Epithelial oral mucosal cells: Do they behave differently when exposed to oral carcinogens?

Epithelial-mesenchymal transition related to bone invasion in oral squamous cell carcinoma

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Presence of epithelial-mesenchymal transition markers in tumor-bone interface.

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Dominant infiltrative pattern in bone tissue is associated with lower survival.

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E-cadherin-positive cases were associated with tobacco smoking.

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Vimentin-positive cases were associated with tumors under 4 cm.

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Twist could be strongly involved in bone invasion and in disease progression.

Introduction

Bone invasion is an important prognostic factor in oral squamous cell carcinoma, leading to a lower survival rate and the use of aggressive treatment approaches. Epithelial-mesenchymal transition (EMT) is possibly involved in this process, because it is often related to mechanisms of cell motility and invasiveness. This study examined whether a panel of epithelial-mesenchymal markers are present in cases of oral squamous cell carcinoma with bone invasion and whether these proteins have any relationship with patients’ clinical-pathological parameters and prognostic factors.

Methods

Immunohistochemical analysis of E-cadherin, twist, vimentin, TGFβ1, and periostin was performed in paraffin-embedded samples of 62 oral squamous cell carcinoma cases.

Results

The analysis revealed that most cases (66%) presented with a dominant tumor infiltrative pattern in bone tissue, associated with lower survival rates, when compared with cases with a dominant erosive invasion pattern (P = 0.048). Twenty-seven cases (43%) expressed markers that were compatible with total or partial EMT at the tumor-bone interface. There was no association between evidence of total or partial EMT and other demographic or prognostic features. E-cadherin-positive cases were associated with tobacco smoking (P = 0.022); vimentin-positive cases correlated with tumors under 4 cm (P = 0.043). Twistexpression was observed in tumors with a dominant infiltrative pattern (P = 0.041) and was associated with the absence of periostin (P = 0.031).

Conclusion

We observed evidence of total or partial EMT in oral squamous cell carcinoma bone invasion. The transcription factor twist appears to be involved in bone invasion and disease progression.

Cytologic features of oral squamous cell carcinoma in an Indo-Pacific bottlenose dolphin (Tursiops aduncus): Papanicolaou stain and immunocytochemistry using liquid-based cytology

Although oral cytology using Papanicolaou stain is useful for the early detection of oral premalignant lesions and squamous cell carcinoma (SCC) in people, little work has been conducted on this topic in veterinary medicine. This paper describes the features of oral cytology using Papanicolaou stain and immunocytochemistry on liquid-based cytology slides in a case of oral SCC in an Indo-Pacific bottlenose dolphin (Tursiops aduncus). In this case, dysplastic cells with koilocyte-like changes and SCC cells were identified using the Papanicolaou stain. These cells were positive for p53 using an immunocytochemistry analysis. A cytologic diagnosis of SCC was made. We believe that the early detection of premalignant oral lesions and SCC in dolphins can be significantly improved with cytology using liquid-based cytology, Papanicolaou staining, and immunocytochemistry.

Early effects of cigarette smoke extract on human oral keratinocytes and carcinogenesis in head and neck squamous cell carcinoma

Background

Cigarette smoking is a major risk factor for head and neck squamous cell carcinoma. Still, the effect of cigarette smoke on the molecular level is unclear. The aim of the present study was to investigate the early effects of cigarette smoke on carcinogenesis of head and neck squamous cell carcinoma.

Methods

Human oral keratinocytes were exposed for 1 week to standardized cigarette smoke extract, and subsequently RT‐quantitative PCR array was performed. Protein expression of dysregulated genes was determined by immunohistochemistry in tissue samples of oral squamous cell carcinoma, oral leukoplakia, and tonsil mucosa.

Results

RT‐PCR revealed upregulation of ITGA‐2 and MMP‐1, whereas TEK receptor tyrosine kinase was downregulated in human oral keratinocytes. ITGA‐2 and MMP‐1 were significantly overexpressed in tissue samples of oral squamous cell carcinoma in comparison to normal mucosa (P <.01 in all experiments).

Conclusion

Upregulation of ITGA‐2 and MMP‐1 induced by cigarette smoke contributes significantly to oral carcinogenesis.

Cytopathological tests for early detection of oral carcinogenesis

The carcinogenesis in the oral cavity occurs as a multistep process and is often preceded by potentially malignant lesions. The main risk factors for the development of oral cancer are smoking and alcohol intake. The current challenge is to identify patients at greatest risk for the development of oral cancer using noninvasive and effective methods. The aim of this study is to evaluate the microsatellite mutations in the 9p21 locus, the cell proliferative activity, the pattern of epithelial desquamation, and the nucleus/cytoplasm ratio of exfoliated epithelial cells. Cytopathological samples were collected from 131 individuals divided into four groups: control (n = 26), alcohol-smoking (n = 32), leukoplakia (n = 38), and the oral squamous cell carcinoma group (OSCC, n = 35). From the cytological scraping, a slide was silver impregnated for Ag-stained nucleolar organizer region analysis and another slide was stained using the Papanicolaou technique. The remaining cells were used for DNA extraction, followed by PCR amplification and capillary electrophoresis. The cell proliferation velocity rate was higher in the leukoplakia and OSCC groups compared with the control group (P < 0.05). The leukoplakia group showed increased anucleated scales, whereas the nucleated superficial predominated in the control group and the parabasal cells in the OSCC group (P < 0.05). An increased nucleus/cytoplasm ratio was detected only in the OSCC group (P < 0.05). The 9p21 locus mutation frequency was higher in the alcohol-smoking and leukoplakia groups. 9p21 analysis and Ag-stained nucleolar organizer region methods are promising for the screening and monitoring of individuals at higher risk for the development of oral cancer.