous cell carcinoma (FOSCC) is the most common oral neoplasia in cats. This malignant tumor is locally invasive, has a high mortality rate, and its etiology is not yet known. In humans, head and neck squamous cell carcinoma is associated with tobacco smoke, alcohol consumption, and human papillomavirus infection. Herein, a critical review about the potential etiologic factors of FOSCC was performed, considering publications between 2000 and 2022, aiming to synthesize all available scientific evidence regarding this issue. Recommendations of the PRISMA statement and the Cochrane Collaboration were followed and the PubMed database searched by using the MeSH terms MeSH terms “oral”, “mouth”, “lingual”, “labial”, “gingiva”, “carcinoma”, “squamous”, and “feline”. The selection process for eligible studies was based on specific inclusion and exclusion criteria and the quality of the studies assessed. The initial search resulted in 553 publications, with only 26 of these being included in the review. Sixteen studies were related to viral etiology and nine related to environmental factors such as exposure to tobacco smoke, ectoparasitic products, and the presence of oral comorbidities. When evaluated, feline papillomavirus was detected in 16.2% of samples of FOSCC. In the three studies focused on exposure to tobacco smoke, 35.2% (30/85) of cats with FOSCC had a history of this exposure. The consumption of canned food and the use of deworming collars were associated, in only one publication, with a risk of neoplasia increased by 4.7 and 5.3 times, respectively. Among 485 cats with FOSCC, 6.4% had dental and oral pathology (i.e., periodontal disease or feline chronic gingivostomatitis). The present study demonstrates that the available evidence on the etiology of FOSCC is still limited, however, there has been an increasing interest on this topic. To better understand the role of the possible etiological factors of this aggressive disease, and model for its human counterpart, large, prospective multi-institutional studies are needed.

Feline Oncogenomics: What Do We Know about the Genetics of Cancer in Domestic Cats?

Simple Summary

Cancer is a significant cause of suffering and death in domestic cats. In humans, an understanding of the genetics of different types of cancers has become clinically important for all aspects of patient care and forms the basis for most emerging diagnostics and therapies. The field of ‘oncogenomics’ characterises the alterations of cancer-associated genes that are found in tumours. Such a thorough understanding of the oncogenome of human tumours has only been possible due to a high-quality reference genome and an understanding of the genetic variation that can exist between people. Although a high-quality reference genome for cats has only recently been generated, investigations into understanding the genetics of feline cancers have been underway for many years, using a range of different technologies. This review summarises what is currently known of the genetics of both common and rare types of cancer in domestic cats. Drawing attention to our current understanding of the feline oncogenome will hopefully bring this topic into focus and serve as a springboard for more much-needed research into the genetics of cancer in domestic cats.

Abstract

Cancer is a significant cause of morbidity and mortality in domestic cats. In humans, an understanding of the oncogenome of different cancer types has proven critical and is deeply interwoven into all aspects of patient care, including diagnostics, prognostics and treatments through the application of targeted therapies. Investigations into understanding the genetics of feline cancers started with cytogenetics and was then expanded to studies at a gene-specific level, looking for mutations and expression level changes of genes that are commonly mutated in human cancers. Methylation studies have also been performed and together with a recently generated high-quality reference genome for cats, next-generation sequencing studies are starting to deliver results. This review summarises what is currently known of the genetics of both common and rare cancer types in cats, including lymphomas, mammary tumours, squamous cell carcinomas, soft tissue tumours, mast cell tumours, haemangiosarcomas, pulmonary carcinomas, pancreatic carcinomas and osteosarcomas. Shining a spotlight on our current understanding of the feline oncogenome will hopefully serve as a springboard for more much-needed research into the genetics of cancer in domestic cats.

Correlation between p53 and Mdm2 expression with histopathological parameters in cattle squamous cell carcinomas

Background and Aim:

Squamous cell carcinoma (SCC) is the most common form of carcinoma in cattle. Histopathological grading systems have been utilized over several decades for estimating the malignancy of cattle SCCs. This study aimed to detect p53 and Mdm2 expression in different SCC cases in cattle and correlate their expression with the SCC histopathological grading.

Materials and Methods:

Cattle SCC cases were collected at the Veterinary Teaching Hospital in Nineveh. The SCC grading system categorized the cases histologically based on their differentiation grade into three groups: Well, moderately, and poorly differentiated. The SCC cases were subsequently verified for p53 and Mdm2 immunoexpression.

Results:

Fourteen of 16 examined cattle SCC samples tested positive for p53 expression. Moreover, 15 out of the 16 SCC samples tested positive for Mdm2 expression. The increased immunoreactivity of both p53 and Mdm2 was associated with a poor histological grading of the cattle SCC. There is a positive correlation between the nuclear expression of p53 and Mdm2, and the degree of differentiation and the number of mitotic figures in the examined cattle SCC samples.

Conclusion:

Our results demonstrate an increased p53 and Mdm2 expression in cattle SCC cases characterized by poor histopathological grading, thus suggesting an essential role of these molecules in the development of moderately and poorly differentiated SCC in cattle.

Oral cancer among Khat users: finding evidence from DNA analysis of nine cancer-related gene mutations

BACKGROUND

Khat leaves contain the alkaloid cathinone. Research shows that khat might provoke toxicity, mutagenicity, as well as carcinogenicity.

METHODS

Two groups were identified as khat abusers and were categorized by abuse time and diagnosis of oral squamous cell carcinoma (OSCC). Here, 41 participants from Group 2 were short-term khat users, and 42 participants were long-term khat users. The control group included 30 healthy individuals. The coding exons included nine cancer-related genes and were analysed. The histopathological research was conducted with H&E staining along with the TP53 protein expression by implementing immunohistochemical analyses.

RESULTS

Here, 41 short-term khat users carried seven somatic mutations in four out of nine cancer-related genes: 29/41(70.73%) ARID1A, 24/41(58.53%) MLH1, 34/41(82.92%) PIK3CA and 36/41(87.80%) TP53. The 42 long-term khat users incorporated nine somatic mutations in five out of nin ecancer-related genes: 40/42(95.23%) ARID1A, 36/42(85.71%) ARID2, 29/42(69.04%) PIK3CA, 27/42(64.28%) MLH1, and 35/42(83.33%) TP53. Every khat user had somatic mutations related to OSCC affecting the gingiva and the lower lip. TP53 protein expression was confirmed in all immunohistochemical oral tests. Carcinoma was also positive in the histopathological analysis.

CONCLUSIONS

Khat is a mutagenic and carcinogenic plant that provoked OSCC among short-term khat users (<15 years of use) and long-term users (>15 years of use).

Mutations in the tumor suppressor gene p53 in cattle are associated with enzootic bovine leukosis

Enzootic bovine leukosis (EBL) is a B-cell lymphoma caused by the bovine leukemia virus (BLV). Although an association between EBL and mutations in the bovine tumor suppressor gene TP53 (bTP53) has been suggested, the substantive incidence rate of bTP53 mutations in EBL cattle is still unclear. In this study, we investigated the complete sequence (exons 2-11) of bTP53 in tissue and peripheral blood leukocyte (PBL) samples obtained from 154 EBL cattle and 117 cattle without EBL (non-EBL cattle) to elucidate the correlation between bTP53 mutations and EBL. The detection frequencies of non-synonymous (NS) and deletion mutations in bTP53 in EBL cattle were significantly higher than those in non-EBL cattle in both tissue and PBL samples (p < 0.05). Among these mutations in EBL cattle, 73.7 % (42/54) were homologous to those of human TP53 (hTP53), which were previously detected in various tumors. It has been reported that 95.2 % (40/42) of these hTP53 mutations induced complete or partial loss of the transactivating function of its encoding protein, P53. Moreover, the BLV proviral load in tissue samples was significantly higher in cattle harboring bTP53 NS and deletion mutations than in cattle without these mutations in both EBL and BLV-infected non-EBL cattle (p < 0.05). Although the activity of the mutant variants of bP53 must be further investigated, our findings revealed that bTP53 mutations are involved in tumorigenesis in BLV-infected cells and EBL-associated carcinogenesis.

Utilizing feline oral squamous cell carcinoma patients to develop NQO1-targeted therapy

Developing effective therapies for the treatment of advanced head-and-neck squamous cell carcinoma (HNSCC) remains a major challenge, and there is a limited landscape of effective targeted therapies on the horizon. NAD(P)H:quinone oxidoreductase 1 (NQO1) is a 2-electron reductase that is overexpressed in HNSCC and presents as a promising target for the treatment of HNSCC. Current NQO1-targeted drugs are hindered by their poor oxidative tolerability in human patients, underscoring a need for better preclinical screening for oxidative toxicities for NQO1-bioactivated small molecules. Herein, we describe our work to include felines and feline oral squamous cell carcinoma (FOSCC) patients in the preclinical assessment process to prioritize lead compounds with increased tolerability and efficacy prior to full human translation. Specifically, our data demonstrate that IB-DNQ, an NQO1-targeted small molecule, is well-tolerated in FOSCC patients and shows promising initial efficacy against FOSCC tumors in proof-of-concept single agent and radiotherapy combination cohorts. Furthermore, FOSCC tumors are amenable to evaluating a variety of target-inducible couplet hypotheses, evidenced herein with modulation of NQO1 levels with palliative radiotherapy. The use of felines and their naturally-occurring tumors provide an intriguing, often underutilized tool for preclinical drug development for NQO1-targeted approaches and has broader applications for the evaluation of other anticancer strategies.

Validation of oral brushing as a non-invasive technique for the identification of feline oral squamous cell carcinoma by DNA methylation and TP53 mutation analysis

Feline oral squamous cell carcinoma (FOSCC) is a frequent and progressively invasive tumour. Early lesions are difficult to recognize based on the sole clinical examination and may be misinterpreted as non-neoplastic. Mutations of TP53 and epigenetic alterations of specific genes are present in FOSCC and may be early detected. Aim of this prospective study was to investigate the DNA methylation pattern of a 17-gene panel and TP53 mutational status of FOSCC cytological samples obtained by oral brushing. Results were compared with a control group, in order to validate this non-invasive procedure for the screening of FOSCC. In FOSCC, the same analyses were carried out on the corresponding histological sample, if available. Thirty-five FOSCC and 60 controls were included. Mutations of TP53 were detected in 17 FOSCC brushings (48%) and in none of the controls (P < .001). Six genes (ZAP70, FLI1, MiR124-1, KIF1A, MAGEC2 and MiR363) were differentially methylated in FOSCC and were included in a methylation score. An algorithm based on TP53 mutational status and methylation score allowed to differentiate FOSCC from controls with a 69% sensitivity and a 97% specificity (accuracy, 86%). In 19 FOSCC histological samples, TP53 mutational status was fully concordant with brushings and a positive methylation score was observed in all cases. These results are promising for the identification of FOSCC by oral brushing, although some factors may limit the accuracy of this technique and further studies are required to assess its reproducibility in clinical practice.

An Evolutionary Cancer Epigenetic Approach Revealed DNA Hypermethylation of Ultra-Conserved Non-Coding Elements in Squamous Cell Carcinoma of Different Mammalian Species

Background: Ultra-conserved non-coding elements (UCNEs) are genomic sequences that exhibit > 95% sequence identity between humans, mammals, birds, reptiles, and fish. Recent findings reported their functional role in cancer. The aim of this study was to evaluate the DNA methylation modifications of UNCEs in squamous cell carcinoma (SCC) from different mammal species. Methods: Fifty SCCs from 26 humans, 17 cats, 3 dogs, 1 horse, 1 bovine, 1 badger, and 1 porcupine were investigated. Fourteen feline stomatitis and normal samples from 36 healthy human donors, 7 cats, 5 dogs, 5 horses, 2 bovines and 1 badger were collected as normal controls. Bisulfite next generation sequencing evaluated the DNA methylation level from seven UCNEs (uc.160, uc.283, uc.416, uc.339, uc.270, uc.299, and uc.328). Results: 57/59 CpGs were significantly different according to the Kruskal–Wallis test (p < 0.05) comparing normal samples with SCC. A common DNA hypermethylation pattern was observed in SCCs from all the species evaluated in this study, with an increasing trend of hypermethylation starting from normal mucosa, through stomatitis to SCC. Conclusions: Our findings indicate that UCNEs are hypermethylated in human SCC, and this behavior is also conserved among different species of mammals.

Analysis of DNA methylation and TP53 mutational status for differentiating feline oral squamous cell carcinoma from non-neoplastic mucosa: A preliminary study

Feline oral squamous cell carcinoma (FOSCC) is characterized by high local invasiveness and early bone lysis. The late diagnosis largely limits the efficacy of therapy and increases treatment-related morbidity. The aim of this exploratory study was to assess the methylation pattern of 10 candidate genes and TP53 mutational status in histologic samples of FOSCC. Results were compared with normal oral mucosa and oral inflammatory lesions, in order to establish a gene panel for FOSCC detection. For 10 cats, the above analyses were also performed on oral brushing samples, in order to explore the utility of these methods for screening purposes. Thirty-one FOSCC, 25 chronic inflammatory lesions and 12 controls were included. TP53 mutations were significantly more frequent in the FOSCC (68%) than in the non-neoplastic oral mucosa (3%; P <.001). Based on lasso regression analysis, a step-wise algorithm including TP53, FLI1, MiR124-1, KIF1A and MAGEC2 was proposed. The algorithm allowed to differentiate FOSCC with 94% sensitivity and 100% specificity (accuracy, 97%). When applying the proposed algorithm on 10 brushing samples, accuracy decreased to 80%. These results indicate that the altered DNA methylation of specific genes is present in FOSCC, together with a significant proportion of TP53 mutations. Such alterations are infrequent in normal oral mucosa and chronic stomatitis in cats, suggesting their involvement in feline oral carcinogenesis and their utility as diagnostic biomarkers. Further studies on a high number of brushing samples will be needed to assess the utility of a screening test for the early detection of FOSCC.