An immunohistochemical evaluation of podoplanin expression in oral leukoplakia and oral squamous cell carcinoma to explore its potential to be used as a predictor for malignant transformation

Podoplanin could be a predictive biomarker of the risk of patients with oral leukoplakia to develop oral cancer: A systematic review and meta-analysis

OBJECTIVES

The aim of this study is to identify and analyze the existing literature on the utility of podoplanin to predict the risk of malignancy development (MD) in patients previously diagnosed with oral leukoplakia (OL).

METHODS

A systematic review and meta-analysis (SRMA) was performed though a search strategy using several electronic databases and a combination of keywords related to podoplanin and MD of OL, until 15 May, 2022 (PROSPERO CRD42022329326). Evaluation of the risk of bias (ROB) was performed using the Quality in Prognosis Studies Tool. The meta-analyses were estimated using fixed-effect models.

RESULTS

From 421 articles, 6 studies were finally included, that enrolled 546 patients with OL, of whom 125 presented with an oral cancer during follow-up (32 to 90 months). Some limitations regarding the ROB were identified mostly related to small sample sizes, short follow-up times, lack of information on covariables in the included studies and lack of accuracy (including sensitivity and specificity). Meta-analysis of 6 studies reveal that high expression of podoplanin carries a pooled hazard ratio (HR) of 3.72 (95% CI, 2.40-5.76; p < 0.00001) for MD without statistical heterogeneity (I2  = 0%, p = 0.53).

CONCLUSION

The results of this SRMA support the role of podoplanin immunohistochemical expression as a potential predictive biomarker to assess the risk of malignancy development in oral leukoplakia.

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.

Evaluation of immuno-histochemical markers in oral squamous cell carcinoma

Evaluation of immuno-histochemical (IHC) markers like p53, p63, PDPN, C-erb-B2, CK19, and VEGF in oral squamous cell carcinoma (OSCCs) is of interest to dentists. Sixty formalin-fixed paraffin embedded tissue blocks from the Department of Oral Pathology, New Horizon Dental College and Research, Institute, Sakri, Bilaspur, Chhattisgarh, India. The conventional IHC method was used to assess the expression of p53, p63, PDPN, C- erb-B2, CK19 and VEGF using the different antibodies. Data shows that P53, p63 had high values of labeling index (LI) of staining while PDPN, C-erb-B2 had low values of LI of staining. The values of LI of staining for CK19, and VEGF were in between the two types of IHCs. Combining the analysis of multiple IHC markers for OSCC can yield precise cancer diagnosis results.

Role of Ceramide Synthase 1 in Oral Leukoplakia and Oral Squamous Cell Carcinoma: A Potential Linchpin for Tumorigenesis

Background Ceramide (CER), known as a "tumor suppressor lipid," plays a crucial role in promoting apoptosis in cancer cells. Ceramide synthase 1 (CERS1), an enzyme responsible for CER synthesis, holds immense importance. Notably, studies have highlighted that reduced levels of CERS1 confer protection to oral squamous cell carcinoma (OSCC) cells against chemotherapeutic agents like cisplatin. However, there is a scarcity of literature exploring the precise role of CERS1 in OSCC. Further investigation is warranted to unravel the intricate relationship of CERS1 in malignant transformation. Aim To compare the salivary CERS1 levels in OSCC, oral leukoplakia (OLK), and healthy individuals. Materials and methods Salivary samples from 15 healthy individuals, OLK patients, and OSCC patients each were obtained and an enzyme-linked immunosorbent assay (ELISA) (MyBioSource, Inc., San Diego, CA) was performed to evaluate salivary CERS1 enzyme levels. Descriptive statistics and Kruskal-Wallis analysis were done using SPSS v23.0 software (IBM Corp., Armonk, NY). Results There was a significant decrease in salivary CERS1 enzyme levels in OSCC (2.08 +/- 0.36 ng/dl) compared to healthy individuals (6.42 +/- 0.42 ng/dl) and OLK patients (4.73 +/- 0.93 ng/dl) (p = 0.05). Conclusion In this study, it was found that CERS1 shows a steady decrease in OLK and OSCC. Further cohort studies with larger sample sizes are needed to provide a basis for the role of CERS1 in OLK and its malignant transformation to OSCC.

A Comparison of Podoplanin Expression in Oral Leukoplakia and Oral Squamous Cell Carcinoma: An Immunohistochemical Study

INTRODUCTION

Oral squamous cell carcinoma (OSCC) accounts for about 90% to 95% of all malignancies of the oral cavity.The majority of OSCCs are preceded by oral potentially malignant disorders (OPMDs). Podoplanin (PDPN) is a mucin-like small transmembrane glycoprotein. Alterations in PDPN immunoexpression have been reported in OPMDs and OSCCs.

OBJECTIVE

The objectives of this study were to evaluate the role of PDPN immunoexpression in oral leukoplakia (OL) and different histological grades of OSCC and to assess the role of PDPN as a potential biomarker for predicting the risk of malignant transformation.

MATERIALS AND METHODOLOGY

Immunohistochemical analysis for PDPN was performed in 45 histologically confirmed cases of formalin-fixed, paraffin-embedded specimens of different grades of OSCCs and 15 cases of OLs with 15 cases of the normal oral mucosa (NOM) as controls. The expression and distribution of this marker were analyzed in these lesions.

RESULTS

The immunoexpression of PDPN showed a significant increase in the expression of the percentage of positive cells, staining intensity, location of staining in the epithelium, tumor islands, and within the cells, as well as the mean lymphatic micro vessel density between NOMs, OLs, and different grades of OSCCs.

CONCLUSION

Upregulation of PDPN can be related to the malignant transformation of OLs and biological aggressiveness of OSCCs. The enhanced immunoexpression of PDPN signifies that this immunomarker can have a role in tumor cell differentiation and the neoplastic progression of OSCCs. Increased density of lymphatic vessels suggested an important role of lymphangiogenesis in tumor progression and also as a prognostic factor for lymph nodal metastasis.

Understanding the squamous cell carcinoma immune microenvironment

Primary cutaneous squamous cell carcinoma (cSCC) is the second most common human cancer with a rising incidence of about 1.8 million in the United States annually. Primary cSCC is usually curable by surgery; however, in some cases, cSCC eventuates in nodal metastasis and death from disease specific death. cSCC results in up to 15,000 deaths each year in the United States. Until recently, non-surgical options for treatment of locally advanced or metastatic cSCC were largely ineffective. With the advent of checkpoint inhibitor immunotherapy, including cemiplimab and pembrolizumab, response rates climbed to 50%, representing a vast improvement over chemotherapeutic agents used previously. Herein, we discuss the phenotype and function of SCC associated Langerhans cells, dendritic cells, macrophages, myeloid derived suppressor cells and T cells as well as SCC-associated lymphatics and blood vessels. Possible role(s) of SCC-associated cytokines in progression and invasion are reviewed. We also discuss the SCC immune microenvironment in the context of currently available and pipeline therapeutics.

A meta-analysis reveals the protein profile associated with malignant transformation of oral leukoplakia

The search for biomarkers associated with oral leukoplakia malignant transformation is critical for early diagnosis and improved prognosis of oral cancer patients. This systematic review and meta-analysis aimed to assess protein-based markers potentially associated with malignant transformation of oral leukoplakia. Five database and the grey literature were searched. In total, 142 studies were included for qualitative synthesis, where 173 proteins were investigated due to their potential role in malignant progression from oral leukoplakia (OL) to oral squamous cell carcinoma (OSCC). The abundance of these proteins was analyzed in fixed tissues and/or biofluid samples, mainly by immunohistochemistry and ELISA, and 12 were shared by both samples. Enrichment analysis revealed that the differential abundant proteins are mostly involved with regulation of cell death, regulation of cell proliferation, and regulation of apoptotic process. Also, these proteins are mainly expressed in the extracellular region (55.5%), cell surface (24.8%), and vesicles (49.1%). The meta-analysis revealed that the proteins related to tumor progression, PD-L1, Mdm2, and Mucin-4 were significantly associated with greater abundance in OSCC patients, with an Odds Ratio (OR) of 0.12 (95% CI: 0.04-0.40), 0.44 (95% CI: 0.24-0.81), and 0.18 (95% CI: 0.04-0.86), respectively, with a moderate certainty of evidence. The results indicate a set of proteins that have been investigated across OSCC initiation and progression, and whose transcriptional expression is associated with clinical characteristics relevant to the prognosis and aggressiveness. Further verification and validation of this biomarkers set are strongly recommended for future clinical application.

Lymphatic Vascular Density, the Expression of Podoplanin and Tumor Budding in Oral Squamous Cell Carcinoma

BACKGROUND

Notwithstanding recent advances in oral squamous cell carcinoma (OSCC) management, its mortality rate is still high. It is imperative to investigate new parameters that are complementary to clinical staging for OSCC to provide better prognostic insight. The presence of isolated neoplastic cells or small clusters of up to four cells at the tumor's invasive front, called tumor budding, is a morphological marker of OSCC with prognostic value. Increased lymphatic vascular density (LVD) and a high expression of podoplanin in neoplastic cells have also been associated with worse prognosis in OSCC. To investigate these markers in OSCC, we evaluated differences in LVD and the expression of podoplanin in neoplastic cells between tumors with high-intensity tumor budding versus low-intensity or no tumor budding. In the samples of high-intensity budding, differences in those parameters between the​​ budding area and the area outside the budding were also evaluated. Furthermore, the study assessed differences in LVD and in the expression of podoplanin in neoplastic cells concerning OSCC clinicopathological characteristics.

METHODS

To those ends, we subjected 150 samples of OSCC to immunohistochemistry to evaluate the intensity of tumor budding (via multi-cytokeratin immunostaining). Moreover, the 150 samples of OSCC and 15 specimens of normal oral mucosa (used as a control) were employed to assess LVD and the expression of podoplanin (in neoplastic cells of OSCC and in the lining epithelium of normal oral mucosa), both via podoplanin immunostaining. Data were processed into descriptive and analytical statistics.

RESULTS

No differences were observed neither in the LVD nor in the expression of podoplanin in neoplastic cells concerning sex, age, tobacco smoking, tumor location and tumor size. The LVD was greater in OSCC and in tumors with high-intensity budding than in normal mucosa but did not differ between normal mucosa and tumors with low-intensity or no tumor budding. The data analyses also revealed that LVD was greater in tumors with high-intensity tumor budding than in tumors with low-intensity or no budding and showed no difference in LVD between the budding area and the area outside the budding. When compared to the lining epithelium of the normal mucosa, the expression of podoplanin was greater in neoplastic cells of OSCC, tumors with high-intensity budding and tumors with low-intensity or no tumor budding. The expression of podoplanin in neoplastic cells was also greater in tumors with high-intensity budding and, within those tumors, greater in the budding area than in the area outside de budding.

CONCLUSION

Those findings support the hypothesis that tumor budding is a biological phenomenon associated with the progression and biological behavior of OSCC.

Expression of p53, p63, podoplanin and Ki-67 in recurring versus non-recurring oral leukoplakia

Oral leukoplakia (OL), a potentially malignant disorder, recurs in 40% of cases after surgical removal. Recurrence is a risk factor for malignant transformation. We aimed to examine the prognostic significance of four biomarkers related to cell proliferation: p53, p63, podoplanin (PDPN) and Ki-67 in predicting recurrence. Formalin-fixed-paraffin-embedded specimens from excised OL (n = 73, 33 recurrent; 40 non-recurrent) were collected in a prospective study. Immunohistochemistry was used to visualise expression of p53, p63, PDPN and Ki-67. Image analysis software was used for quantification of p53-, p63- and Ki-67-expressing cells, while PDPN was analysed visually. The expression of all four proteins were higher in recurrent compared with non-recurrent OL, only expression of p53 was statistically significant. In uni- and multivariable Cox regression analyses of individual markers, expression of p63 was significantly associated with higher recurrence risk (p = 0.047). OL with a combined high expression of both p53 and p63 had a significantly higher risk to recur [Log Rank, p = 0.036; multivariate Cox, HR: 2.48 (1.13–5.44; p = 0.024)]. Combination of p53 and p63 expression may be used as a prognostic biomarker for recurrence of OL.