Podoplanin expression in the development and progression of laryngeal squamous cell carcinomas

Expression of podoplanin in tumor cells and lymphatic vessels in both tumoral and peritumoral areas and correlation with metastatic potential of oral squamous cell carcinoma

Aim:

This study aims to study the expression of podoplanin in tumor cells as well as the lymphatic vessels (LVs) in both tumoral and peritumoral areas and correlate the importance of the lymphatic microvascular density (LMVD) in oral squamous cell carcinoma (OSCC) and its metastatic potential.

Materials and Methods:

D2–40 expression and LV density (LVD) were assessed using antibody D240, in 45 diagnosed cases of all the three grades of OSCC. D2–40 expression was evaluated in both epithelial cells as well as the LVs.

Results:

D2–40 expression in OSCC showed two different patterns - diffuse and focal. LMVD was calculated and difference in peritumoral and intra tumoral LVs was also assessed. A marked increase was seen we progressed from well-differentiated tumor to poorly differentiated ones, but this difference was found to be statistically nonsignificant. D2–40 immunostaining also highlighted the presence of lymphatic invasion present within the tumors which was detected by the presence of tumor emboli within the LVs. Overall, no significant correlation was found between D240 epithelial positivity and LVD.

Conclusion:

The expression of podoplanin in tumor cells and lymphatics when correlated with histopathological status and clinically with the lymph node status can definitely help in the adjuvant therapies used in OSCC.

Role of Twist and Podoplanin in Partial Epithelial-Mesenchymal Transition in Oral Squamous Cell Carcinoma

The aim of this study was to perform a comparative analysis of podoplanin (PDPN) and Twist immunoexpressions in lower lip and oral tongue squamous cell carcinomas (LLSCC and OTSCC, respectively). PDPN and Twist immunoexpressions were semi-quantitatively evaluated by analyzing the invasion front, the compressive areas, the large islands and nests and dissociated cells of the chosen carcinomas. Their statistical associations and correlations with clinical-pathological characteristics were verified by the Mann-Whitney and Spearman's test. Twist expression was low in both carcinomas, with <25% labeling on the invasive front. Significant differences were observed for LLSCC (p=0.032) and OTSCC (p=0.025) regarding PDPN immunoexpression in relation to the worst invasion patterns determined by a histological malignancy gradation system. Statistically significant negative correlations between PDPN membrane expression and general (r=-0.356, p=0.024) and cytoplasmic Twist expressions (r=-0.336; p=0.034) in LLSCC were also observed. Twist and PDPN are suggested to be associated to a more aggressive invasion pattern in both LLSCC and OTSCC cases but not related to the different biological behaviors on these anatomical sites. Also, it was seen that PDPN membrane expression is inversely related to general and cytoplasmic Twist expression in LLSCC cases.

Immunohistochemical analysis of cancer-associated fibroblasts and podoplanin in head and neck cancer

Background

To immunohistochemically evaluate the association between the presence of cancer-associated fibroblasts (CAFs) and the tumour expression of podoplanin (PDPN) in head and neck squamous cell carcinoma (HNSCC) and their association with clinicopathological variables.

Material and Methods

A tissue microarray (TMA) with biopsy sections from patients diagnosed with HNSCC was stained with antibodies against the CAFs marker, α-smooth muscle actin (α-SMA), and PDPN. We subsequently evaluated their expression to determine the association between them and with clinicopathological variables including age, primary tumour site, TNM stage, and tumour differentiation grade.

Results

Positive reaction to α-SMA was observed in the tumour stroma, revealing spindle-shaped cells compatible with CAFs, which showed a high expression in 62% of cases and a significant association with laryngeal carcinomas, advanced clinical stages, and lower tumour differentiation (P ≤ 0.05). PDPN staining on tumour cells showed low expression in 72% of cases, and it was not associated with any clinicopathological variable or with the presence of CAFs.

Conclusions

The presence of CAFs in the tumour stroma is related to an aggressive phenotype and could increase as the disease progresses, although based on our findings, it would have no relationship, at least directly, with the expression of PDPN.

Key words:Cancer-associated fibroblasts, myofibroblasts, head and neck neoplasms, podoplanin, immunohistochemistry.

The Emerging Role of NANOG as an Early Cancer Risk Biomarker in Patients with Oral Potentially Malignant Disorders

NANOG, a key regulator of pluripotency and self-renewal in embryonic and adult stem cells, is frequently overexpressed in multiple cancers, including oral squamous cell carcinoma (OSCC). It has been frequently associated with poor outcomes in epithelial cancers, and recently implicated in laryngeal tumorigenesis. On this basis, we investigated the role of NANOG protein expression as an early cancer risk biomarker in oral potentially malignant disorders (OPMD), and the impact on prognosis and disease outcomes in OSCC patients. NANOG expression was evaluated by immunohistochemistry in 55 patients with oral epithelial dysplasia, and 125 OSCC patients. Correlations with clinical and follow-up data were assessed. Nuclear NANOG expression was detected in 2 (3.6%) and cytoplasmic NANOG expression in 9 (16.4%) oral dysplasias. NANOG expression increased with the grade of dysplasia. Cytoplasmic NANOG expression and the histopathological grading were significantly correlated with oral cancer risk, although dysplasia grading was the only significant independent predictor of oral cancer development in multivariate analyses. Cytoplasmic NANOG expression was also detected in 39 (31%) OSCC samples. Positive NANOG expression was significantly associated with tobacco and alcohol consumption, and was more frequent in pN0 tumors, early I-II stages. These data unveil the clinical relevance of NANOG in early stages of OSCC tumorigenesis rather than in advanced neoplastic disease. NANOG expression emerges as an early predictor of oral cancer risk in patients with OPMD.

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

Background

Oral leukoplakia (OL) is a potentially malignant disorder with increased risk for the development of oral squamous cell carcinoma (OSCC). Many cases of OSCC arise from the malignant transformation of preexisting OL. However, the risk of progression into OSCC and the possible prediction of malignant potential of OL remain inconclusive. Recent studies have shown that podoplanin, a mucin-like transmembrane glycoprotein specifically expressed in lymphatic endothelial cells, is expressed in various neoplasms including OSCC, indicating its possible biologic role in tumor cells. In this study, an evaluation of podoplanin expression in OL and OSCC has been carried out to assess its potential role as a biomarker to predict the possibility of malignant transformation in OL cases.

Aims and Objectives

To assess the usefulness of podoplanin as a potential biomarker for predicting the risk of malignant transformation in OL, by comparing its immunohistochemical expression in OL and OSCC.

Materials and Methods

Archival paraffin-embedded blocks of 25 OL cases with varying grades of dysplasia and 30 OSCC cases showing its varying grades were selected. Sections were subjected to immunohistochemical staining for podoplanin and compared with the control group for evaluation of results in the three groups.

Results

A statistically significant increase in podoplanin expression was observed from normal mucosa through OL to OSCC. In the OL cases, the podoplanin staining score progressively increased from mild dysplasia to carcinoma in situ, whereas in OSCC, well-differentiated group showed the maximum expression of podoplanin.

Conclusion

The progressive increase in podoplanin expression through the increasing grades of dysplasia in OL is suggestive of an increased risk for malignant transformation with increased expression of podoplanin in OL cases. A high podoplanin expression in the well-differentiated OSCC may indicate a vital role for podoplanin in the early stages of tumorigenesis.

The Novel Role of SOX2 as an Early Predictor of Cancer Risk in Patients with Laryngeal Precancerous Lesions

The SOX2 gene located at 3q26 is frequently amplified and overexpressed in multiple cancers, including head and neck squamous cell carcinomas (HNSCC). The tumor-promoting activity and involvement of SOX2 in tumor progression has been extensively demonstrated, thereby emerging as a promising therapeutic target. However, the role of SOX2 in early stages of tumorigenesis and its possible contribution to malignant transformation remain unexplored. This study investigates for the first time SOX2 protein expression by immunohistochemistry and gene amplification by real-time PCR using a large series of 94 laryngeal precancerous lesions. Correlations with the histopathological classification and the risk of progression to invasive carcinoma were established. Nuclear SOX2 expression was frequently detected in 38 (40%) laryngeal dysplasias, whereas stromal cells and normal adjacent epithelia showed negative expression. SOX2 gene amplification was detected in 18 (33%) of 55 laryngeal dysplasias. Univariate Cox analysis showed that SOX2 gene amplification (p = 0.046) and protein expression (p < 0.001) but not histological grading (p = 0.432) were significantly associated with laryngeal cancer risk. In multivariate stepwise analysis including age, tobacco, histology, SOX2 gene amplification and SOX2 expression, SOX2 expression (HR = 3.531, 95% CI 1.144 to 10.904; p = 0.028) was the only significant independent predictor of laryngeal cancer development. These findings underscore the relevant role of SOX2 in early tumorigenesis and a novel clinical application of SOX2 expression as independent predictor of laryngeal cancer risk in patients with precancerous lesions beyond current WHO histological grading. Therefore, targeting SOX2 could lead to effective strategies for both cancer prevention and treatment.

Association of the co-expression of SOX2 and Podoplanin in the progression of oral squamous cell carcinomas - an immunohistochemical study

SOX2 is a transcription factor related to the maintenance of stem cells in a pluripotent state. Podoplanin is a type of transmembrane sialoglycoprotein, which plays an important role in tumor progression and metastasis. This study aims to determine association of SOX2 and podoplanin expression in the progression of oral squamous cell carcinomas and to elucidate the association between two proteins.

Expression of 15-lipoxygenase-1 in Merkel cell carcinoma is linked to advanced disease

BACKGROUND

The purpose of this study was to determine whether the expression of 15-lipoxygenase-1 (ALOX15) in primary tumour specimens predicts lymph node metastasis and subsequently clinical outcome in Merkel cell carcinoma (MCC) patients.

METHODS

A retrospective medical chart review of 33 patients was performed between 1994 and 2014. Eleven out of 33 (33%) Patients with primary MCC stages I and II were categorised as group I. Twenty two out of 33 (67%) Patients with regional lymph node metastases and/or distant metastases were defined as group II. All available tumour samples were immunostained for ALOX15, Podoplanin and MCPyV large T-protein antibody.

RESULTS

ALOX15 expression was observed in 19/23 (83%) primary tumour samples and in all lymph node metastasis. Primary tumours in patients with stage III and IV disease showed a higher expression rate of ALOX15 compared to patients with early stage disease (11/12 (92%) and 8/11 (73%), respectively). In group I, five patients (45%) were MCPyV positive, whereas in group II, 15 patients (68%) were MCPyV positive. The median lymphatic vessel density in ALOX15 negative group I primary tumour samples was lower compared to the median lymphatic vessel density in ALOX15 positive group I primary tumour probes (2.7 range, 1-4.3 vs 4.7 range, 4.0-7.3). Furthermore, all 17 samples of MCC metastases showed ALOX15 expression with a median lymphatic vessel density (not lymph node metastases) of 5.3 (range 2.0-7.3).

CONCLUSION

In the current study, we were able to show ALOX15 expression in the primary MCC sample and the metastasis sample. Based on the findings of the current study, expression rate of ALOX15 in primary MCC and metastases is possibly linked to an increased lymphatic vessel density.

Elevated expression of podoplanin and its clinicopathological, prognostic, and therapeutic values in squamous non-small cell lung cancer

Background

Squamous non-small cell lung cancer (SqNSCLC), as a leading cause of cancer-related deaths worldwide, has limited treatment options and poor prognosis. Thus, novel targeted therapies are desperately needed.

Materials and methods

SqNSCLC cases from derivation and validation cohorts were ana-lyzed for podoplanin (PDPN) expression, and its clinicopathological correlation and prognostic prediction. The Human Proteome Map database was used to compare the expression of different lung cancer targets in normal human tissues. Two human lung cancer cell lines, H226 (a SqNSCLC line) and A549 (a non-SqNSCLC line), were examined for PDPN expression. The in vitro cytotoxicity of an anti-PDPN therapy (NZ-1-immunotoxin [NZ-1-IT]) was tested against both lines. The in vivo therapeutic effect of NZ-1-IT was examined in subcutaneous non-small cell lung cancer (NSCLC) xenograft mouse models.

Results

In the derivation cohort, 40% (28/70) were PDPN positive. There was significantly increasing pleural invasion (46.4% vs 9.5%, p=0.001), lymphovascular invasion (25.0% vs 9.5%, p=0.08), and lymph node involvement (53.6% vs 33.3%, p=0.09) in PDPN-positive vs PDPN-negative patients, along with poorer progression-free survival in PDPN-positive patients (p=0.07). The validation cohort with 224 randomly matched cases from The Cancer Genome Atlas data set also displayed significantly shorter overall survival in the group with elevated PDPN mRNA (p=0.05). However, PDPN showed limited expression in normal tissues. PDPN was highly and specifically expressed on the surface of H226 cells instead of A549 cells. Subsequently, PDPN-positive H226 cells were around 800 times more sensitive to anti-PDPN NZ-1-IT therapy than PDPN-negative A549 cells in vitro. Furthermore, NZ-1-IT significantly delayed tumorigenesis only in the H226 subcutaneous mouse model (p<0.05).

Conclusion

Our results demonstrate a distinctively elevated expression of PDPN in SqNSCLC, which is significantly associated with worse clinicopathological features and poorer prognosis. With promising preclinical therapeutic results, anti-PDPN targeted therapy can thus be a robust potential strategy for future SqNSCLC treatment.

C-Type Lectin-Like Receptors As Emerging Orchestrators of Sterile Inflammation Represent Potential Therapeutic Targets

Over the last decade, C-type lectin-like receptors (CTLRs), expressed mostly by myeloid cells, have gained increasing attention for their role in the fine tuning of both innate and adaptive immunity. Not only CTLRs recognize pathogen-derived ligands to protect against infection but also endogenous ligands such as self-carbohydrates, proteins, or lipids to control homeostasis and tissue injury. Interestingly, CTLRs act as antigen-uptake receptors via their carbohydrate-recognition domain for internalization and subsequent presentation to T-cells. Furthermore, CTLRs signal through a complex intracellular network leading to the secretion of a particular set of cytokines that differently polarizes downstream effector T-cell responses according to the ligand and pattern recognition receptor co-engagement. Thus, by orchestrating the balance between inflammatory and resolution pathways, CTLRs are now considered as driving players of sterile inflammation whose dysregulation leads to the development of various pathologies such as autoimmune diseases, allergy, or cancer. For examples, the macrophage-inducible C-type lectin (MINCLE), by sensing glycolipids released during cell-damage, promotes skin allergy and the pathogenesis of experimental autoimmune uveoretinitis. Besides, recent studies described that tumors use physiological process of the CTLRs’ dendritic cell-associated C-type lectin-1 (DECTIN-1) and MINCLE to locally suppress myeloid cell activation and promote immune evasion. Therefore, we aim here to overview the current knowledge of the pivotal role of CTLRs in sterile inflammation with special attention given to the “Dectin-1” and “Dectin-2” families. Moreover, we will discuss the potential of these receptors as promising therapeutic targets to treat a wide range of acute and chronic diseases.

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.

Expression of Podoplanin in Laryngeal Squamous Cell Carcinoma and Dysplasia

INTRODUCTION

In human cancers, podoplanin expression and its correlation with tumour invasive potential raise its possible role as a diagnostic and prognostic marker for cancer.

AIM

To investigate the immunohistochemical expression of podoplanin in laryngeal Squamous Cell Carcinoma (SCC) and dysplasia.

MATERIALS AND METHODS

This study included a total of 60 archived, formalin fixed, paraffin embedded tissue blocks of 40 cases of laryngeal SCC and 20 cases of dysplastic lesions. The samples were immunohistochemically analysed for podoplanin expression.

RESULTS

Podoplanin expression was significantly higher in laryngeal SCC (90%) than laryngeal dysplastic lesions (55%) (p-value=0.002). The expression of podoplanin was significantly increased with the higher grades of dysplasia (p-value=0.016). A significant positive correlation was detected between podoplanin expression in laryngeal SCC and depth of tumour invasion (p-value=0.035), and stage (p-value=0.026).

CONCLUSION

The high expression of podoplanin in laryngeal SCC and its significant correlation with poor prognostic parameters recommends podoplanin as a prognostic marker in laryngeal SCC. In addition, increased podoplanin expression with higher grades of dysplasia, supports its role in malignant transformation and allows us to recommend its evaluation in premalignant lesions.

C-type lectins facilitate tumor metastasis

Metastasis, a life-threatening complication of cancer, leads to the majority of cases of cancer-associated mortality. Unfortunately, the underlying molecular and cellular mechanisms of cancer metastasis remain to be fully elucidated. C-type lectins are a large group of proteins, which share structurally homologous carbohydrate-recognition domains (CRDs) and possess diverse physiological functions, including inflammation and antimicrobial immunity. Accumulating evidence has demonstrated the contribution of C-type lectins in different steps of the metastatic spread of cancer. Notably, a substantial proportion of C-type lectins, including selectins, mannose receptor (MR) and liver and lymph node sinusoidal endothelial cell C-type lectin, are important molecular targets for the formation of metastases in vitro and in vivo. The present review summarizes what has been found regarding C-type lectins in the lymphatic and hematogenous metastasis of cancer. An improved understanding the role of C-type lectins in cancer metastasis provides a comprehensive perspective for further clarifying the molecular mechanisms of cancer metastasis and supports the development of novel C-type lectins-based therapies the for prevention of metastasis in certain types of cancer.

Pathway-related molecules of VEGFC/D-VEGFR3/NRP2 axis in tumor lymphangiogenesis and lymphatic metastasis

Precondition for tumor lymphatic metastasis is that tumor cells induce formation of original and newborn lymphatic vessels and invade surrounding lymphatic vessels in tumor stroma, while some pathway-related molecules play an important role in mechanisms associated with proliferation and migration of lymphatic endothelial cells (LECs) and tumor cells. In lymphangiogenesis and lymphatic metastasis, the pathway-related molecules of VEGFC/D-VEGFR3/NRP2 axis, such as Furin-like enzyme, CNTN1, Prox1, LYVE-1, Podoplanin, SOX18, SDF1 and CXCR4, are direct constitutors as a portion of VEGFC/D-VEGFR3/NRP2 axis, and their biological activities rely on this ligand-receptor system. These axis-related signal molecules could gradually produce waterfall-like cascading effects, mediate differentiation and maturation of LECs, remodel original and neonatal lymphatic vessels, as well as ultimately promote tumor cell chemotaxis, migration, invasion and metastasis to lymphoid tracts. This review summarizes the structure and function features of pathway-related molecules of VEGFC/D-VEGFR3/NRP2 axis, the expression changes of these molecules in different anatomic organs or histopathologic types or development stages of various tumors, the characteristics of transduction, implementation, integration of signal networks, the interactive effects on biological behaviors between tumor cells and lymphatic endothelial cells, and their molecular mechanisms and significances in tumor lymphangiogenesis and lymphatic metastasis.

Immunohistochemical Expression of VEGF and Podoplanin in Uterine Cervical Squamous Intraepithelial Lesions

VEGF and podoplanin (PDPN) have been identified as angiogenesis and/or lymphangiogenesis regulators and might be essential to restrict tumor growth, progression, and metastasis. In the present study, we evaluate the association between the expression of these markers and CIN grade. Immunohistochemistry was performed in 234 uterine cervical samples using conventional histologic sections or TMA with the monoclonal antibodies to VEGF (C-1 clone) and podoplanin (D2-40 clone). Positive-staining rates of VEGF in 191 CIN specimens were significantly associated with histological grade (P < 0.001). Negative and/or focal immunostaining for PDPN were more frequent in CIN 3 (P = 0.016). We found that patients with CIN 3 more frequently had strong and more diffuse staining for VEGF and diminished staining for PDPN (P = 0.018). Strong and more diffuse VEGF immunoexpressions in CIN 2 and CIN 3 were detected when compared to CIN 1. Negative and/or focal PDPN immunoexpression appear to be more frequent in CIN 3. Moderate to strong VEGF expression may be a tendency among patients with high-grade lesions and diminished PDPN expression.

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.

Expression of Podoplanin in Different Grades of Oral Squamous Cell Carcinoma

Background:

The expression of podoplanin is up-regulated in a number of different human cancers, including squamous cell carcinoma of the oral cavity and its relationship with tumor invasion raises the possibility that podoplanin expression could be used as a biomarker for diagnosis and prognosis.

Aim:

The aim of the present study is to evaluate the expression of podoplanin in different grades of squamous cell carcinoma (SCC) and to correlate the expression of podoplanin with relevant clinical features such as age, sex, site and associated habits.

Materials and Methods:

Retrospective study was carried on formalin fixed, paraffin embedded blocks of oral SCC (OSCC) from the archives of Department of Oral and Maxillofacial Pathology, Vishnu Dental College, Bhimavaram. Thirty diagnosed cases were included, of which 10 were well-differentiated SCC (WDSCC) (n = 10), 10 moderately DSCC and 10 poorly DSCC. Demographics including age, sex, gender and associated habit history, were recorded. Immunohistochemical staining was done with podoplanin anti D2–40 antibody, for all the cases of OSCC and assessed qualitatively. The data obtained were tabulated and subjected to statistical analysis.

Results:

In the present study, 27 cases of SCC showed podoplanin expression and remaining three cases showed no expression. The scoring criterion suggested by Yuan et al. was followed for semi-quantitative assessment. OSCC, seven cases presented weak expression (Immunoreactive score [IRS] 0–3), 15 presented moderate expression (IRS Score 4–7) and 5 presented high expression (IRS Score > 8). The assessment of podoplanin expression in the cytoplasm, the membrane and the cytoplasm and membrane (both) of tumor cells showed overall high positivity in the cytoplasmic followed by both and the membrane.

Conclusion:

Podoplanin could be a potent biomarker in assessing the cytoplasm/membrane staining of tumor cells. Furthermore, a high level of podoplanin expression is suggestive of high frequency of lymph node metastasis and immature status in the differentiation process of OSCC.

New insights into the role of podoplanin in epithelial-mesenchymal transition

Podoplanin is a small mucin-like transmembrane protein expressed in several adult tissues and with an important role during embryogenesis. It is needed for the proper development of kidneys and lungs as well as accurate formation of the lymphatic vascular system. In addition, it is involved in the physiology of the immune system. A wide variety of tumors express podoplanin, both in the malignant cells and in the stroma. Although there are exceptions, the presence of podoplanin results in poor prognosis. The main consequence of forced podoplanin expression in established and tumor-derived cell lines is an increase in cell migration and, eventually, the triggering of an epithelial-mesenchymal transition, whereby cells acquire a fibroblastoid phenotype and increased motility. We will examine the current status of the role of podoplanin in the induction of epithelial-mesenchymal transition as well as the different interactions that lead to this program.

Expression of podoplanin in the invasion front of oral squamous cell carcinoma is not prognostic for survival

Podoplanin is involved in actin remodeling of the cytoskeleton of tumor cells and may promote tumor cell invasion by increasing cell motility and formation of filopodia-like membrane protrusions. Podoplanin is expressed in a variety of tumors, but its role in head and neck cancer, particularly in oral squamous cell carcinoma, remains unclear. We studied podoplanin expression by immunohistochemistry in 92 oral squamous cell carcinomas (OSCC) using a monoclonal antibody against an epitope of podoplanin (D2-40). In terms of the number of stained cells, 34 OSCC (38 %) had low podoplanin expression (less than 33 % of cells), 33 (36 %) showed moderate expression (between 34 and 66 % of cells), and 21 (22 %) showed high expression. The intensity of immunostaining was strong in 26 (28 %) cases, moderate in 36 (40 %), and weak or negative in the remaining 30 tumors (32 %). Immunohistochemical expression of podoplanin was associated with a tumor histological grade. A diffuse pattern of podoplanin expression significantly decreased in moderately differentiated (37 %) and poorly differentiated (20 %) carcinomas compared to well-differentiated (43 %) carcinomas. In addition, the focal expression of podoplanin in the invasion front of the tumor, without expression in the tumor center, was observed in 72 % of well-differentiated tumors, 27 % of moderate tumors, and 0 % of poorly differentiated tumors. Moreover, a trend was found toward an association of diffuse podoplanin staining with the development of second primary carcinomas (13 %), in contrast to its expression in the invasion front (3 %). No association was observed between podoplanin expression and nodal metastasis.

Podoplanin promotes the invasion of oral squamous cell carcinoma in coordination with MT1-MMP and Rho GTPases

Podoplanin overexpression has been reported in various cancers, however, the precise mechanism for podoplanin to promote tumor progression remains elusive. In the present study, podoplanin overexpression was found associated with invasiveness both in OSCC tissues and cell lines. Moreover, the cell invasiveness increased with forced podoplanin expression and decreased when podoplanin was knockdown, indicating podoplanin-mediated cell invasion during OSCC progression. To further identify the role of podoplanin in tumor invasion, cell spreading and immunofluorescence assay were performed firstly. It was found that podoplanin knockdown caused an impaired cell spreading with reduced filopodia and the premature assembly of stress fibers while podoplanin overexpression induced an increase in cellular protrusions and stress fibers with extensive parallel bundles. Then, pull-down assays revealed forced podoplanin expression increased Cdc42 activity and reduced RhoA activity while podoplanin knockdown decreased Cdc42 and increased RhoA markedly. Moreover, a hierarchy of crosstalk between RhoA and Cdc42 was confirmed in podoplanin-mediated cell motility. On the other hand, a significant correlation between podoplanin and MT1-MMP expression in OSCCs was found both in vivo and in vitro, co-located in invasive cells and cellular protrusions. Furthermore, our data showed MT1-MMP knockdown significantly blocked the upregulation of cell motility by forced podoplanin expression, indicating that MT1-MMP played a role in podoplanin-mediated tumor invasion. To further confirm the interaction between RhoA/Cdc42 complex, MT1-MMP and podoplanin, co-precipitation experiments were performed. Both the co-precipitation of podoplanin with MT1-MMP and the podoplanin-induced specific binding of MT1-MMP to Cdc42 were found, and immunofluorescence revealed the co-location of podoplanin, MT1-MMP and Cdc42 at the plasma membrane and filopodia induced an increase in cellular protrusion and stress fibers formation. Moreover, MT1-MMP inhibition could partly rescue the increase of Cdc42 activity caused by forced podoplanin expression. Taken together, our data demonstrated a hierarchy of crosstalk between RhoA and Cdc42 was involved in podoplanin-mediated cytoskeleton remodeling and invasion; the co-location and co-ordination of podoplanin, Cdc42 and MT1-MMP in the invadopodia might induce cytoskeleton remodeling, ECM degradation and tumor invasion, while podoplanin-induced EMT may not be indispensible during OSCC progression.

Analysis of gene expression identifies candidate markers and pathways in pre-eclampsia

Pre-eclampsia is a serious multisystem disorder and causes significant increase in both maternal and foetal morbidity and perinatal mortality globally. Due to the limited understanding of the molecular mechanism of pre-eclampsia, the current study conducted bioinformatic analyses to screen key regulators involved in pre-eclampsia. The gene expression profiling dataset GSE44711 containing 8 early-onset pre-eclampsia placentas and 8 gestational-age-matched control placentas was downloaded from the Gene Expression Omnibus database. Differentially expressed genes (DEGs) were screened by limma software package, which were then subjected to Gene Ontology and Kyoto Encyclopedia of Genes and Genomes pathway analysis on the Database for Annotation, Visualization, and Integrated Discovery website. Finally, protein-protein interaction network was constructed using the Search Tool for the Retrieval of Interacting Genes database. In total, 192 DEGs including 106 upregulated and 86 downregulated genes were obtained. Proteoglycan 2 and podoplanin were the most significantly up- and downregulated genes, respectively. In addition, three potential pathways and their related DEGs: spermidine/spermine N1-acetyltransferase 1, amiloride-binding protein 1 and adenosylmethionine decarboxylase 1 were associated with arginine and proline metabolism. Vascular endothelial growth factor C; phosphatidylinositol-4, 5-bisphosphate 3-kinase, catalytic subunit beta; collagen, type I, alpha 1 (COL1A1); and fibronectin 1 (FN1) were associated with focal adhesion. COL6A1 as well as COL1A1 and FN1 were involved in extra-cellular matrix-receptor interaction. The current study identified several potential genes and three pathways which may be considered as candidate targets for diagnosis and therapy of pre-eclampsia.

Immunohistochemical expression of Type IV Collagen and Autocrine Motility Factor Receptor in Odontogenic Tumours

BACKGROUND

Autocrine motility factor receptor (AMFR) is a tumour motility stimulating protein secreted by tumour cells. The protein encoded by this gene is a glycosylated transmembrane protein and a receptor for autocrine motility factor. It has been known to play a role in progression of neoplastic lesions. Basement membranes are specialized extracellular matrices that serve as structural barriers as well as substrates for cellular interactions. The network of type IV collagen is thought to define the scaffold integrating other components such as laminins and perlecan into highly organized supramolecular architecture. The aim of this study was to determine and evaluate the immunohistochemical expression of Type IV Collagen and Autocrine motility factor receptor in odontogenic lesions.

MATERIALS AND METHODS

Immunohistochemical expression of Type IV Collagen and Autocrine motility factor receptor was evaluated in 31 odontogenic lesions, including unicystic ameloblastoma, multicystic ameloblastoma, keratocystic odontogenic tumour and ameloblastic carcinoma. Normal follicular tissue formed the control.

RESULTS

Maximum expression for Type IV Collagen was seen in multicystic ameloblastoma and minimum expression in keratocystic odontogenic tumour. The maximum expression of AMFR was seen in ameloblastic carcinoma and minimum expression in multicystic ameloblastoma.

CONCLUSION

The results of this study suggested an association of loss of expression of type IV Collagen with progression of lesion. AMFR expression was found to be associated with the aggressive potential of tumours.

Podoplanin expressing cancer-associated fibroblasts in oral cancer

Podoplanin is a mucin-type glycoprotein widely used as a lymphatic endothelial marker. It is well known that podoplanin is expressed in various neoplasms including oral squamous cell carcinoma (OSCC). Apart from podoplanin expression in cancer cells, recent studies have suggested that podoplanin expression in stromal cancer-associated fibroblasts (CAFs) may be an indicator of poor prognosis in various cancers. In the present study, we performed immunohistochemical analyses of podoplanin and alpha-smooth muscle actin (α-SMA) in OSCC in order to clarify the significance of podoplanin-positive CAFs. Paraffin-embedded tissue specimens of 69 primary and 29 corresponding metastatic lesions in lymph nodes were examined immunohistochemically using antibodies against podoplanin and α-SMA. Podoplanin-positive stromal fibroblasts were detected in 51 (73.9%) of the 69 primary OSCCs and 24 (82.8%) of the 29 lymph nodes metastases. α-SMA immunoreactivity was observed in 39 (56.5%) of the primaries and 24 (82.8%) of the metastases. Further examination showed that 38 (74.5%) of the primary lesions and 23 (95.8%) of the metastases with podoplanin positivity were also positive for α-SMA. In addition, the intensity of α-SMA immunoreactivity increased as that of podoplanin became stronger. Podoplanin-positive CAFs are considered to be myofibroblasts that may contribute to progression of oral cancer.

The role of podoplanin in the biology of differentiated thyroid cancers

Podoplanin (PDPN), a mucin-type transmembrane glycoprotein specific to the lymphatic system is expressed in a variety of human cancers, and is regarded as a factor promoting tumor progression. The purpose of this study was to elucidate the molecular role of PDPN in the biology of thyroid cancer cells. PDPN expression was evaluated in primary thyroid carcinomas and thyroid carcinoma cell lines by RT-qPCR, Western blotting, IF and IHC. To examine the role of podoplanin in determining a cell's malignant potential (cellular migration, invasion, proliferation, adhesion, motility, apoptosis), a thyroid cancer cell line with silenced PDPN expression was used. We observed that PDPN was solely expressed in the cancer cells of 40% of papillary thyroid carcinoma (PTC) tissues. Moreover, PDPN mRNA and protein were highly expressed in PTC-derived TPC1 and BcPAP cell lines but were not detected in follicular thyroid cancer derived cell lines. PDPN knock-down significantly decreased cellular invasion, and modestly reduced cell migration, while proliferation and adhesion were not affected. Our results demonstrate that PDPN mediates the invasive properties of cells derived from papillary thyroid carcinomas, suggesting that podoplanin might promote PTC progression.

Investigation of biomarker in laryngeal carcinomas

BACKGROUND

The aim of the study is to determine whether there is a role of podoplanin and glutathione S-transferases T1 (GST-T1) expression in laryngeal squamous cell carcinoma.

METHODS

In this study, 33 patients were enrolled and gene expression analysis was performed by qRT-PCR. The podoplanin and GST-T1 expression patterns were analyzed to determine their correlation with clinicopathologic parameters of laryngeal cancer.

RESULTS

Of all included patients, 20 had supraglottic, and 13 had glottic laryngeal cancer. Increased expression of podoplanin was found in seven (35%) supraglottic tumor tissues and seven (53.8%) glottic tumor tissues, but GST-T1 expression was not detected.

CONCLUSION

Podoplanin expression did not show any prediction for tumor differentiation, regional metastasis, thyroid cartilage invasion, lymphatic vessel invasion, or tumor differentiation for laryngeal cancer, and also there were no significant differences in podoplanin expression between glottic and supraglottic regions, but extracapsullar extension is almost statistically significance (P = 0.05).

Prognostic value of podoplanin expression in oral squamous cell carcinoma--a regression model auxiliary to UICC classification

Podoplanin, a type I transmembrane glycoprotein with an effect of platelet aggregation, has been reported to be one of the possible prognostic factors of oral squamous cell carcinoma (OSCC). However, the biological significance of podoplanin is largely unclear. The aim of this study was to develop a practical model for the prediction of prognosis using the grade of podoplanin expression, and also to evaluate the biological function of podoplanin. Eighty-two specimens of patients with previously untreated OSCC, who underwent either biopsy or surgery, were histopathologically and immunohistochemically analyzed. These 82 cases were composed of 66 well-differentiated, 10 moderately differentiated and 6 poorly differentiated OSCC. Podoplanin was successfully immunostained in 78 specimens, and was detected in most cases, but the frequency of positive cells varied. The prognosis of patients with more than 50 % podoplanin-positive tumor cells was significantly poorer than that of the other patients. Multivariate hazards regression analysis suggested that a linear combination of covariates, OSCC patients with more or less than 50 % podoplanin expression, age of more or less than 70 years old, mode of invasion and T3, T4 or T2 versus T1 of the UICC T-stage classification was the most effective model for evaluating the prognosis of OSCC patients. Additionally, podoplanin expression had a significant relationship to UICC clinical stage and the expression of Ki-67. An effective regression model using podoplanin expression was developed for evaluating the prognosis of OSCC and the biological significance of podoplanin was suggested to be associated with the growth and/or progression of OSCC.

Diffuse malignant peritoneal mesothelioma: long-term survival with complete cytoreductive surgery followed by hyperthermic intraperitoneal chemotherapy (HIPEC)

BACKGROUND

Prognosis of diffuse malignant peritoneal mesothelioma (DMPM) has been recently improved by cytoreductive surgery and hyperthermic intraperitoneal chemotherapy (HIPEC). As with other peritoneal surface malignancies, the survival benefit is maximal when a complete surgical cytoreduction is achieved, but additional factors predicting long-term outcome are still poorly understood. We sought to investigate outcome and prognostic factors in patients with DMPM treated by complete cytoreduction and HIPEC.

METHODS

From a prospective database, we selected 108 patients with DMPM undergoing complete cytoreduction (residual tumour nodules ≤2.5 mm) and closed-abdomen HIPEC with cisplatin and doxorubicin or mitomycin-C. Twenty-seven patient-, tumour- and treatment-related variables were assessed by multivariate analysis with respect to overall (OS) and progression-free (PFS) survival. A panel of immunohistochemical markers was tested.

RESULTS

Operative mortality was 1.9% and major morbidity 38.9%. Median follow-up was 48.8 months (95% confidence interval (CI) 37.1-60.6). Median OS and PFS were 63.2 months (95%CI 29.6-96.7) and 25.1 months (95%CI 5.1-45.1). The survival curve reached a plateau after 7 years, representing 19 actual survivors of 39 patients (43.6%) with potential follow-up ≥7 years. Cytokeratin 5/6, calretinin, Wilms tumour-1 (WT-1), podoplanin and epithelial growth factor receptor (EGFR) were mostly positive. At multivariate analysis, epithelial histological subtype, negative lymph-nodes, ≤10% Ki67-positive cells correlated with both increased OS and PFS. Positive podoplanin correlated to increased PFS.

CONCLUSIONS

After complete cytoreduction and HIPEC, prognosis of DMPM is primarily dependent on pathologic and biologic features. Patients with DMPM surviving ≥7 years appeared to be cured. Cure rate was 43.6%. Proliferative index and podoplanin may be used for prognostic stratification.

Podoplanin expression in oral leukoplakia: tumorigenic role

OBJECTIVES

Recent studies have identified podoplanin, a mucin-type transmembrane glycoprotein, as a biomarker for oral cancer risk in patients with oral leukoplakia (OPL). The aim of this study was to investigate the potential association between podoplanin and the risk of malignant transformation of OPL with epithelial dysplasia.

MATERIALS AND METHODS

In this retrospective study, podoplanin immunoexpression was analyzed in 58 patients with oral leukoplakia that showed epithelial dysplasia. Lesions with podoplanin expression in the basal and suprabasal layers of oral epithelium at one area or showing suprabasal expression at two or more areas were considered as positive. Association between podoplanin expression and oral cancer development was analyzed.

RESULTS

Twenty-two of the 58 lesions (38%) were classified as podoplanin-positive, and the remaining 36 (62%) lesions were considered podoplanin-negative. The expression of podoplanin was correlated with the grade of dysplasia (p<0.0005), and with the risk of progression to oral cancer (p<0.0005). In multivariate survival analysis, only premalignant oral lesions displaying positive podoplanin expression showed a significantly increased risk of developing an oral squamous cell carcinoma (hazard ratio=8.738, p=0.007).

CONCLUSION

Podoplanin could be a valuable biomarker for risk assessment of malignant transformation in patients with OPL along with histological assessment.

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.

Podoplanin is a novel myoepithelial cell marker in pleomorphic adenoma and other salivary gland tumors with myoepithelial differentiation

The expression of podoplanin, one of the representative immunohistochemical markers for lymphatic endothelium, is upregulated in various kinds of cancers. Based on our previous studies, we have developed a hypothesis that podoplanin plays a role in cell adhesion via its association with extracellular matrix (ECM). Since salivary pleomorphic adenoma is histologically characterized by its ECM-enriched stroma, we firstly wanted to explore the expression modes of podoplanin in pleomorphic adenoma and related salivary tumors by immunohistochemistry. In normal salivary gland, podoplanin was specifically localized in myoepithelial cells, which were also positively labeled by antibodies against P63, of the intercalated duct as well as acini. In pleomorphic adenoma, podoplanin was colocalized with P63 and CD44 in basal cells of glandular structures as well as in stellate/spindle cells in myxochondroid matrices, where perlecan and hyaluronic acid were enriched. The expression of podoplanin was confirmed at both protein and mRNA levels in pleomorphic adenoma cell systems (SM-AP1 and SM-AP4) by using immunofluorescence, western blotting, and reverse transcription polymerase chain reaction. Podoplanin was localized on the cell border as well as in the external periphery of the cells. Moreover, podoplanin expression was also confirmed in tumor cells with myoepithelial differentiation in myoepithelioma and intraductal papilloma. The results indicate that podoplanin can be regarded as a novel myoepithelial marker in salivary gland tumors and suggest that podoplanin's communication with ECM molecules is essential to phenotypic differentiation to myoepithelial cells.

Platelet CLEC-2 and podoplanin in cancer metastasis

It has long been recognised that the function of platelets in health and disease span far beyond their roles in haemostasis and thrombosis. The observation that tumour cells induce platelet aggregation was followed by extensive experimental evidence linking platelets to cancer progression. Aggregated platelets coat tumour cells during their transit through the bloodstream and mediate adherence to vascular endothelium, protection from shear stresses, evasion from immune molecules, and release of an array of bioactive molecules that facilitate tumour cell extravasation and growth at metastatic sites. The sialyated membrane glycoprotein podoplanin is found on the leading edge of tumour cells and is thought to influence their migratory and invasive properties. Podoplanin elicits powerful platelet aggregation and is the endogenous ligand for the platelet C-type lectin receptor, CLEC-2, which itself regulates podoplanin signalling. Here, the bidirectional relationship between CLEC-2 and podoplanin is described and considered in the context of tumour growth and metastasis.

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

Oral erythroplakia (OE) is a notoriously aggressive oral premalignant lesion with a high tendency to oral cancer development, but it's biological behavior is largely unknown. The objective of the current study was to determine podoplanin and ABCG2 immunoexpression in OE and both correlation to malignant transformation of OE. In a retrospective follow-up study, the expression patterns of podoplanin and ABCG2 were determined using immunohistochemistry in samples from 34 patients with OE, including patients with untransformed lesions (n=17) and patients with malignant transformed lesions (n=17). Podoplanin and ABCG2 expression was observed in 15 (44.1%) and 21 (61.8%) of 34 patients, respectively. Multivariate analysis revealed that podoplanin and ABCG2 expression was associated with 6.31-fold (95% confidence interval [CI], 1.02-38.92; P=0.047) and 14.39-fold (95% CI, 2.02-102.29; P=0.008) increased the risk of transformation, respectively. Point prevalence analysis revealed that 90.9% (95% CI, 70.7-100) of the patient with both podoplanin and ABCG2 positivity developed oral cancer. Collectively, our data indicated that the expression patterns of podoplanin and ABCG2 in OE were associated with oral cancer development, suggesting that podoplanin and ABCG2 may be valuable predictors for evaluating oral cancer risk.

Podoplanin expression by cancer-associated fibroblasts predicts poor outcome in invasive ductal breast carcinoma

AIMS

It has recently been shown that podoplanin, a mucin-type glycoprotein, is expressed by cancer cells and cancer-associated fibroblasts (CAFs), and promotes cancer cell migration and invasiveness. The biological role of podoplanin expression in tumour stroma of invasive ductal carcinoma of the breast (IDC) has not been determined.

METHODS AND RESULTS

Podoplanin expression was analysed in 117 cases of IDC and 27 cases of fibrocystic change, as well as in breast cancer cell lines, with the use of immunohistochemistry and real-time polymerase chain reaction. In 82.1% of analysed tumours, podoplanin was found only in CAFs. Only two of 117 IDC cases (1.7%) were characterized by expression of this glycoprotein in cancer cells. None of the fibrocystic changes or stroma surrounding normal ducts showed podoplanin expression. Podoplanin-positive CAFs correlated with tumour size (P = 0.0125), grade of malignancy (P = 0.0058), lymph node metastasis (P = 0.0149), lymphovascular invasion (LVI) (P = 0.0486) and Ki67 expression in cancer cells (P = 0.0128). High-level podoplanin expression (>50% of positive stroma) in the tumour stroma was significantly associated with a negative oestrogen status (P = 0.0201). Univariate, but not multivariate, analysis showed that podoplanin expression by CAFs was associated with poor patient outcome (P = 0.0202).

CONCLUSIONS

Our results suggest that podoplanin expression by CAFs could be an unfavourable prognostic marker for IDC.

Relationship of Podoplanin and Glutathione S-transferases T1 Expression with Laryngeal Cancer

The aim of this study is to determine whether there is a role of podoplanin and glutathione S-transferases T1 (GST-T1) expression in laryngeal squamous cell carcinoma. The study was completed with 33 patients and gene expression analysis was performed by qRT-PCR. The podoplanin and GST-T1 expression patterns were analyzed to determine their correlation with clinicopathologic parameters of laryngeal cancer. Of all patients, 20 had supraglottic, and the remaining 13 had glottic laryngeal cancer. Increased expression of podoplanin was found in 14 tumor tissues, but GST-T1 expression was not detected. Podoplanin expression did not show any prediction for regional metastasis, thyroid cartilage invasion, lymphatic vessel invasion or tumor differentiation for laryngeal cancer, also there were no significant differences in podoplanin expression between glottic and supraglottic regions, but extracapsullar extension is almost statistically significant (p=0,05).

Role of podoplanin expression in esophageal squamous cell carcinoma: a retrospective study

Lymphatic metastasis is the predominant cause of the low overall survival of patients with esophageal squamous cell carcinoma (ESCC), as there are no faithful methods available predicting early metastasis. Recent studies suggest an effect of podoplanin expression on metastatic spreading to lymph nodes. The purpose of this study was to investigate the influence of podoplanin expression on lymphatic metastasis and tumor cells, and to find the relationship between podoplanin expression and prognosis of patients with ESCC. We evaluated the level of podoplanin expression on tumor cells and the lymphatic vessel density change of tumor mass compared with normal tissue from the same patient through D2-40 immunohistochemistry staining, and analyzed associations between these two variables and various clinicopathologic parameters individually or conjunctively. There was an association between podoplanin expression and the frequency of lymph node metastases. In 45 patients (80%), podoplanin was expressed on the tumor cells. Twenty-one patients (37.5%) showed high levels of expression. The 5-year disease-free survival rate (5%) for patients with high levels of podoplanin expression was significantly lower (P < 0.001) than for patients with low and moderate expression of podoplanin (54% and 27%, respectively). We concluded that podoplanin is expressed frequently in ESCC, and that the expression of podoplanin on cancer cells, lymphatics, or both is correlated with lymphatic metastasis and clinical outcome.

Podoplanin expression correlates with sentinel lymph node metastasis in early squamous cell carcinomas of the oral cavity and oropharynx

In patients with early head and neck squamous cell carcinoma (HNSCC), occult lymph node metastasis is difficult to predict by clinical or pathological parameters. However, such parameters are necessary to select patients either for elective neck dissection or the sentinel lymph node (SLN) procedure. The membrane glycoprotein podoplanin is normally expressed in lymphatic endothelial cells. Recently, expression of podoplanin by cancer cells was demonstrated to promote tumor cell motility and tumor lymphangiogenesis in vitro. The value of cancer cell-expressed podoplanin was to be determined as a predictive marker for SLN metastasis in early HNSCC of the oral cavity and oropharynx. One hundred twenty patients with HNSCC of the oral cavity and oropharynx undergoing a SLN biopsy were enrolled in this prospective clinical trial of SLN biopsy. Cancer cell-expressed podoplanin was determined by immunohistochemistry using tissue microarrays. Podoplanin expression was quantified by the intensity reactivity score and categorized into expression and nonexpression. SLN examination revealed occult metastasis in 45 patients (37.5%). Twenty-nine of 120 (24.2%) primary HNSCC showed podoplanin expression. Podoplanin expression correlated significantly with SLN metastasis (p = 0.029) and remained a significant predictor for lymph node status even after controlling for tumor stage (p = 0.028). As a predictive marker for SLN metastasis, however, podoplanin expression reached a sensitivity of a mere 36% and a specificity of 83%. Podoplanin expression is associated with metastasis to lymph nodes in vivo. Podoplanin immunohistochemistry in early HNSCC of the oral cavity and oropharynx may help to select patients for the SLN procedure and to identify patients with increased risk for presence of occult lymph node metastasis in the neck.