Immunohistochemical expression of DNA methyltransferases 1, 3a and 3b in oral leukoplakias and squamous cell carcinomas

Over-expression of DNA methyltransferases DNMT1, DNMT3a and DNMT3b has been reported in various cancers and precancerous lesions.

Objective

To investigate DNMT1, DNMT3a and DNMT3b enzymes in oral squamous cell carcinoma (SCC) and leukoplakia, and their relationship with histopathologic/clinical parameters.

Study design

Immunohistochemistry was carried out to evaluate the three DNMTs in 60 samples of oral SCC and 37 samples of oral leukoplakia.

Results

DNMT3a immunoreactivity in the three groups of oral SCC (39.8%) was significantly higher than in control (22.6%) (ANOVA, Student–Newman–Keuls test, P < 0.05), but not when compared to oral leukoplakia groups (28.2%). For DNMT1 and DNMT3b, there were no statistically significant differences between oral SCC groups (65% and 74.7%), oral leukoplakia groups (68.3% and 70.9%) and control (65.4% and 76.5%). There was a significantly higher mean percentage of DNMT1 immunoreactivity in non-smokers (ANOVA, P = 0.048), and a higher DNMT3a immunoreactivity in alcohol users (ANOVA, P = 0.01).

Conclusions

Higher DNMT3a immunopositivity may be associated with oral SCC and alcohol use, whilst lower levels of DNMT1 may be related with smoking habit. However, there was a significantly higher mean percentage of DNMT1 immunoreactivity in non-smokers (ANOVA, P = 0.048), and a higher DNMT3a immunoreactivity in alcohol users (ANOVA, P = 0.010).     

Reduction of syndecan-1 expression during lip carcinogenesis

Background:  Actinic cheilitis (AC) is an oral pre-cancerous lesion that sometimes develops into lip squamous cell carcinoma (SCC). Syndecan-1, a transmembrane heparan sulfate proteoglycan, modulates cell-proliferation, adhesion, migration and angiogenesis. Malignant epithelial cells often down-regulate their own syndecan-1 production, and are capable of inducing aberrant syndecan-1 expression in stromal cells. The aim of this study was to evaluate the variations in syndecan-1 expression during lip carcinogenesis, in normal lip (NL), AC and well-differentiated lip SCC.
Methods:  Biopsies of NL vermillion ( n  = 19), AC ( n  = 23) and lip SCC ( n  = 24) were stained immunohistochemically for syndecan-1.
Results:  Syndecan-1 expression was significantly reduced in AC and lip SCC as compared to NL ( P  < 0.05), with a significant reduction in lip SCC as compared to AC ( P  < 0.0001). In lip SCC lesions, syndecan-1 expression at the epithelium overlying the tumor was increased when compared to the tumor itself ( P  < 0.03), but was significantly reduced as compared to AC and NL ( P  < 0.001).
Conclusion:  The results showed that epithelial syndecan-1 expression is reduced as lip carcinogenesis progresses (NL>AC>lip SCC), suggesting that syndecan-1 could be a useful marker of malignant transformation in the lip.     

Therapeutic approaches for actinic cheilitis: therapeutic efficacy and malignant transformation after treatment

Actinic cheilitis (AC) is a sun-induced premalignant lesion. AC is a clinical term housing a wide pathological spectrum ranging from hyperkeratosis to invasive squamous cell carcinoma. The aim of this systematic review was to examine the therapeutic efficacy of different approaches in clinical, histological, and cosmetic terms, and the malignization rate after treatment. A systematic search was undertaken in October 2016 and updated in April 2019 at MEDLINE (from 1966), Embase (from 1980), and Proceedings Web of Science (Conference Proceedings Citation Index-Science (CPCI-S) from 1990) databases. The search strategy was ((“actinic” or “solar”) AND (“cheilitis”)) using both medical subject headings (MeSH) and freetext. A total of 392 potentially eligible reports were identified. After the selection procedure, 20 articles were included. It was concluded that surgical treatment is the first line of treatment for AC and has proved useful for the clinical and pathological control of the disorder. However, there was no evidence of effective treatment in preventing malignant transformations. Non-surgical procedures showed less consistent results, although drug therapy may improve the results obtained by other therapeutic approaches.     

Actinic cheilitis: clinical and pathologic characteristics in 65 cases

OBJECTIVE: The purpose of this study was to determine the clinical and histopathologic presentation of actinic cheilitis. STUDY DESIGN: A retrospective study on 65 patients attending an Oral Medicine clinic in Greece over a 10 year period. For each case the demographic, clinical and histopathologic information were evaluated. RESULTS: The mean age at the time of diagnosis was 53.1 +/- 11.4 years. Thirty-nine patients (60%) used tobacco in any form. An outdoor occupation was indicated for 43 (66.2%) patients. The location of the lesions of actinic cheilitis was in all cases on the lower lip. Actinic cheilitis appeared in three forms; white non-ulcerated lesions (29%), erosions or ulcers of the lip (48%), mixed white and erosive (23%). The histopathologic characteristics included increased thickness of keratin layer, alterations of the thickness of spinous cell layer, epithelial dysplasia, connective tissue changes, perivascular inflammation and basophilic changes of connective tissue. In 11 cases (16.9%) the presence of squamous cell carcinoma was observed. CONCLUSIONS: This case-series highlights varied clinical presentation of actinic cheilitis among whom a high proportion developed squamous cell carcinoma.     

Distinct expression of perforin and granzyme B in lip and oral cavity squamous cell carcinoma

J Oral Pathol Med (2011) 40 : 380–384 Background: Perforin and granzyme B (GB) are the main constituents of cytotoxic T‐lymphocyte granules, and they have important roles in preventing the initiation and progression of cancer. Methods: The aim of this study was to compare the expression of CD8⁺/perforin⁺ double‐staining and GB⁺ cells, by immunohistochemistry, in primary oral cavity squamous cell carcinoma (OCSCC), lip squamous cell carcinoma (LSCC), non‐dysplastic leukoplakia (LK), dysplastic LK, actinic cheilitis (AC), oral lichen planus (LP) and normal oral mucosa. Results: Our results showed a higher expression of CD8⁺/perforin⁺ and GB⁺ cells in LSCC when compared with the samples of OCSCC, non‐dysplastic and dysplastic LK, AC, oral LP and normal oral mucosa. In addition, increased CD8⁺/perforin⁺ and GB⁺ cell numbers were observed in all pre‐malignant lesions (non‐dysplastic LK, dysplastic LK, AC) when compared with the control. Conclusions: Perforin and GB proteins may contribute to antitumoural immunity, leading to the direct killing of tumour cells; however, it seems to occur more effectively in LSCC than OCSCC.     

Expression of apoptotic and cell proliferation regulatory proteins in actinic cheilitis

BACKGROUND: Actinic cheilitis (AC) is a pre-malignant lesion caused by ultraviolet (UV) radiation. The apoptotic proteins p53, bax, bcl-2, and the proliferation marker Ki-67, are known to play an important role in UV-exposed skin and carcinomas, therefore, these markers were assessed in AC and compared with normal lip and oral mucosa. METHODS: AC (n = 13), normal lip (n = 7) and oral mucosa (n = 6) biopsies were stained immunohistochemically for p53, bax, bcl-2 and Ki-67, to determine their expression and distribution. RESULTS: p53 was over-expressed in AC as compared with normal lip and oral mucosa (P < 0.003). Although bcl-2 expression was higher in AC than in oral mucosa (P < 0.002), it was significantly reduced as compared with normal lip (P < 0.04). Bax expression remained unchanged, and Ki-67 was significantly increased in AC and normal lip as compared with oral mucosa (P < 0.05). CONCLUSION: The results suggest that DNA-damaged cells by UV radiation in AC are eliminated by apoptosis.     

Increased mast cell density and protease content in actinic cheilitis

BACKGROUND: Actinic cheilitis (AC) is a pre-malignant lesion caused by ultraviolet (UV) radiation and characterized by epithelial and connective tissue alterations. Mast cells (MCs), key contributors to solar elastosis in murine UV-irradiated skin, were characterized in order to assess their potential contribution to connective tissue degeneration in AC. METHODS: Actinic cheilitis (n = 15) and normal lip (n = 8) biopsies were stained immunohistochemically for tryptase and enzymehistochemically for chymase to determine MC density and protease content. MC subpopulations (i.e. MC(T) containing only tryptase, and MC(TC) containing chymase and tryptase) and their distribution were also determined. RESULTS: Mast cells and their proteases were increased in AC as compared with normal lip (P < 0.0001), and appeared degranulated especially around elastotic areas. MC(T) predominated over MC(TC) in AC and normal lip (P < 0.05). However, in AC MC(T) were increased in the epithelium/connective junction and connective area (P < 0.05), while in normal lip MC(T) predominated in connective and submucosal areas (P < 0.05). CONCLUSION: The results suggest that increased MC density and protease content may contribute to elastosis formation in AC. In addition, changes in MC(T) distribution may favor AC malignization.     

Differential infiltration of CD8+ and NK cells in lip and oral cavity squamous cell carcinoma

J Oral Pathol Med (2010) 39 162–167 Background: CD8⁺ and natural killer (NK) cells have been considered the most effective cells in the combat of cancer, contributing to better prognosis and longer survival. Methods: The aim of this study was to evaluate the population of CD8⁺ and NK cells, by immunohistochemistry, in samples of oral cavity squamous cell carcinoma (OCSCC) and lip squamous cell carcinoma (LSCC), leukoplakia, actinic cheilitis, and healthy oral mucosa (control). The relationship of CD8⁺ and NK cells with survival data, lymph node metastasis, tumor size, and proliferative index was also evaluated. Results: The number of peritumoral and intratumoral CD8⁺ and NK cells was significantly higher in LSCC, when compared with control, pre‐malignant lesions, and OCSCC. A higher proportion of peritumoral CD8⁺ cells demonstrated correlation with a lower neoplastic proliferative index. Moreover, patients with OCSCC with a high density of peritumoral CD8⁺ cells showed a tendency towards a longer survival time. Conclusions: The differential CD8⁺ and NK cells infiltration in oral SCC might reflect a distinctive tumor microenvironment with a favorable local cytotoxic immune response against neoplastic cells.     

COX-2和唇癌血管生成相关性研究

目的：探讨环氧化酶-2（COX-2）表达与唇癌血管生成的关系。方法：免疫组化检测唇癌COX-2、诱导型一氧化氮合酶（iNOS）、血管内皮生长因子（VEGF）的表达,并测定肿瘤微血管密度（MVD）。结果：唇癌COX-2表达与VEGF、iNOS表达密切相关（P〈0．05）,唇癌COX-2表达阳性组和阴性组的MVD有显著差异（P〈0．01）。结论：COX-2表达和唇癌血管生成密切相关,iNOS和VEGF可能参与COX-2对肿瘤血管生成的促进作用。     

应用快速冰冻活检确定唇癌手术边缘的研究

目的：评价快速冰冻活检在唇癌手术治疗中的意义。方法：分析168例经手术治疗的唇癌患者术中快速冰冻活检确认手术边缘的检查结果。手术边缘发现浸润癌或原位癌记为阳性边缘。结果：168例患者中有22例发现阳性边缘（13．10％）,168例中10例（5．95％）术后复发。结论：快速冰冻活检评估手术边缘是控制手术切除范围的可靠方法,可有效减少术后复发及术后放疗,但阴性手术边缘并不能保证术后的零复发率。     

Eotaxin expression in oral squamous cell carcinomas with and without tumour associated tissue eosinophilia

AIM: Eotaxin is a powerful and selective eosinophil chemoattractant. The purpose of this study was to compare the expression of eotaxin in oral squamous cell carcinomas with and without tumour associated tissue eosinophilia (TATE). The mechanisms that control the recruitment of eosinophils to these tumours are not clearly established. METHODS: A total of 60 patients with oral squamous cell carcinomas (OSCC) with TNM stages II and III, located in the tongue, oral floor, retromolar area and inferior gingiva were divided in two groups: 1--OSCC with intense eosinophilic inflammatory infiltrate and 2--OSCC with absent/low eosinophilic inflammatory infiltrate. The eotaxin expression was analyzed by immunohistochemistry using standard streptavidin-biotin-peroxidase complex technique with monoclonal (mouse anti-human eotaxin) and polyclonal (rabbit anti-human eotaxin) antibodies. RESULTS: The eotaxin expression was identified in normal oral mucosa as well as in both OSCC groups including malignant epithelial cells, eosinophils, neutrophils, plasma cells and fibroblasts. The eosinophils showed intense immunopositivity for eotaxin. CONCLUSION: These results suggest that the eotaxin expressed in oral squamous cell carcinomas, mainly derived from eosinophils, is probably involved in the mechanisms of eosinophils chemotaxis to the tumour and in the maintenance of TATE in these malignant tumours.