Expression of podoplanin and ABCG2 in oral erythroplakia correlate with oral cancer development

The role of podoplanin inhibitors in controlling oral cancer progression

OBJECTIVE

In this article, we review the current studies on the role of podoplanin in oral cancer and the potential application of podoplanin inhibitors as a therapeutic agent for oral cancer.

DESIGN

The narrative review approach was conducted, providing a comprehensive perspective of related literature. Publications addressing podoplanin and its inhibitors in the context of oral cancer were retrieved from PubMed and Scopus databases.

RESULTS

Podoplanin has emerged as a biomarker and therapeutic agent for oral cancer. Numerous studies have reported high podoplanin expression in oral cancer and pre-cancerous lesions compared to normal cells. A specific inhibitor targeting podoplanin may have the potential to prevent oral carcinogenesis via interfering with the pathway of cancerous cells involved in cell proliferation and metastasis. Antibodies, chimeric antigen receptor (CAR)-T cells, cancer-specific mAb (CasMab), synthetic molecules, and lectins are among the materials used as anticancer agents targeting podoplanin. Plant-derived lectins appear to demonstrate a unique advantage against alternative candidates.

CONCLUSIONS

The use of podoplanin inhibitors in place of existing therapeutic approaches could be a promising and novel approach to the prevention and treatment of oral cancer. Nevertheless, further research is required to investigate the practical application of such inhibitors.

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.

Podoplanin Expression in Odontogenic Keratocysts Associated or not Associated With Nevoid Basal Cell Carcinoma Syndrome

BACKGROUND

Podoplanin is a transmembrane glycoprotein expressed on various normal or neoplastic cells. Some studies have shown that podoplanin promotes the migration and invasion of tumor cells. This study evaluated a podoplanin expression in Odontogenic Keratocysts (OKs) associated or not associated with Nevoid Basal Cell Carcinoma Syndrome (NBCCS) and in Orthokeratinized Odontogenic Cysts (OOCs).

MATERIALS AND METHODS

A total of 50 lesions were obtained in this study, 28 OKs, 18 OKs associated with NBCCS, and 4 OOCs. Immunohistochemical expression of podoplanin in epithelial cells was evaluated using the following score: (a) intensity of immunostaining: (0: absent, 1: weak, 2: moderate, 3: strong, and 4: very strong) and (b) number of positively cells (0: 0%, 1: <25%, 2: 25% to 50%, 3: 50% to 75%, and 4: >75%). The final score was determined by adding the scores of a and b and ranged from 0 to 8 (0: absent, 1 to 4: weak, and 5 to 8: strong).

RESULTS

Podoplanin expression was significantly stronger in the basal layer OKs and NBCCS lesions. Further, podoplanin expression was the highest in the suprabasal layer of NBCCS lesions, followed by the suprabasal layers of OK and OOC lesions.

CONCLUSIONS

Podoplanin expression is different in lesions of different biological behaviors. Podoplanin seems to play a role in cell proliferation and migration.

HPV+ve/-ve oral-tongue cancer stem cells: A potential target for relapse-free therapy

The tongue squamous cell carcinoma (TSCC) is a highly prevalent head and neck cancer often associated with tobacco and/or alcohol abuse or high-risk human papillomavirus (HR-HPV) infection. HPV positive TSCCs present a unique mechanism of tumorigenesis as compared to tobacco and alcohol-induced TSCCs and show a better prognosis when treated. The poor prognosis and/or recurrence of TSCC is due to presence of a small subpopulation of tumor-initiating tongue cancer stem cells (TCSCs) that are intrinsically resistant to conventional chemoradio-therapies enabling cancer to relapse. Therefore, targeting TCSCs may provide efficient therapeutic strategy for relapse-free survival of TSCC patients. Indeed, the development of new TCSC targeting therapeutic approaches for the successful elimination of HPV+ve/-ve TCSCs could be achieved either by targeting the self-renewal pathways, epithelial mesenchymal transition, vascular niche, nanoparticles-based therapy, induction of differentiation, chemoradio-sensitization of TCSCs or TCSC-derived exosome-based drug delivery and inhibition of HPV oncogenes or by regulating epigenetic pathways. In this review, we have discussed all these potential approaches and highlighted several important signaling pathways/networks involved in the formation and maintenance of TCSCs, which are targetable as novel therapeutic targets to sensitize/eliminate TCSCs and to improve survival of TSCC patients.

Expression of CD44, CD44v9, ABCG2, CD24, Bmi-1 and ALDH1 in stage I and II oral squamous cell carcinoma and their association with clinicopathological factors

Cancer stem cells (CSCs) exhibit self-replication, self-differentiation, drug resistance and immune evasion activities. In recent years CSCs have become increasingly important for the treatment of malignant tumors. CSCs express specific markers, including cluster of differentiation (CD)44, CD44 variant 9 (CD44v9), ATP-binding cassette sub-family G member 2 (ABCG2), CD24, B lymphoma Mo-MLV insertion region 1 homolog (BMI-1) and aldehyde dehydrogenase 1 (ALDH1). However, the prognostic value of their expression in patients with oral squamous cell carcinoma (OSCC) are not well known. The present study evaluated these markers in stage I and II patients with OSCC and examined the association between T classification, histological differentiation, classification of invasion mode, lymph node metastasis and disease-free survival rate. Tissue specimens were obtained from 70 patients with stage I or II OSCC following either surgery or biopsy. Immunohistochemistry was performed and positive staining was defiend as 10% positive cells. CD44 and CD44v9 expressions were strongly detected in all OSCC tissues compared with normal epithelial cells. A total of 22 (31.4%) cases expressed ABCG2 and there was a significant association between ABCG2 expression and invasion. A total of 41 cases (59.0%) expressed CD24 and there was a significant association between CD24 expression and invasion. A total of 33 cases (47.1%) expressed BMI-1 and there was a significant association between BMI-1 expression and the disease-free survival rate. A total of 18 cases (25.7%) expressed ALDH1. Although there was no association between ALDH1 expression and T classification, there were significant associations between ALDH1 expression and histological differentiation, invasion mode, metastasis and the disease-free survival rate. Multivariate analysis revealed that ALDH1 expression was the only prognostic factor for disease-free survival rate. The results of the present study suggest that the positivity of ALDH1 detected in patients with OSCC correlates with the number of cells undergoing epithelial mesenchymal transition and metastasis. These findings indicated that the expression of ALDH1 may be an effective prognostic marker indicating the survival of patients with stage I and II OSCC.

Podoplanin emerges as a functionally relevant oral cancer biomarker and therapeutic target

Oral cancer has become one of the most aggressive types of cancer, killing 140,000 people worldwide every year. Current treatments for oral cancer include surgery and radiation therapies. These procedures can be very effective; however, they can also drastically decrease the quality of life for survivors. New chemotherapeutic treatments are needed to more effectively combat oral cancer. The transmembrane receptor podoplanin (PDPN) has emerged as a functionally relevant oral cancer biomarker and chemotherapeutic target. PDPN expression promotes tumor cell migration leading to oral cancer invasion and metastasis. Here, we describe the role of PDPN in oral squamous cell carcinoma progression, and how it may be exploited to prevent and treat oral cancer.

A Real-Time Near-Infrared Fluorescence Imaging Method for the Detection of Oral Cancers in Mice Using an Indocyanine Green-Labeled Podoplanin Antibody

Podoplanin is distinctively overexpressed in oral squamous cell carcinoma than oral benign neoplasms and plays a crucial role in the pathogenesis and metastasis of oral squamous cell carcinoma but its diagnostic application is quite limited. Here, we report a new near-infrared fluorescence imaging method using an indocyanine green (ICG)-labeled anti-podoplanin antibody and a desktop/a handheld ICG detection device for the visualization of oral squamous cell carcinoma-xenografted tumors in nude mice. Both near-infrared imaging methods using a desktop (in vivo imaging system: IVIS) and a handheld device (photodynamic eye: PDE) successfully detected oral squamous cell carcinoma tumors in nude mice in a podoplanin expression-dependent manner with comparable sensitivity. Of these 2 devices, only near-infrared imaging methods using a handheld device visualized oral squamous cell carcinoma xenografts in mice in real time. Furthermore, near-infrared imaging methods using the handheld device (PDE) could detect smaller podoplanin-positive oral squamous cell carcinoma tumors than a non-near-infrared, autofluorescence-based imaging method. Based on these results, a near-infrared imaging method using an ICG-labeled anti-podoplanin antibody and a handheld detection device (PDE) allows the sensitive, semiquantitative, and real-time imaging of oral squamous cell carcinoma tumors and therefore represents a useful tool for the detection and subsequent monitoring of malignant oral neoplasms in both preclinical and some clinical settings.

Podoplanin Expression Is Correlated With the Progression of Chronic Discoid Lupus Erythematosus to Lip Squamous Cell Carcinoma

Chronic lip discoid lupus erythematosus (DLE) is a potentially malignant disorder that can develop into lip squamous cell carcinoma (LSCC). Podoplanin is a specific marker for lymphatic endothelial cells and plays a role in cancer progression. The objective of this study was to determine the immunoexpression of podoplanin in samples of patients with DLE and its correlation with the risk of progression to LSCC. In a retrospective study, podoplanin expression was determined using immunohistochemistry in samples from 52 patients with DLE, including 44 patients with untransformed DLE and 8 patients with malignant transformed DLE. Ten samples of normal oral mucosa and 10 samples of LSCC were used as normal and cancer controls, respectively. The results showed that podoplanin expression was observed in 12 of 44 (27.3%) patients with untransformed DLE and in 7 of 8 (87.5%) patients with transformed DLE (P = .002). Podoplanin was not expressed in normal oral mucosa, but it was overexpressed in all of the 10 patients with LSCC. Regression analysis revealed that podoplanin expression was significantly associated with an 18.67-fold increase in the risk of malignant progression (95% confidence interval = 2.07-168.10; P = .009). In summary, podoplanin expression is significantly associated with malignant transformation of DLE into LSCC. Thus, podoplanin expression may identify a subgroup with a high risk of malignant progression of DLE.

Prognostic significance of CD44v6, p63, podoplanin and MMP-9 in oral squamous cell carcinomas

OBJECTIVES

To analyse the expression of the CD44v6, p63, podoplanin and MMP-9, and their prognostic significance in patients with oral squamous cell carcinomas (OSCC).

MATERIAL AND METHODS

Immunohistochemistry technique was performed on 60 OSCC for detection of CD44v6, p63, podoplanin and MMP-9 proteins. Extent and intensity of staining were evaluated in tumour cells and were compared with patients' clinical-pathological characteristics and survival.

RESULTS

CD44v6 expression was detected at the membrane of tumour cells of 94% cases. Nuclear expression of p63 protein was present in 96.5%. Podoplanin was observed at the membrane of tumour cells of 94% cases. MMP-9 was found in the cytoplasm of tumour cells in 83.7% cases. A high level of expression (67%-89%) in all four proteins was noted. Podoplanin was associated with the expression of MMP-9 (P = 0.010) and both were associated with lymph node metastasis (P = 0.011 and P = 0.018, respectively). Co-expression of podoplanin/MMP-9 was an adverse independent prognostic factor for cancer-specific survival (P = 0.008) and recurrence-free survival (P = 0.042).

CONCLUSION

Podoplanin and MMP-9 together could contribute to tumour progression and dissemination of OSCC. Their combined overexpression showed an adverse effect on survival, suggesting that they could be regarded as important prognostic biomarkers in OSCC.

Evaluation of Podoplanin in Oral Leukoplakia and Oral Squamous Cell Carcinoma

Background. Recent studies have demonstrated that podoplanin was expressed in some dysplastic lesions adjacent to primary oral cancers suggesting that podoplanin expression may occur in early oral tumorigenesis and lymphangiogenesis and therefore is related to tumor growth. The purpose of this study is to determine the role of podoplanin as a biomarker for cancer risk assessment in oral leukoplakia and correlation of podoplanin expression with grades of oral squamous cell carcinoma (OSCC). Materials and Methods. In the present retrospective study, podoplanin expression was investigated immunohistochemically in 40 patients each of oral leukoplakia and OSCC. The scores were analyzed statistically using one-way ANOVA test followed by Tukey HSD. Results. By applying one-way ANOVA test, there was a highly significant increase of the podoplanin expression from mild to severe dysplasia and from well to poorly differentiated OSCC (P < 0.01). Statistically highly significant difference was present between scores of mild to moderate dysplasia, moderate to severe dysplasia, well to poorly differentiated OSCC, and moderately to poorly differentiated OSCC (Tukey HSD test, P < 0.01). Conclusion. Podoplanin can be used as a biomarker for early oral tumorigenesis and for malignant transformation risk assessment of premalignant lesions and as a tumor progression biomarker for advanced grades of OSCC.

Precancerous lesions of oral mucosa

Precancerous lesions of oral mucosa, known as potentially malignant disorders in recent years, are consists of a group of diseases, which should be diagnosed in the early stage. Oral leukoplakia, oral submucous fibrosis, and oral erythroplakia are the most common oral mucosal diseases that have a very high malignant transformation rate. Oral lichen planus is one of the potentially malignant disorders that may be seen in six different subtypes including papular, reticular, plaque-like, atrophic, erosive, and bullous type, clinically. Atrophic and erosive subtypes have the greater increased malignant transformation risk compared to another subtypes. Although there are various etiological studies, the etiology of almost all these diseases is not fully understood. Geographically, etiologic factors may vary. The most frequently reported possible factors are tobacco use, alcohol drinking, chewing of betel quid containing areca nut, and solar rays. Early diagnosis is very important and can be lifesaving, because in late stages, they may be progressed to severe dysplasia and even carcinoma in situ and/or squamous cell carcinoma. For most diseases, treatment results are not satisfactory in spite of miscellaneous therapies. While at the forefront of surgical intervention, topical and systemic treatment alternatives such as corticosteroids, calcineurin inhibitors, and retinoids are widely used.

Potentially malignant disorders of the oral cavity: current practice and future directions in the clinic and laboratory

Despite commendable progress in the prevention, detection, and treatment of a wide variety of solid tumor types, oral squamous cell carcinoma (OSCC) remains a significant health burden across the globe. OSCC carcinogenesis involves accumulation of genetic alterations that coincide with the multistep malignant transformation of normal oral epithelium. OSCC is often first diagnosed at late stages of the disease (advanced regional disease and/or metastasis). Delayed diagnosis precludes successful treatment and favorable outcomes. In clinical practice, opportunities exist to identify patients with oral potentially malignant disorders (OPMDs), which precede the development of cancer. This review addresses the current status of laboratory and clinical research on OPMDs, with emphasis on leukoplakia and erythroplakia. OSF is also presented, though there is a paucity of published studies on this disorder. We focus on findings that could translate into earlier diagnosis and more efficacious treatment of those lesions with significant malignant potential. We explore how markers of OPMD malignant transformation might be implemented into current diagnostic practice to help clinicians objectively stratify patients into treatment/follow-up groups according to relative risk. We provide an overview of recently concluded and ongoing OPMD chemoprevention trials. We describe laboratory OPMD models that can be used to not only to reveal the genetic and molecular intricacies of oral cancer but also to develop novel screening methods and therapeutic approaches. Finally, we call for targeted screening programs of at-risk populations in order to facilitate diagnosis and treatment of OPMD and early OSCC.

Cancer stem cell markers in head and neck squamous cell carcinoma

Head and neck squamous cell carcinoma (HNSCC) is one of the world's top ten most common cancers. Current survival rates are poor with only 50% of patients expected to survive five years after diagnosis. The poor survival rate of HNSCC is partly attributable to the tendency for diagnosis at the late stage of the disease. One of the reasons for treatment failure is thought to be related to the presence of a subpopulation of cells within the tumour called cancer stem cells (CSCs). CSCs display stem cell-like characteristics that impart resistance to conventional treatment modalities and promote tumour initiation, progression, and metastasis. Specific markers for this population have been investigated in the hope of developing a deeper understanding of their role in the pathogenesis of HNSCC and elucidating novel therapeutic strategies.