Elevated ras p21 expression in oral premalignant lesions and squamous cell carcinomas in Taiwan

Expression of ras p21 oncoproteins was examined in histological sections of oral squamous cell carcinoma (SCC), epithelial dysplasia, epithelial hyperkeratosis and normal oral mucosa using antibodies to ras p21 with an immunoperoxidase technique. Ras p21-positive staining was found in 47 of 51 (92.2%) cases of oral SCC, 4 of 4 (100%) cases of epithelial dysplasia, 7 of 7 (100%) cases of epithelial hyperkeratosis, and 1 of 6 (16.7%) cases of normal oral mucosa. The positive staining rate of ras p21 in oral SCC, epithelial dysplasia or epithelial hyperkeratosis was significantly higher than that in normal oral mucosa (P<0.05). No correlation was found between ras p21 expression and patient age, tumour location, tumour size, clinical staging or histological differentiation of SCC. However, a significant positive correlation was found between ras p21 expression and patients' sex (P<0.05) or regional lymph node status (P<0.05). A significant positive correlation was also discovered between ras p21 expression and patients' smoking habits (P<0.01), as well as daily or total betel quid (BQ) consumption (P<0.05). Of the 47 immunostain-positive SCC patients, specimens from 6 patients were also obtained after chemotherapy, when ras p21 expression was found to be reduced. These results indicate that ras p21 over expression may play an important role in the initiation and progression of oral SCCs in patients who are smokers and BQ chewers.     

A case of upper gingiva carcinoma with chronic graft‐versus‐host disease after allogenic bone marrow transplantation

Oral squamous cell carcinoma (OSCC) is one of the most common solid tumours occurring after haematopoietic stem cell transplantation (HSCT), especially in patients with chronic graft‐versus‐host‐disease (cGVHD). We describe a case of OSCC that developed in a 51‐year‐old male 22 years after he had received allogeneic HSCT from his human leukocyte antigen‐identical sister as a treatment for acute myelocytic leukaemia. The patient had presented with multiple white patchy lesions on the palatal gingiva and mucosa 16 years after HSCT; these lesions were consistent with the clinical features of cGVHD. Six years later, oral examination and biopsy revealed upper gingival squamous cell carcinoma (SCC) in areas of cGVHD, and he underwent tumour excision. Follow‐up examination at 2 years and 4 months after the operation revealed no evidence of recurrence of local SCC or metastasis of the cervical lymph node. The current case highlights the susceptibility of patients with cGVHD to the development of OSCC even two decades after HSCT. Therefore, we recommend careful long‐term follow‐up of the oral cavity for patients with cGVHD.     

The use of antigen retrieval for immunohistochemical detection of p53 over-expression in malignant and benign oral mucosa: a cautionary note

The tumour suppressor gene p53 is frequently mutated in neoplasia. Since mutant p53 protein is often over-expressed, mutation can be indirectly detected by immunocytochemical techniques. As microwave antigen retrieval is becoming a widespread method for increasing the antigenicity of paraffin sections, we investigated the application of this technique to p53 immunohistochemical staining of oral mucosa specimens. Paraffin sections of 22 squamous cell carcinomas (SCC) and 36 benign lesions were immunohistochemically stained with and without antigen retrieval. Without antigen retrieval p53 over-expression was observed in 6/22 SCC and 1/36 benign lesions. Following antigen retrieval positive staining was observed in 15/22 SCC and 35/36 benign lesions. Staining in benign lesions was confined to basal and parabasal cells and could reflect normal functioning of wild-type p53. We conclude that antigen retrieval increases the sensitivity of p53 immunoreactivity. but such staining is not specific for malignancy and should be interpreted with caution.     

Alteration of integrin expression in oral squamous cell carcinomas

OBJECTIVE: This study examines the intensity of expression of beta 1, alpha 2, alpha 3, alpha 5, alpha 6 integrin subunits in oral squamous cell carcinoma (SCC) as opposed to normal oral epithelium, and the intensity of expression and distribution pattern of the above subunits in relation to tumour differentiation grade. MATERIALS AND METHODS: Cryostat sections of 25 cases of oral SCC and 15 cases of normal oral epithelium were studied by immunohistochemistry (APAAP method). RESULTS: The intensity of expression of beta 1, alpha 2 (Pearson chi 2 P < 0.001) and alpha 6 (Test for Trend P < 0.05) integrin subunits was reduced significantly in SCC compared to normal oral epithelium. All integrin subunits were mainly expressed in the peripheral cell layer of tumour islands. No correlation was found between the intensity of integrin expression and the degree of differentiation in SCC. The same applied to the distribution pattern of the integrin subunits. By means of cross examination of all integrins, the loss of intensity of alpha 2 beta 1 integrin expression was found to have the strongest correlation with oral SCC (Ordered Logistic Regression). CONCLUSIONS: Reduced intensity of expression of all subunits was found in oral SCC compared to normal epithelium. Further investigation is needed to determine whether alpha 2 beta 1 integrin expression can be used as a prognostic evaluator for the behaviour of the disease.     

Alteration in the expression of cdk4 and cdk6 proteins in oral cancer and premalignant lesions

J Oral Pathol Med (2010) 39 : 793–799 Background: Cdk4 and cdk6, key players in G1 phase, have been shown to play an important role in the development of oral squamous cell carcinoma (OSCC). This study investigated the expression of these two proteins in OSCC and premalignant lesions including oral leukoplakia (OL) with and without dysplasia and determined if alterations in the expression of these two proteins could be used as markers of malignant transformation. Methods: Expressions of cdk4 and cdk6 were evaluated in 61 samples including OSCC, OL with and without dysplasia and normal oral mucosa using immunohistochemistry method. Nuclear staining of the keratinocytes was considered positive and the percentage of positive cells was calculated. Results: Expression of cdk4 was found in 11/15 (73.33%) OSCC, 13/14 (92.85%) OL with dysplasia, 13/20 (65%) OL without dysplasia and 3/12 (25%) normal mucosa. Expression of cdk6 was detected in 9/15 (60%) OSCC, 3/14 (21.43%) OL with dysplasia, 5/20 (25%) OL without dysplasia and 1/12 (8.33%) normal mucosa. In cdk4 stained specimens, the frequency of positive cases and the percentage of positive cells in normal mucosa was significantly lower than OL with dysplasia and OSCC. For cdk6 staining, the prevalence of positive cases and the percentage of positive cells in normal mucosa were significantly lower than OSCC. Conclusions: Overexpressions of cdk4 and cdk6 were observed in OSCC, indicating that these two proteins play a crucial role in OSCC. The aberrant expression of cdk4 was found in OL with dysplasia, suggesting that cdk4 may be involved in the early event of carcinogenesis.     

Increased expression of Smad proteins,and in particular Smad3, in oral lichen planus compared to normal oral mucosa

J Oral Pathol Med (2010) 39 : 639–644 Backgound: Oral lichen planus (OLP) is a chronic inflammatory disease of the oral mucosa which the World Health Organisation (WHO) considers a premalignant condition. One step in malignant development is so called epithelial mesenchymal transition (EMT), a process whereby epithelial cells acquire mesenchymal characteristics. EMT occurs during embryogenesis and wound healing but also in some human diseases such as cancer and fibrosis. A factor known to induce EMT is transforming growth factor‐β (TGF‐β), which uses the Smad proteins as mediators for its signalling. TGF‐β is also often over‐expressed in squamous cell carcinoma of the head and neck (SCCHN). Methods: In the present study we mapped expression of Smad proteins in OLP lesions by immunohistochemistry, and compared to expression in normal and sensitive oral mucosa. The latter group of patients had developed SCCHN after shorter or longer periods of diffuse oral symptoms. The aim was to see if there were any signs of EMT related changes in the OLP lesions, as judged by changes in the TGF‐β pathway. Conclusion: Changes in the TGF‐β pathway related to EMT are seen in the very earliest stages of oral malignancy and become more severe as lesions progress.     

Matrix metalloproteinase 7 and perlecan in oral epithelial dysplasia and carcinoma in situ: an aid for histopathologic recognition of their cell proliferation centers

Background:  As one of the valuable tools for differential diagnoses of oral epithelial dysplasia, carcinoma in situ (CIS) and squamous cell carcinoma (SCC), we have proposed the immunohistochemistry for perlecan, a heparan sulfate proteoglycan (HSPG). As HSPGs have been shown to be extracellular docking molecules for matrix metalloproteinase (MMP) 7, our aim was to determine the expression mode of MMP-7 in these lesions for its possible diagnostic aid for oral borderline malignancies.
Methods:  Twenty cases each of moderate dysplasia, CIS, SCC, and normal/hyperplastic/mild dysplastic epithelia of the tongue and buccal mucosa were immunohistochemically examined for MMP-1, -2 and -7 in reference to their perlecan immunolocalization.
Results:  The expression of all three MMPs in the normal mucosal epithelium was restricted mainly to the parabasal layers. The most striking finding was strong expression of MMP-7 in epithelial dysplasia with a two-phase appearance: a clear demarcation of MMP-7-immunopositive (+) lower dysplastic/basaloid cells from non-positive upper keratinized cells. MMP-7+ cells were spread over the whole epithelial layer of CIS. In SCC, MMP-7 positivity was reduced from carcinoma cells but instead appeared in stromal cells. These expression profiles of MMP-7 resembled those of perlecan. MMP-1 and MMP-2 exhibited a similar but much weaker staining than MMP-7.
Conclusion:  These results suggest that the enhanced metabolism of perlecan associated with MMP-7 plays an important role in the cell proliferation of oral epithelia in their malignant transformation process, and that MMP-7 immunohistochemistry may be a valuable aid for identification of the cell proliferation center in oral CIS and dysplasia.     

Cytomorphometric analysis of squames obtained from normal oral mucosa and lesions of oral leukoplakia and squamous cell carcinoma

Ramaesh T, Mendis BRRN, Ratnatunga N, Thattil RQ: Cytomorphometric analysis of squames obtained from normal oral mucosa and lesions of oral leukoplakia and squamous cell carcinoma. J Oral Pathol Med 1998; 27: 83–6. © Munksgaard, 1998.
Cell and nuclear diameters (CD and ND) were measured in squames obtained from normal buccal mucosa and lesions of oral leukoplakia and squamous carcinoma (SCC) also from buccal mucosa. The study groups consisted of Group 1: normal buccal mucosa ( n = 40); Group 2: lesions with no epithelial dysplasia ( n = 58); Group 3: lesions with epithelial dysplasia ( n = 27); and Group 4: SCC lesions ( n = 51). The mean CD and ND values were: Group 1: 51.78 (± 0.11) and 8.36 (± 0.49); Group 2: 45.73 (± 0.16) and 8.31(± 0.68); Group 3: 41.32 (± 0.13) and 9.04 (± 0.46); Group 4: 38.58 (± 0.11) and 10.10 (± 0.56) urn, respectively. Correlation between the ND and CD was positive for Group 1 ( r = 0.78, P < 0.05) and Group 2 ( r = 0.33, P < 0.05). There were no significant correlations in Groups 3 and 4. ANOVA showed significant differences ( P < 0.05) for CD between all four groups. Except between Groups 1 and 2, the ND was significantly different ( P < 0.05) between all groups. The results indicate that ND and CD could possibly be sensitive parameters in the diagnosis of oral premalignant and malignant lesions.     

Expression of vascular endothelial growth factor (VEGF) in normal oral mucosa, oral dysplasia and oral squamous cell carcinoma

Vascular endothelial growth factor (VEGF) is a potent angiogenic cytokine implicated in tumour vasculogenesis. A significant increase in vascularity occurs during the transition from normal oral mucosa (NOM), through dysplasia, to squamous cell carcinoma (SCC). This study investigated the presence of VEGF in NOM, oral dysplasia and SCC. The correlation between VEGF expression and the grade of dysplasia or differentiation of SCC was also examined. Specimens consisting of NOM, oral dysplastic lesions and oral SCC were stained using standard immunohistochemistry methods to determine VEGF expression. Statistical analysis indicated an up-regulation of VEGF during the transition from NOM, through dysplasia to SCC. There was also a significant difference in expression according to differentiation of SCC, but not grade of dysplasia. As VEGF is a potent mediator of vascular development, these results suggest that VEGF may play an important role in the maintenance of a blood supply for developing pre-cancerous and invasive oral lesions.     

Nuclear fractal dimension in oral squamous cell carcinoma: a novel method for the evaluation of grading,staging, and survival

Fractal dimension (FD) in tissue specimens from patients with oral squamous cell carcinoma (OSCC) was evaluated. FD values in different stages of OSCC, and the correlations with clinicopathological variables and patient survival were investigated. Histological sections from OSCC and control non‐neoplastic mucosa specimens were stained with hematoxylin–eosin for pathological analysis and with Feulgen for nuclear evaluation. FD in OSCC groups vs. controls revealed statistically significant differences (P < 0.001). In addition, a progressive increase of FD from stage I and II lesions and stage III and IV lesions was observed, with statistically significant differences (P = 0.003). Moreover, different degrees of tumor differentiation showed a significant difference in the average nuclear FD values (P = 0.001). A relationship between FD and patients' survival was also detected with lower FD values associated to longer survival time and higher FD values with shorter survival time (P = 0.034). These data showed that FD significantly increased during OSCC progression. Thus, FD could represent a novel prognostic tool for OSCC, as FD values significantly correlated with patient survival. Fractal geometry could give insights into tumor morphology and could become an useful tool for analyzing irregular tumor growth patterns.     

Morphometric computer‐assisted image analysis of oral epithelial cells in normal epithelium and leukoplakia

J Oral Pathol Med (2010) 39 149–154 Background: There are very few studies documenting morphometric parameters of normal oral mucosa and leukoplakia. The present study was undertaken to establish the morphometric parameters of the parabasal and spinous cells of normal oral epithelium. Analysis of changes occurring in these cells in leukoplakia was also done. Methods: This study was conducted on tissue sections of clinically normal oral mucosa and leukoplakia. Morphometric analysis was done for parabasal and spinous cells. Statistical analysis was done using one way ANOVA and Mann–Whitney test. Results: Morphometric parameters were greater in the spinous cells than in parabasal cells in normal oral mucosa. Leukoplakia showed greater cellular and nuclear parameters than normal mucosa. Conclusion: Normal oral epithelium showed site‐wise difference in cell and nuclear measurements. Nuclear parameters showed a statistically significant change than cellular parameters in dysplasia. These changes were expressed in the earliest stage of transformation to dysplasia.     

单层上皮细胞角蛋白在口腔粘膜癌变过程中的表达

目的：探讨单层上皮细胞角蛋白ＣＫ１８和ＣＫ１９作为口腔癌前病变标志的可能性。方法：用ＬＳＡＢ免疫组化染色方法检测ＣＫ１８和ＣＫ１９在福尔马林固定,石蜡包埋的口腔正常粘膜,上皮单纯增生,轻度上皮导演增生,中度上皮异常增生,重度上皮异常增生和口腔鳞癌组织中的分布和表达强度,光镜观察染色切片,结果用秩和检验分析。     

Increase of mast cells and tumor angiogenesis in oral squamous cell carcinoma

BACKGROUND: Although mast cells (MCs) have been implicated in promoting angiogenesis in some malignant tumors, especially of the aerodigestive tract, little is known in oral squamous cell carcinoma (SCC). METHODS: A retrospective study was conducted to elaborate upon the correlation between MCs and tumor angiogenesis in 26 cases of oral SCC, six cases of oral pre-malignant dysplasia, 10 cases of oral hyperkeratosis, and six cases of normal oral mucosa by means of immunohistochemical technique. RESULTS: The MCs in all lesions and normal oral mucosa strongly expressed tryptase. The densities of MCs and microvessels appeared to increase with disease progression. The MC and microvascular counts were significantly higher in oral SCC than in hyperkeratosis and normal oral mucosa (P < 0.05). A significant correlation between MC and microvascular densities was observed in oral SCC (r = 0.5; P = 0.012). CONCLUSIONS: These findings suggest that MCs may upregulate tumor angiogenesis in oral SCC, perhaps via MC tryptase.     

口腔癌前病变细胞凋亡的原位观察与分析

目的　探讨口腔白斑、扁平苔藓的癌变机制。方法　通过原位末端转移酶标记法 ,观察分析 10例正常口腔黏膜上皮 ,18例扁平苔藓 ,2 3例白斑 ,2 2例鳞癌上皮组织凋亡状况。结果　除单纯上皮增生 ,非糜烂型扁平苔藓外 ,上皮 (轻、中、重 )异常增生 ,鳞癌及糜烂型扁平苔藓的凋亡指数均高于正常 ,差异有显著性。从上皮异常增生到鳞癌凋亡指数逐渐增高 ,糜烂型扁平苔藓的凋亡指数低于鳞癌 ,差异有显著性。结论　细胞凋亡参与白斑癌变的过程 ,在病变不同阶段作用不同。扁平苔藓的发病机制可能与细胞免疫诱导角朊细胞凋亡亢进有关     

Increase in placental glutathione S-transferase in human oral epithelial dysplastic lesions and squamous cell carcinomas

This study investigated the immunohistochemical expression of human placental glutathione S-transferase (GST-φ) in the epithelium of oral premalignant and malignant lesions. Epithelial lining of normal oral mucosa, hyperplastic lesions and oral epithelium exhibiting mild dysplasia showed weak to moderate GST-φ staining. Moderate epithelial dysplasia revealed an increased antibody content while severe dysplasia. carcinoma- in-situ (CIS) and squamous cell carcinoma (SCC) demonstrated markedly increased antibody binding. The GST-φ staining was evident mainly in the cytoplasm. Severe dysplasia. CIS and SCC were also characterized by areas of cells with intensive nuclear GST-φ staining. These findings support the hypothesis that GST-φ plays a role in human oral carcinogenesis and may be used as a tumor marker for human oral premalignant and malignant lesions.     

Outcomes of oral squamous cell carcinoma arising from oral epithelial dysplasia: rationale for monitoring premalignant oral lesions in a multidisciplinary clinic

Surveillance of oral epithelial dysplasia results in a number of newly diagnosed cases of oral squamous cell carcinoma (SCC). The clinical stage of oral SCC at diagnosis influences the magnitude of treatment required and the prognosis. We aimed to document the stage, treatment, and outcome of oral SCC that arose in patients who were being monitored for oral epithelial dysplasia in a dedicated multidisciplinary clinic. Those with histologically diagnosed lesions were enrolled on an ethically approved protocol and molecular biomarker study. Details of clinical and pathological TNM, operation, radiotherapy, recurrence, second primary tumour, and prognosis, were recorded in patients whose lesions underwent malignant transformation. Of the 91 patients reviewed (median follow-up 48 months, IQR 18-96), 23 (25%) had malignant transformation. All were presented to the multidisciplinary team with stage 1 disease (cT1N0M0). Of these, 21 were initially treated by wide local excision, 2 required resection of tumour and reconstruction, and 2 required adjuvant radiotherapy. At follow-up 3 had local recurrence, one had regional recurrence, one had metachronous lung cancer, and 5 had second primary oral SCC. There were further diagnoses of oral dysplasia in 5 during follow-up, and it is estimated that 76% of patients will have one or other event in 5 years. Disease-specific survival was 100% and overall survival was 96% (22/23). Median follow-up after diagnosis of oral SCC was 24 months (IQR 11-58). Specialist monitoring of oral epithelial dysplasia by a multidisciplinary team allows oral SCC to be detected at an early stage, and enables largely curative treatment with simple and usually minor surgical intervention. The high incidence of second primary oral SCC in high-risk patients with oral epithelial dysplasia further supports intensive targeted surveillance in this group.     

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.     

The relationship between E-cadherin expression, clinical stage and tumour differentiation in oral squamous cell carcinoma

OBJECTIVES: To evaluate the expression of E-cadherin, a calcium-dependent cell adhesion molecule, in a retrospective analysis of paraffin embedded tissue specimens of oral squamous cell carcinoma and relationship with the clinical TNM stage and histochemical differentiation. DESIGN: Paraffin embedded tissue sections of normal oral mucosa ( n = 6), oral squamous cell carcinoma (SCC, n = 18) and metastatic lymph nodes ( n = 2) were immunostained by a three-stage streptoavidin-biotin immunoperoxidase method using monoclonal antibody. The TNM staging and histochemical grading were done according to the standard criteria.
RESULTS: Normal oral epithelium showed a strongly positive pericellular distribution of E-cadherin in basal, parabasal and spinous layers and no staining was observed in the parakeratinized and cornified layerS. In well differentiated SCCs, the centrally located cells in tumour islands showed no staining, but peripheral basally located tumour cells showed positive staining. Poorly differentiated SCCs were devoid of staining. In moderately differentiated SCCs, the staining pattern was found to be one of the following three types: (1) a pattern similar to that of well differentiated SCC; (2) central cells of tumour aggregates were reactive but peripheral cells showed weak to negative reaction; and (3) all cells showed a negative reaction, resembling the poorly differentiated SCC.Fischer exact test showed a statistically significant correlation with loss of E-cadherin and grades of tumour differentiation as well as an advancing T and N stage.
CONCLUSION: The loss of E-cadherin may correlate with advancing T and N stages of the tumour and a poor tumour cell differentiation in oral squamous cell carcinomas.     

Expression of p16 in oral cancer and premalignant lesions

Background:  Expression of p16 has been proposed as a marker for malignant transformation. This study aimed to evaluate p16 expression in oral squamous cell carcinoma (OSCC) and premalignant lesions including oral leukoplakia (OL) with and without dysplasia.
Methods:  Expression of p16 was investigated in 56 samples including OSCC, OL with and without dysplasia, and normal oral mucosa. Expression of p16 was identified by immunohistochemistry, using the CINtecTM p16INK4a Histology Kit. Both nuclear and/or cytoplasmic staining of the keratinocytes were considered to be positive and the percentage of positive cells was calculated.
Results:  Expression of p16 was detected in 3/16 (18.75%) cases of OSCC, in 4/15 (26.7%) cases of OL without dysplasia, and in none of OL with dysplasia and normal mucosa. No significant differences in p16 expression prevalence were found among OSCC, OL with and without dysplasia and normal mucosa. The percentages of positive cells in OSCC and OL without dysplasia were 0.89 and 0.17, respectively. No significant difference in the percentage of positive keratinocytes was found.
Conclusion:  As a marker, p16 is not reliable for oral mucosal dysplasia and malignant transformation.     

Enhancement of calcyclin gene RNA expression in squamous cell carcinoma of the oral mucosa, but not in benign lesions

Oral cancer is a neoplasm with some known causes. Proliferation genes are significant among its few pathogenetic and prognostic factors. Calcyclin is a cell-cycle-related gene, the function of which is still unclear. Its expression and that of Haras and histone-H3 have been investigated in an assessment of their pathogenetic role in squamous cell carcinoma. RNA extracted from the pathological and normal mucosa of patients with squamous cell carcinoma (SCC) and benign lesions was reverse transcribed and amplified by the polymerase chain reaction (PCR). The expression of all three genes in the pathological mucosa was enhanced in SCC only. This suggests that they may be involved in its pathogenesis and provides another parameter for the differentiation of malignant and benign lesions.