Maspin, p53, p63, and Ki-67 in epithelial lesions of the tongue: from hyperplasia through dysplasia to carcinoma

Biomarkers of malignant transformation in oral leukoplakia: from bench to bedside

Oral leukoplakia is a common precursor lesion of oral squamous cell carcinoma, which indicates a high potential of malignancy. The malignant transformation of oral leukoplakia seriously affects patient survival and quality of life; however, it is difficult to identify oral leukoplakia patients who will develop carcinoma because no biomarker exists to predict malignant transformation for effective clinical management. As a major problem in the field of head and neck pathologies, it is imperative to identify biomarkers of malignant transformation in oral leukoplakia. In this review, we discuss the potential biomarkers of malignant transformation reported in the literature and explore the translational probabilities from bench to bedside. Although no single biomarker has yet been applied in the clinical setting, profiling for genomic instability might be a promising adjunct.

Immunohistochemical evaluation of p63 and cyclin D1 in oral squamous cell carcinoma and leukoplakia

Objectives

There are only a limited number of studies on cyclin D1 and p63 expression in oral squamous cell carcinoma (OSCC) and leukoplakia. This study compared cyclin D1 and p63 expression in leukoplakia and OSCC to investigate the possible correlation of both markers with grade of dysplasia and histological grade of OSCC.

Materials and Methods

The study included a total of 60 cases, of which 30 were diagnosed with OSCC and 30 with leukoplakia, that were evaluated immunohistochemically for p63 and cyclin D1 expression. Protein expression was correlated based on grades of dysplasia and OSCC.

Results

Out of 30 cases of OSCC, 23 cases (76.7%) were cyclin D1 positive and 30 cases (100%) were p63 positive. Out of 30 cases of leukoplakia, 21 cases (70.0%) were cyclin D1 positive and 30 (100%) were p63 positive (P<0.05).

Conclusion

The overall expression of cyclin D1 and p63 correlated with tumor differentiation, and increases were correlated with poor histological grades, from well-differentiated to poorly-differentiated SCC. Increased cyclin D1 and p63 expression was associated with the severity of leukoplakia. Based on these results cyclin D1 and p63 products can be a useful tool for improved leukoplakia prognosis.

Immunohistochemical evaluation of p63 and cyclin D1 in oral squamous cell carcinoma and leukoplakia

Objectives

There are only a limited number of studies on cyclin D1 and p63 expression in oral squamous cell carcinoma (OSCC) and leukoplakia. This study compared cyclin D1 and p63 expression in leukoplakia and OSCC to investigate the possible correlation of both markers with grade of dysplasia and histological grade of OSCC.

Materials and Methods

The study included a total of 60 cases, of which 30 were diagnosed with OSCC and 30 with leukoplakia, that were evaluated immunohistochemically for p63 and cyclin D1 expression. Protein expression was correlated based on grades of dysplasia and OSCC.

Results

Out of 30 cases of OSCC, 23 cases (76.7%) were cyclin D1 positive and 30 cases (100%) were p63 positive. Out of 30 cases of leukoplakia, 21 cases (70.0%) were cyclin D1 positive and 30 (100%) were p63 positive (P<0.05).

Conclusion

The overall expression of cyclin D1 and p63 correlated with tumor differentiation, and increases were correlated with poor histological grades, from well-differentiated to poorly-differentiated SCC. Increased cyclin D1 and p63 expression was associated with the severity of leukoplakia. Based on these results cyclin D1 and p63 products can be a useful tool for improved leukoplakia prognosis.

Can immunohistochemistry serve as an alternative to subjective histopathological diagnosis of oral epithelial dysplasia?

Many attempts have been made to identify objective molecular biomarkers to diagnose and prognosticate oral epithelial dysplasia (OED) because histopathological interpretation is subjective and lacks sensitivity. The majority of these efforts describe changes in gene expression at protein level in OED as determined by immunohistochemistry (IHC). However, the literature on these putative markers of oral cancer progression is vast and varied. The main purpose of this article is to review current knowledge on biomarkers of protein expression for OED by IHC approaches. We further discuss these findings in terms of the proposed essential hallmarks of cancer cells to better understand their role in oral oncogenesis.

Expression of the tumour-suppressor maspin in temporal bone carcinoma

AIMS

Although it accounts for fewer than 0.2% of all head and neck tumours, temporal bone squamous cell carcinoma (SCC) is an aggressive malignancy with a poor prognosis in advanced cases. Novel therapeutic strategies should be developed focusing on specific targeted therapies. Maspin is a serpin showing tumour-suppressing activity which has therapeutic potential. The present study is the first to investigate maspin expression in temporal bone SCCs, using a series of 29 cases.

METHODS AND RESULTS

Cytoplasmic maspin expression was significantly higher in the group of patients whose SCC did not recur than in the group experiencing recurrences (P = 0.029), and in G1-G2 SCCs than in G3 cases (P = 0.001). cT correlated with recurrence rate (P = 0.05), disease-free survival (DFS) (P = 0.008) and disease-specific survival (DSS) (P = 0.0043), and pT and pathological regional lymph node status correlated with recurrence rate (P = 0.008 and P = 0.03, respectively), DFS (P = 0.017 and P = 0.0049, respectively) and DSS (P = 0.008 and P = 0.0009, respectively).

CONCLUSIONS

Although further studies using larger series are required, our preliminary findings suggest that cytoplasmic maspin expression has promise as a prognostic indicator of disease recurrence in temporal bone SCC, and that reactivating maspin functions in association with apoptosis-inducing or anti-angiogenic chemotherapeutic agents might be an important goal in the treatment of temporal bone SCC.

High expression of p63 is correlated to poor prognosis in squamous cell carcinoma of the tongue

BACKGROUND

p63 proteins are important in formation of the oral mucosa. Normal oral mucosa shows a balance between the six protein isoforms, whereas an imbalance between them is seen in squamous cell carcinomas (SCC). There is controversy over the clinical impact of p63 in SCC, which may relate to different expression in different areas. In addition, p63 isoforms can act as p53-like molecules (TAp63) or can inhibit p53 functions (ΔNp63) and expression of these isoforms varies in different tumours. Here, we chose to concentrate on the most common intra-oral sub-site, SCC of the mobile tongue.

METHODS

Total p63, ΔNp63 and TAp63 were analysed separately using immunohistochemistry. The percentage of cells and intensity of expression of different isoforms of p63 was evaluated using a quick score method and correlated with clinical data in a group of 87 patients with tongue SCC.

RESULTS

All tumours expressed p63 in at least 60% of the cells when using two different antibodies detecting all 6 isoforms. p63 expression correlated significantly with 2-year survival (P = 0.018), with fewer patients surviving 2 years if their tumours expressed p63 with strong intensity in at least 80% of the cells (quick score 18). Looking at 5-year survival, this was even more emphasized. ΔNp63 was expressed in all tumours, whereas expression of TAp63 was seen only in 59/87 patients, usually at very low levels.

CONCLUSIONS

Based on the present data, we recommend using expression of p63 as an additional factor contributing prognostic information in analysis of SCC in the tongue.

Langerhans cells and T cells sense cell dysplasia in oral leukoplakias and oral squamous cell carcinomas--evidence for immunosurveillance

Leukoplakias (LPLs) are lesions in the oral mucosa that may develop into oral squamous cell carcinoma (OSCC). The objective of this study was to assess presence and distribution of dendritic Langerhans cells (LCs) and T cells in patients with LPLs with or without cell dysplasia and in oral squamous cell carcinoma (OSCC). Biopsy specimens from patients with leukoplakias (LPLs) with or without dysplasia and oral squamous cell carcinoma (OSCC) were immunostained with antibodies against CD1a, Langerin, CD3, CD4, CD8 and Ki67, followed by quantitative analysis. Analyses of epithelium and connective tissue revealed a significantly higher number of CD1a + LCs in LPLs with dysplasia compared with LPLs without dysplasia. Presence of Langerin + LCs in epithelium did not differ significantly between LPLs either with or without dysplasia and OSCC. T cells were found in significantly increased numbers in LPLs with dysplasia and OSCC. The number of CD4+ cells did not differ significantly between LPLs with and without dysplasia, but a significant increase was detected when comparing LPLs with dysplasia with OSCC. CD8+ cells were significantly more abundant in OSCC and LPLs with dysplasia compared with LPLs without dysplasia. Proliferating cells (Ki67+) were significantly more abundant in OSCC compared to LPLs with dysplasia. Confocal laser scanning microscopy revealed colocalization of LCs and T cells in LPLs with dysplasia and in OSCC. LCs and T cells are more numerous in tissue compartments with dysplastic epithelial cells and dramatically increase in OSCC. This indicates an ongoing immune response against cells with dysplasia.

Differences in the expression of five senescence markers in oral cancer, oral leukoplakia and control samples in humans

Oncogene-induced senescence (OIS) may be a response to oncogenic activation, acting as a natural barrier against carcinogenesis at a premalignant stage. Thus, numerous cells in premalignant lesions enter senescence, but none or few in malignant tumours. This event could be due to the loss of senescence pathway effectors, including p16 (INK4a)-pRb or ARF-p53. The aim of this study was to characterize and compare the expression of certain senescent markers between oral precancer and cancer tissue samples. The expression of cyclin D1, Rb, maspin, p53 and mouse double minute 2 (MDM2) was analyzed in 20 paraffin-embedded tissue samples of normal oral mucosa (NOM), 14 samples of oral leukoplakia without dysplasia (OLD-), 11 samples of leukoplakia with dysplasia (OLD+) and 15 samples of oral squamous cell carcinoma (OSCC) by immunohistochemistry in tissue arrays. The expression of p16-pRb pathway markers, cyclin D1, maspin and Rb, was more frequent in OLD+ samples than in OSCC samples, although a statistical significance was only observed for maspin (P=0.036). Cyclin D1 expression was also significantly more frequent in OLD- samples vs. NOM samples. For the ARF-p53 pathway, the expression of p53 and MDM2 was significantly more frequent in the OLD- samples compared to in the NOM ones. These findings may indicate a role for cellular senescence in oral carcinogenesis, considering maspin as a reliable senescence marker and prognostic factor in oral premalignant lesions.

Biomarkers of oral premalignant epithelial lesions for clinical application

Oral cancer is the sixth most common form of cancer worldwide, and the majority of cases occur in India and Southeast Asia. Its major risk factors in the western world include smoking and drinking alcohol, whereas in Asia, it is primarily caused by tobacco/areca nut/betel leaf chewing and/or human papillomavirus (HPV) infections. Little is known about this type of cancer despite recent advances in cancer biology. The generally asymptomatic nature of the early oral lesions causes them to remain undetected in many cases. Thus, the disease progresses substantially before the patients seek treatment and is a major contributing factor to the severity of this disease. Therefore, there is a great need to create awareness for its prevention and early diagnosis. The application of advanced molecular biological and biochemical methodologies to elucidate its biomarkers may aid in early detection; however, much more work must be done for this information to be effectively applied in the clinical setting. This review focuses on the need for systematic diagnoses in the early detection of oral cancer using molecular and biochemical approaches, thereby reducing the number of advanced cases in the chewing tobacco-dominated oral cancer population.

Genetics/epigenetics of oral premalignancy: current status and future research

Squamous cell carcinoma (SCC) of the oral and oropharyngeal region is the sixth most common malignancy in the world today. Despite numerous advances in treatment, long-term survival from this disease remains poor. Early detection can decrease both morbidity and mortality associated with this neoplasm. However, screening for potentially malignant disease is typically confounded by difficulty in discriminating between reactive/inflammatory lesions vs those lesions that are premalignant in nature. Furthermore, the histologic diagnosis of dysplasia can be subjective and is thus prone to a considerable range of interpretation. Similarly, no definitive, validated criteria exist for predicting which dysplastic lesions are most likely to progress to cancer over time. Given this state of science, the presence of dysplasia can only be used to indicate that an oral lesion may have an increased risk of malignant transformation. Molecular biomarkers capable of identifying the subset of lesions likely to progress to cancer are required to eliminate this clinical diagnostic dilemma. The purpose of this review is to assess the current state of knowledge regarding genetic/epigenetic alterations observed in oral mucosal premalignancy. In addition, recommendations for future research studies directed at defining the predictive capacity of specific biomarkers in this modeling are presented.

Is maspin immunolocalization a tool to differentiate central low-grade mucoepidermoid carcinoma from glandular odontogenic cyst?

Mucoepidermoid carcinoma (MEC) of the salivary glands has a low-grade variant (LGMEC), which may be found within the jawbones. LGMEC shares a number of histopathological similarities with glandular odontogenic cysts (GOC) of the jawbones. Maspin has been identified in several benign and malignant salivary gland neoplasms. We investigated the immunolocalization of maspin in LGMEC and GOC and evaluated its potential to distinguish between these two entities. Cases of LGMEC (n=6), GOC (n=8) and various odontogenic cysts with marked mucous metaplasia (OCMM, n=7), which served as controls, were immunohistochemically labeled for the binding of an antibody directed against maspin. Immunomorphometry was performed separately for maspin-immunopositive epithelial cells and epithelial-mucous cells in either their nuclear or cytoplasmic compartments. Results were presented as the volume fraction (Vv) of each element. The Vv of the maspin-immunopositive epithelial-mucous cytoplasm and nuclei was significantly higher in LGMEC than in GOC and OCMM (p<0.001 and p=0.026, respectively). In the epithelial cells, no significant differences were observed among the lesions (p>0.05). It is suggested that the high levels of maspin in the epithelial-mucous cells (in both cytoplasm and nuclei) in LGMEC may serve as a tool to distinguish it from GOC. This may be useful especially in equivocal cases and in small incisional biopsy samples.