Association of cytokeratin 17 expression with differentiation in oral squamous cell carcinoma

Unraveling the Keratin Expression in Oral Leukoplakia: A Scoping Review

Intermediate filaments are one of three polymeric structures that form the cytoskeleton of epithelial cells. In the epithelium, these filaments are made up of a variety of keratin proteins. Intermediate filaments complete a wide range of functions in keratinocytes, including maintaining cell structure, cell growth, cell proliferation, cell migration, and more. Given that these functions are intimately associated with the carcinogenic process, and that hyperkeratinization is a quintessential feature of oral leukoplakias, the utility of keratins in oral leukoplakia is yet to be fully explored. This scoping review aims to outline the current knowledge founded on original studies on human tissues regarding the expression and utility of keratins as diagnostic, prognostic, and predictive biomarkers in oral leukoplakias. After using a search strategy developed for several scientific databases, namely, PubMed, Scopus, Web of Science, and OVID, 42 papers met the inclusion and exclusion criteria. One more article was added when it was identified through manually searching the list of references. The included papers were published between 1989 and 2024. Keratins 1-20 were investigated in the 43 included studies, and their expression was assessed in oral leukoplakia and dysplasia cases. Only five studies investigated the prognostic role of keratins in relation to malignant transformation. No studies evaluated keratins as a diagnostic adjunct or predictive tool. Evidence supports the idea that dysplasia disrupts the terminal differentiation pathway of primary keratins. Gain of keratin 17 expression and loss of keratin 13 were significantly observed in differentiated epithelial dysplasia. Also, the keratin 19 extension into suprabasal cells has been associated with the evolving features of dysplasia. The loss of keratin1/keratin 10 has been significantly associated with high-grade dysplasia. The prognostic value of cytokeratins has shown conflicting results, and further studies are required to ascertain their role in predicting the malignant transformation of oral leukoplakia.

The clinical implication and translational research of OSCC differentiation

BACKGROUND

The clinical value and molecular characteristics of tumor differentiation in oral squamous cell carcinoma (OSCC) remain unclear. There is a lack of a related molecular classification prediction system based on pathological images for precision medicine.

METHODS

Integration of epidemiology, genomics, experiments, and deep learning to clarify the clinical value and molecular characteristics, and develop a novel OSCC molecular classification prediction system.

RESULTS

Large-scale epidemiology data (n = 118,817) demonstrated OSCC differentiation was a significant prognosis indicator (p < 0.001), and well-differentiated OSCC was more chemo-resistant than poorly differentiated OSCC. These results were confirmed in the TCGA database and in vitro. Furthermore, we found chemo-resistant related pathways and cell cycle-related pathways were up-regulated in well- and poorly differentiated OSCC, respectively. Based on the characteristics of OSCC differentiation, a molecular grade of OSCC was obtained and combined with pathological images to establish a novel prediction system through deep learning, named ShuffleNetV2-based Molecular Grade of OSCC (SMGO). Importantly, our independent multi-center cohort of OSCC (n = 340) confirmed the high accuracy of SMGO.

CONCLUSIONS

OSCC differentiation was a significant indicator of prognosis and chemotherapy selection. Importantly, SMGO could be an indispensable reference for OSCC differentiation and assist the decision-making of chemotherapy.

Histological characterization of the human masticatory oral mucosa. A histochemical and immunohistochemical study

BACKGROUND

Histology of human oral mucosa is closely related with its function and anatomical location, and a proper characterization of the human masticatory oral mucosa could be very useful in periodontal pathology.

OBJECTIVE

In the present work, we have carried out a comprehensive study in order to determine the main histological features of parakeratinized (POM) and orthokeratinized (OOM) masticatory human oral mucosa using light and electron microscopy.

METHODS

To perform this, we have used several histological, histochemical and immunohistochemical methods to detect key markets at the epithelial, basement membrane and connective tissue levels.

RESULTS

Our results demonstrated that POM and OOM share many histological similarities, as expected. However, important differences were observed at the epithelial layer of POM, that was significantly thicker than the epithelial layer found in OOM, especially due to a higher number of cells at the stratum spinosum. The expression pattern of CK10 and filaggrin revealed intense signal expression in OOM as compared to POM. Collagen and proteoglycans were more abundant in OOM stroma than in POM. No differences were found for blood vessels and basement membrane.

CONCLUSION

These results may contribute to a better understanding of the pathological conditions affecting the human masticatory oral mucosa. In addition, these findings could be useful for the generation of different types of oral mucosa by tissue engineering techniques.

RESEARCH HIGHLIGHTS

Microscopical features of parakeratinized and orthokeratinized masticatory human oral mucosa showed important differences at both, epithelial and stromal levels. Parakeratinized masticatory human oral mucosa exert thicker epithelial layer, especially, at the stratum spinosum in comparison to orthokeratinized human oral mucosa. Cytokeratin 10 and filaggrin human epithelial markers were intensively expressed in orthokeratinized masticatory human oral mucosa in comparison to parakeratinized masticatory human oral mucosa. At the stromal level, orthokeratinized masticatory human oral mucosa exhibit higher levels of collagen and proteoglycans than parakeratinized masticatory oral mucosa. The deep knowledge of histological features of masticatory oral mucosa could lead to a better understanding of oral mucosa pathology and advanced treatments.

The role of differentiated dysplasia in the prediction of malignant transformation of oral leukoplakia

OBJECTIVE

Oral leukoplakia is the most common oral potentially malignant disorder. Malignant transformation of oral leukoplakia occurs at an annual rate of 1%-7%. WHO-defined classic epithelial dysplasia is an important predictor of malignant transformation of oral leukoplakia, but we have previously shown in a proof of concept study that prediction improves by incorporation of an architectural pattern of dysplasia, also coined as differentiated dysplasia. We aimed to analyze this finding in a larger cohort of patients.

METHOD

For this retrospective study 176 oral leukoplakia patients were included. Biopsies for all patients were assessed for the presence of dysplasia and analyzed for cytokeratin 13 and 17 expression. Moreover, the inter-observer agreement for the diagnosis of differentiated dysplasia was determined.

RESULTS

In total, 33 of 176 patients developed oral squamous cell carcinoma during follow-up. Presence of classic epithelial dysplasia increased cancer risk two-fold (HR = 2.18, p = 0.026). Lesions without classic epithelial dysplasia could be further risk-stratified by the presence of differentiated dysplasia (HR = 7.36, p < 0.001). Combined classic epithelial and differentiated dysplasia imparted a seven-fold increased risk of malignant transformation (7.34, p = 0.001). Inter-observer agreement for the diagnosis of dysplasia, including differentiated dysplasia, was moderate (κ = 0.56, p < 0.001).

DISCUSSION

This study emphasizes the importance of the recognition of the architectural pattern of differentiated dysplasia as a separate entity for risk prediction of malignant transformation of oral leukoplakia. Presence of any pattern of dysplasia results in accurate prediction of malignant transformation risk of oral leukoplakia.

The increased expression of cytokeratin 13 leads to an increase in radiosensitivity of nasopharyngeal carcinoma HNE-3 cells by upregulating ERRFI1

The main factors contributing to the unfavorable outcome in the clinical treatment of patients with nasopharyngeal carcinoma (NPC) patients are radiation resistance and recurrence. This study aimed to investigate the sensitivity and molecular foundation of cytokeratin 13 (CK13) in the radiotherapy of NPC. To achieve this, a human NPC cell line overexpressing CK13, HNE-3-CK13, was constructed. The effects of CK13 overexpression on cell viability and apoptosis under radiotherapy conditions were evaluated using the CCK-8 assay, immunofluorescence, and western blotting (WB). Next-generation sequencing was performed to identify the downstream genes and signaling pathways of CK13 that mediate radiotherapy response. The potential role of the candidate gene ERRFI1 in CK13-induced enhancement of radiosensitivity was investigated through rescue experiments using clone formation and WB. The effects of ERRFI1 on cell viability, cell apoptosis, cell cycle, and the related key genes were further evaluated using CCK-8, immunofluorescence, flow cytometry, quantitative polymerase chain reaction and WB. The results showed that CK13 overexpression in HNE-3 significantly inhibited cell survival under radiotherapy and promoted apoptosis marker γH2AX expression, leading to a significant increase of ERRFI1. Knockdown of ERRFI1 rescued the decreased cell viability and proliferation and the increased cell apoptosis that were caused by CK13 overexpression-mediated radiotherapy sensitization of NPC cells. In this process, EGFR, AKT, and GSK-3β were found involved. In the end, ERRFI1 was proven to inhibit expression levels of CDK1, CDK2, cyclin B1, and cyclin D1, resulting an increased G2/M cell ratio. Overexpression of CK13 enhances the radiosensitivity of NPC cells, which is characterized by decreased cell viability and proliferation and increased apoptosis. This regulation may affect the survival of HNE-3 cells by increasing the expression of ERRFI1 and activating the EGFR/Akt/GSK-3β signaling pathway, providing new potential therapeutic targets for the treatment of NPC.

The comparative evaluation of CK17 expression in histologic and cytological sections of oral squamous-cell carcinoma using immunohistochemistry

BACKGROUD

Squamous-cell carcinoma of the mouth accounts for 90% of all oral cancers and despite advances in treatment methods, its 5-year survival rate is reported to be about 68%. This is due to the late diagnosis of the disease and its resistance to radiotherapy and chemotherapy treatments. One of the methods for diagnosing oral lesions is exfoliative cytology, which is a noninvasive method and can be easily carried out in a dental office.

AIM

The purpose of this study is to find a method that in addition to being fast, accurate and less aggressive has high value and a good degree of accuracy for diagnosis of oral squamous-cell carcinoma.

MATERIALS AND METHODS

In this descriptive-analytical study, 14 patients who were diagnosed with oral squamous-cell carcinoma and 14 specimens from exfoliative cytology of the same tissue before surgery were examined. Immunohistochemically stained specimens were examined by two pathologists simultaneously. Next, five nonoverlapping sections with magnification (×400) and the number of cells stained with the cytokeratin marker 17 are counted and the average percentage of each slide is determined. One-sample t-test is used to analyze the data and significance level in tests is considered 0.05.

RESULTS

In examining the diagnostic value of cytology, we concluded that out of 280 affected cells, 211 cells were stained. Therefore, the sensitivity of cytology in the diagnosis of squamous-cell carcinoma of the mouth is 75.4%. In other words, cytology correctly identifies 75.4% of affected cells as affected. Also, the positive predictive value of cytology was 100%.

Cytokeratin 13 (CK13) expression in cancer: a tissue microarray study on 10,439 tumors

Cytokeratin 13 (CK13) is a type I acidic low molecular weight cytokeratin, which is mainly expressed in urothelium and in the squamous epithelium of various sites of origin. Loss of CK13 has been implicated in the development and progression of squamous epithelial neoplasms. To comprehensively determine CK13 expression in normal and neoplastic tissues, a tissue microarray containing 10,439 samples from 131 different tumor types and subtypes as well as 608 samples of 76 different normal tissue types was analyzed by immunohistochemistry. CK13 immunostaining was detectable in 42 (32.1%) of the 131 tumor categories including 24 (18.3%) tumor types with at least one strongly positive case. The highest rate of positive staining was found in various urothelial neoplasms (52.1-92.3%) including Brenner tumor of the ovary (86.8%) and in squamous cell carcinomas from various sites of origin (39.1-77.6%), Warthin tumors of parotid glands (66.7%), adenosquamous carcinomas of the cervix (33.3%), thymomas (16.0%), and endometroid carcinomas of the ovary (15.3%). Twenty other epithelial or germ cell neoplasms showed - a usually weak - CK13 positivity in less than 15% of the cases. In bladder cancer, reduced CK13 expression was linked to high grade and advanced stage (p < 0.0001 each). In squamous cell carcinoma of the cervix, reduced CK13 immunostaining was related to high grade (p = 0.0295) and shortened recurrence-free (p = 0.0094) and overall survival (p = 0.0274). In a combined analysis of 1,151 squamous cell carcinomas from 11 different sites of origin, reduced CK13 staining was linked to high grade (p = 0.0050). Our data provide a comprehensive overview on CK13 expression in normal and neoplastic human tissues. CK13 expression predominates in urothelial neoplasms and in squamous cell carcinomas of different organs, and a loss of CK13 expression is associated with aggressive disease in these tumors.

Utility of CK8, CK10, CK13, and CK17 in Differential Diagnostics of Benign Lesions, Laryngeal Dysplasia, and Laryngeal Squamous Cell Carcinoma

There are no reliable immunohistochemical markers for diagnosing laryngeal squamous cell carcinoma (SCC) or diagnosing and grading laryngeal dysplasia. We aimed to evaluate the diagnostic utility of CK8, CK10, CK13, and CK17 in benign laryngeal lesions, laryngeal dysplasia, and laryngeal SCC. This retrospective study included 151 patients diagnosed with laryngeal papilloma, laryngeal polyps, laryngeal dysplasia, and laryngeal SCC who underwent surgical treatment between 2010 and 2020. Immunohistochemistry (IHC) was carried out using specific monoclonal antibodies against CK8, CK10, CK13, and CK17. Two experienced pathologists performed semi-quantitative scoring of IHC positivity. The diagnostic significance of the markers was analyzed. CK13 showed a sensitivity of 100% and a specificity of 82.5% for distinguishing between laryngeal SCC and laryngeal dysplasia and benign lesions. CK17 showed a sensitivity of 78.3% and specificity of 57.1% for the detection of laryngeal SCC vs. laryngeal dysplasia. CK10 showed a sensitivity of 80.0% for discriminating between low-grade and high-grade dysplasia, and a specificity of 61.1%. Loss of CK13 expression is a reliable diagnostic tool for diagnosing laryngeal lesions with malignant potential and determining resection lines. In lesions with diminished CK13 expression, CK17 could be used as an auxiliary immunohistochemical marker in diagnosing laryngeal SCC. In CK13-negative and CK17-positive lesions, CK10 positivity could be used to determine low-grade dysplasia. CK8 is not a useful IHC marker in differentiating between benign laryngeal lesions, laryngeal dysplasia, and laryngeal SCC.

Use of Cytokeratin 17 in the Differentiation Between Desmoplastic Trichilemmoma and Cutaneous Basal Cell Carcinoma

ABSTRACT

Desmoplastic trichilemmoma (DTL) is a variant of trichilemmoma characterized by a prominent desmoplastic stroma that may mimic invasive carcinoma. These lesions typically show features of a conventional trichilemmoma at the periphery, surrounding dense hyalinized stroma with entrapped cords of tumor cells. On a small or superficial biopsy, DTL may pose a diagnostic challenge in distinguishing this benign adnexal neoplasm from invasive carcinoma, particularly basal cell carcinoma (BCC). We aimed to investigate whether the immunohistochemical expression of cytokeratin 17 (CK17) would be useful in the differentiation between DTL and BCC. CK17 is expressed in normal adnexal structures and has been shown to demonstrate strong staining in BCCs. Expression of CK17 was examined in 23 cases of DTL and 23 BCCs. An immunoreactivity score was assigned using the percentage of tumor cells staining with scoring as follows: 0, complete negativity; 1, < 15% tumor cells staining; 2, 15%-84% tumor cells staining; and 3, >85% staining. All cases of BCC scored as 3, whereas 18% of DTL scored as 3. The mean percent staining for CK17 was significantly higher for BCCs (97% of tumor cells) than DTLs (57% of tumor cells); P < 0.001 in the unpaired t test. The pattern of CK17 staining may also help differentiate between cases scoring 3. All BCCs showed strong diffuse staining throughout, whereas for those cases of DTL with a score of 3, the peripheral basaloid rim in the tumor lobules did not stain. CK17 is a useful adjunct in distinguishing DTL from BCC in small or superficial biopsy specimens.

Oral Lichen Planus and Oral Squamous Cell Carcinoma share key oncogenic signatures

To investigate similarities in the gene profile of Oral Lichen Planus and Oral Squamous Cell Carcinoma that may justify a carcinogenic potential, we analyzed the gene expression signatures of Oral Lichen Planus and Oral Squamous Cell Carcinoma in early and advanced stages. Based on gene expression data from public databases, we used a bioinformatics approach to compare expression profiles, estimate immune infiltrate composition, identify differentially and co-expressed genes, and propose putative therapeutic targets and associated drugs. Our results revealed gene expression patterns related to processes of keratinization, keratinocyte differentiation, cell proliferation and immune response in common between Oral Lichen Planus and early and advanced Oral Squamous Cell Carcinoma, with the cornified envelope formation and antigen processing cross-presentation pathways in common between Oral Lichen Planus and early Oral Squamous Cell Carcinoma. Together, these results reveal that key tumor suppressors and oncogenes such as PI3, SPRR1B and KRT17, as well as genes associated with different immune processes such as CXCL13, HIF1A and IL1B are dysregulated in OLP.

Diagnostic Utility of Cytokeratin 17 Expression in Oral Squamous Cell Carcinoma: A Review

One of the most common oral malignancies is oral squamous cell carcinoma (OSCC). Although the prevalence of oral cancer varies worldwide, it is generally agreed that the oral cavity is a common anatomical site for cancer, depending primarily on the country (and even particular region in some countries) and gender of the patients. Finding diagnostic markers for OSCC is critical for early diagnosis and personalised treatment of patients.

Because they are overexpressed in OSCC relative to normal mucosa, cytokeratins (CKs), intermediate filaments of the cytoskeletons, are possibilities for diagnostic markers of OSCC. CK17 should be targeted as a diagnostic marker for OSCC among the CKs, as multiple other CKs have been linked to the disease. This study aims to assess the immuno-histochemistry expression of CK17 and to investigate whether there is a link between CK17 and OSCC differentiation.

Cytokeratin 13 promotes radiotherapy sensitivity of nasopharyngeal carcinoma by downregulating the MEK/ERK pathway

BACKGROUND

Radiation therapy is the first treatment choice for nasopharyngeal carcinoma (NPC), while radiation resistance and recurrence have become the primary factors and are associated with poor prognosis in the clinical treatment of NPC patients. The purpose of the present study was to explore the sensitivity and molecular basis of cytokeratin 13 (CK13) that regulates NPC radiotherapy.

METHODS

HNE-3 or C666-1 cell line was used for overexpression and knockdown tests. Under radiotherapy conditions, CCK-8 assay, clone formation assay, and flow cytometry analyzed the effects of CK13 overexpression on cell proliferation, apoptosis, and cell cycle, respectively. In addition, Western blotting detected CK13-mediated downregulation of cell cycle-related genes. The mouse subcutaneous tumor-bearing experiment identified the effects of CK13 overexpression on the treatment of NPC in vivo. Further, Western blotting, CCK-8 assay, and flow cytometry investigated whether the CK13-mediated cell apoptosis involves the MEK/ERK signaling pathway.

RESULTS

Overexpression of CK13 significantly inhibited the survival of HNE-3 cells under radiotherapy in vitro and in vivo, and there was a substantial decrease in cyclin-dependent kinase 4 and 6 (CDK4/6) levels promoting the cell percentage number in the G2/M phase and, subsequently, the ratio of the apoptotic cells. In contrast, the knockdown of CK13 showed the opposite partial regulatory effect. Interestingly, CK13 overexpression also showed a reduction in the survival of C666-1 cells and an increased ratio of the apoptotic cells under radiotherapy treatment. Furthermore, higher levels of CK13 downregulated the MEK/ERK signaling pathway, resulting in decreased HNE-3 cell proliferation and increased apoptosis. However, ERK activators were able to rescue the process partially.

CONCLUSIONS

Together, these results showed that CK13 promoted the radiosensitivity of NPC cells by downregulating the MEK/ERK signaling pathway. Thus, targeting CK13 provided insights into the treatment of NPC radiotherapy.

Genomic and Molecular Signatures of Successful Patient-Derived Xenografts for Oral Cavity Squamous Cell Carcinoma

Background

Oral cavity squamous cell carcinoma (OSCC) is an aggressive malignant tumor with high recurrence and poor prognosis in the advanced stage. Patient-derived xenografts (PDXs) serve as powerful preclinical platforms for drug testing and precision medicine for cancer therapy. We assess which molecular signatures affect tumor engraftment ability and tumor growth rate in OSCC PDXs.

Methods

Treatment-naïve OSCC primary tumors were collected for PDX models establishment. Comprehensive genomic analysis, including whole-exome sequencing and RNA-seq, was performed on case-matched tumors and PDXs. Regulatory genes/pathways were analyzed to clarify which molecular signatures affect tumor engraftment ability and the tumor growth rate in OSCC PDXs.

Results

Perineural invasion was found as an important pathological feature related to engraftment ability. Tumor microenvironment with enriched hypoxia, PI3K-Akt, and epithelial–mesenchymal transition pathways and decreased inflammatory responses had high engraftment ability and tumor growth rates in OSCC PDXs. High matrix metalloproteinase-1 (MMP1) expression was found that have a great graft advantage in xenografts and is associated with pooled disease-free survival in cancer patients.

Conclusion

This study provides a panel with detailed genomic characteristics of OSCC PDXs, enabling preclinical studies on personalized therapy options for oral cancer. MMP1 could serve as a biomarker for predicting successful xenografts in OSCC patients.

On the Cutting Edge of Oral Cancer Prevention: Finding Risk-Predictive Markers in Precancerous Lesions by Longitudinal Studies

Early identification and management of precancerous lesions at high risk of developing cancers is the most effective and economical way to reduce the incidence, mortality, and morbidity of cancers as well as minimizing treatment-related complications, including pain, impaired functions, and disfiguration. Reliable cancer-risk-predictive markers play an important role in enabling evidence-based decision making as well as providing mechanistic insight into the malignant conversion of precancerous lesions. The focus of this article is to review updates on markers that may predict the risk of oral premalignant lesions (OPLs) in developing into oral squamous cell carcinomas (OSCCs), which can logically be discovered only by prospective or retrospective longitudinal studies that analyze pre-progression OPL samples with long-term follow-up outcomes. These risk-predictive markers are different from those that prognosticate the survival outcome of cancers after they have been diagnosed and treated, or those that differentiate between different lesion types and stages. Up-to-date knowledge on cancer-risk-predictive markers discovered by longitudinally followed studies will be reviewed. The goal of this endeavor is to use this information as a starting point to address some key challenges limiting our progress in this area in the hope of achieving effective translation of research discoveries into new clinical interventions.

Utility of Keratins as Biomarkers for Human Oral Precancer and Cancer

Human oral cancer is the single largest group of malignancies in the Indian subcontinent and the sixth largest group of malignancies worldwide. Squamous cell carcinomas (SCC) are the most common epithelial malignancy of the oral cavity, constituting over 90% of oral cancers. About 90% of OSCCs arise from pre-existing, potentially malignant lesions. According to WHO, OSCC has a 5-year survival rate of 45–60%. Late diagnosis, recurrence, and regional or lymph nodal metastases could be the main causes of the high mortality rates. Biomarkers may help categorize and predict premalignant lesions as high risk of developing malignancy, local recurrence, and lymph nodal metastasis. However, at present, there is a dearth of such markers, and this is an area of ongoing research. Keratins (K) or cytokeratins are a group of intermediate filament proteins that show paired and differentiation dependent expression. Our laboratory and others have shown consistent alterations in the expression patterns of keratins in both oral precancerous lesions and tumors. The correlation of these changes with clinicopathological parameters has also been demonstrated. Furthermore, the functional significance of aberrant keratins 8/18 expression in the malignant transformation and progression of oral tumors has also been documented. This article reviews the literature that emphasizes the value of keratins as biomarkers for the prognostication of human oral precancers and cancers.

The Role of Keratin17 in Human Tumours

Keratins are a group of proteins that can constitute intermediate fibers. It is a component of the cytoskeleton and plays an important role in cell protection and structural support. Keratin 17, a Type I keratin, is a multifunctional protein that regulates a variety of biological processes, including cell growth, proliferation, migration, apoptosis and signal transduction. Abnormal expression of KRT17 is associated with a variety of diseases, such as skin diseases. In recent years, studies have shown that KRT17 is abnormally expressed in a variety of malignant tumours, such as lung cancer, cervical cancer, oral squamous cell carcinoma and sarcoma. These abnormal expressions are related to the occurrence, development and prognosis of malignant tumors. In this review, we summarized the expression patterns of KRT17 in a variety of malignant tumours, the role of KRT17 in the development and prognosis of different malignant tumors and its molecular mechanisms. We also discuss the potential clinical application of KRT17 as a valuable therapeutic target.

Diagnostic Value of Cytokeratin 17 during Oral Carcinogenesis: An Immunohistochemical Study

Background

Little is known about the role of cytokeratin 17 (CK17) during oral carcinogenesis. CK17 expression in oral leukoplakia (OL), the most encountered oral potentially malignant disorders and oral squamous cell carcinoma (OSCC), remains very limited. To determine the role of CK17 during oral carcinogenesis and its potential diagnostic marker in oral premalignant and malignant lesions, this study evaluated CK17 expression in OL without dysplasia, OL with dysplasia, and OSCC. CK17 expression in these tissues was compared with those of normal oral mucosa (NOM). Additionally, the relationship between CK17 expression and clinicopathologic factors of OSCC was investigated.

Methods

CK17 expression was evaluated in 186 samples consisting of 12 NOM, 33 OL without dysplasia, 58 OL with dysplasia, and 83 OSCC using immunohistochemistry. The proportion of positively immunostained cells was evaluated and scored.

Results

CK17 was expressed in 8.3%, 54.5%, 74.1%, and 90.4% of NOM, OL without dysplasia, OL with dysplasia, and OSCC, respectively. NOM had a significantly lower CK17 score than OL with dysplasia (p=0.0003) and OSCC (p < 0.0001). A significant association between CK17 expression and histopathologic differentiation of OSCC was found. Tumors with well differentiation had high CK17 expression compared with those of moderate and poor differentiation.

Conclusion

CK17 was overexpressed in OL with dysplasia and OSCC, suggesting that CK17 plays a pivotal role in the development of premalignant lesions and OSCC. Of clinical significance, CK17 may be a good diagnostic marker for oral premalignant lesions and OSCC. Additionally, CK17 could be used as an objective tool to classify histopathologic grade in OSCC. The findings that CK17 expression is high in OSCC but low in NOM imply that CK17 may serve as a potential therapeutic target for OSCC.

Identification of cytokeratin24 as a tumor suppressor for the management of head and neck cancer

To improve management of head and neck squamous cell carcinoma patients, we need to increase our understanding of carcinogenesis, to identify biomarkers, and drug targets. This study aimed to identify novel biomarkers by providing transcriptomics profiles of matched primary tumors, lymph node metastasis, and non-malignant tissue of 20 HNSCC patients as well as by bioinformatic analyses of a TCGA HNSCC cohort, comprising 554 patients. We provide cancer cell signaling networks differentially expressed in tumors versus metastases, such as mesenchymal-epithelial transition, and structural integrity networks. As a proof of principle study, we exploited the data sets and performed functional analyses of a novel cytokeratin, cytokeratin24 (cKRT24), which had not been described as biomarker for tumors before. Survival analysis revealed that low cKRT24 expression correlated with poor overall survival in HNSCC. Experimentally, downregulation of cKRT24 in primary tumors, metastases, and HNSCC cell lines was verified on mRNA and protein level. Cloning and ectopic overexpression of cKRT24 not only affected viability and growth of HNSSC cell lines, but also inhibited tumor growth in murine xenograft studies. We conclude that cKRT24 functions as a tumor suppressor in HNSCC, and may serve as an additional prognostic biomarker and novel target to support current HNSCC treatments.

Identification of oral squamous cell carcinoma markers MUC2 and SPRR1B downstream of TANGO

PURPOSE

Transport and Golgi organization protein 1 (TANGO) promotes angiogenesis and lymphangiogenesis in oral squamous cell carcinoma (OSCC). To elucidate the underlying mechanisms, this study aims to identify and characterize elements downstream of TANGO that mediate its involvement in OSCC.

METHODS

In this study, microarray analysis compared gene expression between control and TANGO-repressed HSC3 cells. Protein expression in 213 OSCC tissue samples was analyzed immunohistochemically.

RESULTS

TANGO repression decreased or increased expression of Mucin 20 (MUC20) and small proline-rich protein 1B (SPRR1B), respectively. MUC20 increased the growth and invasiveness of OSCC cells via altered matrix metalloproteinase (MMP)-2 and E-cadherin expression and c-met phosphorylation. MUC20 induced angiogenesis and lymphangiogenesis by activating vascular endothelial growth factors A and C. In well-differentiated OSCC, SPRR1B expression was high (P = 0.0091) and correlated with keratinization markers and promoted proliferation by inducing mitogen-activated protein kinase p38 phosphorylation. MUC20 expression correlated significantly with clinical stage (P = 0.0024), lymph node metastasis (P = 0.0036), and number of blood and lymph vessels (P < 0.0001). MUC20-expressing cases had a significantly worse prognosis than non-expressing cases (P < 0.0001).

CONCLUSION

MUC20 and SPRR1B located downstream of TANGO may be useful molecular markers for OSCC.

Identification of Novel Candidate Biomarkers for Oral Squamous Cell Carcinoma Based on Whole Gene Expression Profiling

This study aimed to determine the whole gene expression profiles and to ascertain potential biomarkers for 22 oral squamous cell carcinoma (OSCC) among Thai patients using the Illumina Human HT-12, V4.0 Expression BeadChip array. Result indicated 2,724 differential expressed genes composed of 1,560 up-regulated and 1,164 down-regulated genes (unpaired t-test, p-value <0.05; fold change ≥2.0 and ≤2.0). The top 9 up-regulated genes were validated in 39 OSCC cases using TaqMan real-time quantitative reverse transcriptase polymerase chain reaction (qRT-PCR) assay. Among these, the up-regulation of peptidase inhibitor 3 (PI3) and keratin 17 (KRT17) genes was harbored in all 39 OSCC patients (100%). Likewise, statistical analysis indicated that gene expression in 8 selective genes including keratin 16 (KRT16), keratin 14 (KRT14), keratinocyte differentiation-associated protein (KRTDAP), keratin 6B (KRT6B), PI3, S100 calcium binding protein A7 (S100A7), stratifin (SFN) and keratin 5 (KRT5) was significantly associated with well differentiated OSCC (p-value <0.05). Moreover, high level of KRT17 protein was significantly associated with well differentiated OSCC compared to moderately OSCC (p-value = 0.041). Notably, using nested-PCR analysis indicated all OSCC cases in this study were HPV-free. Especially, KRTDAP, PI3, SFN mRNA expression were first reported among patients with OSCC. Conclusion, the whole transcript expression study and TaqMan real-time qRT-PCR assay were relevant regarding the increase in gene expression in OSCC. In addition, the up-regulation of PI3 and KRT17 might constitute potential candidate molecular biomarkers to diagnose patients with OSCC.

Atypical immunohistochemical patterns can complement the histopathological diagnosis of oral premalignant lesions

BACKGROUND

The histopathological diagnosis of oral premalignant lesions (OPLs) such as oral epithelial dysplasia (ED) and carcinoma in situ (CIS), as well as epithelial hyperplasia (EHP), is important for the early detection and precise treatment of oral squamous cell carcinoma. However, the standardization of detection and treatment by histological criteria alone remains challenging owing to the complicated and varied histology. We evaluated practically useful immunohistochemical (IHC) markers that might complement the histopathological diagnosis of OPLs.

METHODS

We re-evaluated the histopathological diagnoses and IHC patterns of Ki-67, TP53, CK13, and CK17 in 200 cases of OPLs and performed multiple logistic regression analyses for their predictive accuracy.

RESULTS

We identified and compared atypical IHC patterns in OPLs and in the normal epithelium. Ki-67 expression showed specific patterns in categorized OPLs as EHP, low-grade dysplasia (LED), high-grade dysplasia (HED), and CIS. Multiple logistic regression analyses in the quadrant categories revealed that EHP and CIS had high predictive accuracies of 90.1% and 96.2%, respectively, and in binary categories, combined EHP and LED versus combined HED and CIS showed predictive accuracies of 92.1% and 89.9%, respectively. Binominal logistic regression analysis between each quadrant category revealed satisfactory predictive accuracy of EHP vs. LED, LED vs. HED, and HED vs. CIS (75.2%, 78.9%, and 87.9%, respectively), and Ki-67 showed the highest adjusted odds ratio, followed by TP53.

CONCLUSION

The proposed atypical IHC patterns might serve as useful markers to supplement the morphological diagnosis of OPLs, and established IHC methods for Ki-67 and TP53 might provide stable results.

Intraepithelial CD163+ macrophages in tongue leukoplakia biopsy: A promising tool for cancer screening

OBJECTIVE

Oral leukoplakia has mixed and differing histopathological features, and it is thus difficult to reach an accurate histological diagnosis of oral leukoplakia based on a local biopsy alone. We recently demonstrated the significance of CD163⁺ macrophages in oral carcinogenesis. Herein we sought to determine whether CD163⁺ macrophages in biopsy specimens of oral leukoplakia help identify the overall histological nature of the lesion.

PATIENTS AND METHODS

Twenty-six patients with tongue leukoplakia who underwent a histological examination by both a preoperative local biopsy and consecutive total excision were enrolled. We evaluated clinicopathological factors and the expression of CD163⁺ macrophages based on a retrospective comparison of the histological diagnostic concordance between the biopsies and excisions.

RESULTS

Seventeen patients (diagnostic-agreement group) were diagnosed with squamous intraepithelial lesion based on both the biopsy and the excision. Nine patients (diagnostic-discrepancy group) were diagnosed with invasive cancer by excision, although invasive cancer was not observed in their biopsy specimens. Compared to the diagnostic-agreement group, the diagnostic-discrepancy group had more tongue leukoplakia with non-homogenous or high numbers of intraepithelial CD163⁺ macrophages.

CONCLUSION

The evaluation of intraepithelial CD163⁺ macrophages in local biopsy specimens from tongue leukoplakia patients is a promising tool for cancer screening.

Incorporation of differentiated dysplasia improves prediction of oral leukoplakia at increased risk of malignant progression

Oral leukoplakia is the most common oral potentially malignant disorder with a malignant transformation rate into oral squamous cell carcinoma of 1-3% annually. The presence and grade of World Health Organization defined dysplasia is an important histological marker to assess the risk for malignant transformation, but is not sufficiently accurate to personalize treatment and surveillance. Differentiated dysplasia, known from differentiated vulvar intraepithelial neoplasia, is hitherto not used in oral dysplasia grading. We hypothesized that assessing differentiated dysplasia besides World Health Organization defined (classic) dysplasia will improve risk assessment of malignant transformation of oral leukoplakia. We investigated a retrospective cohort consisting of 84 oral leukoplakia patients. Biopsies were assessed for dysplasia presence and grade, and the expression of keratins 13 (CK13) and 17, known to be dysregulated in dysplastic vulvar mucosa. In dysplastic oral lesions, differentiated dysplasia is as common as classic dysplasia. In 25 out of 84 (30%) patients, squamous cell carcinoma of the upper aerodigestive tract developed during follow-up. Considering only classic dysplasia, 11 out of 56 (20%) patients with nondysplastic lesions progressed. With the incorporation of differentiated dysplasia, only 2 out of 30 (7%) patients with nondysplastic lesions progressed. The risk of progression increased from 3.26 (Hazard ratio, p = 0.002) when only classic dysplasia is considered to 7.43 (Hazard ratio, p = 0.001) when classic and differentiated dysplasia are combined. Loss of CK13, combined with presence of dysplasia, is associated with greater risk of malignant progression (p = 0.006). This study demonstrates that differentiated dysplasia should be recognized as a separate type of dysplasia in the oral mucosa and that its distinction from classic dysplasia is of pathological and clinical significance since it is a strong (co)prognostic histopathological marker for oral malignant transformation. In oral lesions without dysplasia and retained CK13 staining the risk for progression is very low.

PD-L1 expression correlated with p53 expression in oral squamous cell carcinoma

Background

Programmed cell death ligand 1 (PD-L1) is an immune checkpoint molecule that attenuates the immune response. PD-L1 contributes to failed antitumor immunity; thereby, blockade of PD-L1 with monoclonal antibody enhances the immune response. Recently, it was reported that PD-L1 was regulated by protein 53 (p53). Besides, cytokeratin 17 (CK17) is thought to be a diagnostic marker of oral squamous cell carcinoma (OSCC). Our aim was to evaluate the correlation between the immunohistochemical expression of PD-L1, p53 and CK17 with clinicopathological characteristics and disease-specific survival in patients with OSCC.

Methods

A total of 48 patients with OSCC were included in this study. Immunohistochemical staining was performed to evaluate the correlation among the expressions of PD-L1, p53 and CK17, and furthermore the correlation among various clinicopathological factors, PD-L1, p53 and CK17.

Results

The positive rate of p53, CK17, PD-L1 (tumor cells) and PD-L1 (tumor-infiltrating lymphocytes) was 63.2%, 91.7%, 48.9% and 57.1%. A statistically significant correlation between p53 expression and T stage and TNM stage (p = 0.049, p = 0.03, respectively) was observed. Also, a statistically significant correlation between p53 and PD-L1 (TCs) expression (p = 0.0009) was observed. Five-year disease-specific survival rate was not significantly correlated with gender, TNM stage, p53 expression, PD-L1 expression and CK17 expression.

Conclusion

The expression of p53 and PD-L1 shows significantly positive correlation in oral squamous cell carcinoma in tumor cells. Also, a significant correlation between p53 expression and T stage and TNM stage was observed. No other significant correlation between PD-L1 staining or CK17 and clinical or pathologic characteristics was identified.

CD163+ macrophages infiltration correlates with the immunosuppressive cytokine interleukin 10 expression in tongue leukoplakia

Objective

Accumulating evidence suggests that macrophages are involved in the immunoediting of oral squamous cell carcinoma but the role of macrophages in oral carcinogenesis is unclear. We aimed to clarify the role of macrophages in oral leukoplakia, which is the most common oral potentially malignant disorder from immunotolerance viewpoint.

Materials and methods

The study included 24 patients who underwent surgical resection for tongue leukoplakia. The relationships between macrophage markers and clinicopathological factors were assessed. Conditioned medium was harvested from the CD163+ human monocytic leukaemia cell line, THP-1. The phenotypic alteration of human oral keratinocytes by the conditioned medium treatment was assessed using quantitative reverse transcription-polymerase chain reaction and enzyme-linked immunosorbent assay. Moreover, the clinical samples were evaluated using immunohistochemistry.

Results

Tongue leukoplakia tissues with high CD163+ macrophage infiltration were associated with significantly higher degrees of epithelial dysplasia, abnormal Ki-67 expression and cytokeratin13 loss when compared with the tissues with low CD163+ macrophage infiltration. In vitro, CD163+ THP-1 conditioned medium induced immunosuppressive molecules, especially interleukin-10 (IL-10) in human oral keratinocytes. The IL-10 expression levels showed significant positive correlations with not only the numbers of FOXP3+ regulatory T cells but also that of CD163+ macrophages.

Conclusions

In tongue leukoplakia, CD163+ macrophages infiltration correlates with immunosuppressive cytokine IL-10 expression.

Decreased cytokeratin 7 expression correlates with the progression of cervical squamous cell carcinoma and poor patient outcomes

AIM

To identify potential biomarkers for tumor progression and patient outcomes in cervical squamous cell carcinoma.

METHODS

We examined the expressions of CK7 and CK17 as potential markers of the squamo-columnar junction, and podoplanin as a basal cell marker using surgical and biopsy samples of patients in grade 3 cervical intraepithelial neoplasia (n = 30), operable invasive carcinoma (OP group, n = 53) and inoperable invasive carcinoma before radiotherapy and/or chemotherapy (RC group, n = 76).

RESULTS

The positive rates of CK7 and podoplanin in invasive carcinoma were significantly lower than those in grade 3 cervical intraepithelial neoplasia (P = 0.001, P < 0.0001). The positive rates of CK7 and podoplanin in the RC group were significantly lower than those in the OP group (P < 0.0001, P = 0.04), while CK17 expression showed significantly higher positivity in the RC group than in the OP group (P < 0.0001). Negative CK7 expression showed a potential impact on overall survival in early-stage patients. In the RC group, the prevalence of cases with post-therapeutic residual carcinoma cells was higher in the CK7-negative group than in the positive group (P = 0.003). We found that decreased expression of CK7 could be a prognostic factor in early-stage cervical cancer patients.

CONCLUSION

This result may provide strategies and suggestions for new treatment options and follow-up practices in managing patients with cervical cancer.

Dual role of KRT17: development of papillary renal cell tumor and progression of conventional renal cell carcinoma

Expression of KRT17 has been described in multi-layered epithelia as well as in tumors derived from these cells. In cancers arising from KRT17 negative single layered epithelia neo-expression of KRT17 has been associated with tumor progression. To obtain more insight into the biology of kidney cancers we have investigated KRT17 expression by immunohistochemistry in normal kidney, in papillary preneoplastic lesions and in 151 papillary and 692 conventional renal cell carcinomas placed on tissue microarray. We found a positive staining in ureteric bud and collecting duct cells in foetal kidney, in all papillary preneoplastic lesions and also in 77% of the 151 papillary renal cell tumors indicating a continuos KRT17 expression during tumor development. The neo-expression of KRT17 in conventional renal cell carcinomas, which derives from KRT17 negative proximal tubules showed a significant correlation with postoperative tumor relapse (RR=2.50; 95% CI=1.59-3.94; p<0.001). In conclusion, the continuous expression of KRT17 from emerging fetal kidney tubules and microscopic pre-neoplastic lesions towards papillary renal cell tumors and its neo-expression in aggressive growing conventional renal cell carcinomas reflects the multiple function of KRT17 in kidney cancers with distinct natural history. This should be taken into account in clinical managements and therapy.

Label-free tissue proteomics can classify oral squamous cell carcinoma from healthy tissue in a stage-specific manner

OBJECTIVES

No prognostic or predictive biomarkers for oral squamous cell carcinoma (OSCC) exist. We aimed to discover novel proteins, altered in OSCC, to be further investigated as potential biomarkers, and to improve understanding about pathways involved in OSCC.

MATERIALS AND METHODS

Proteomic signatures of seven paired healthy and OSCC tissue samples were identified using ultra-definition quantitative mass spectrometry, then analysed and compared using Anova, principal component analysis, hierarchical clustering and OPLS-DA modelling. A selection of significant proteins that were also altered in the serum from a previous study (PMID: 28632724) were validated immunohistochemically on an independent cohort (n = 66) to confirm immunopositivity and location within tumour tissue. Ingenuity Pathways Analysis was employed to identify altered pathways.

RESULTS

Of 829 proteins quantified, 257 were significant and 72 were able to classify healthy vs OSCC using OPLS-DA modelling. We identified 19 proteins not previously known to be upregulated in OSCC, including prosaposin and alpha-taxilin. KIAA1217 and NDRG1 were upregulated in stage IVa compared with stage I tumours. Altered pathways included calcium signalling, cellular movement, haematological system development and function, and immune cell trafficking, and involved NF-kB and MAPK networks.

CONCLUSIONS

We found a set of proteins reliably separating OSCC tumour from healthy tissue, and multiple proteins differing between stage I and stage IVa OSCC. These potential biomarkers can be studied and validated in larger cohorts.

Differentiated vulvar intraepithelial neoplasia (dVIN): the most helpful histological features and the utility of cytokeratins 13 and 17

Differentiated vulvar intraepithelial neoplasia (dVIN) is the precursor lesion of HPV-negative vulvar squamous cell carcinoma (VSCC). The histopathological diagnosis of dVIN can be challenging, as it often resembles vulvar non-neoplastic epithelial disorders (NNED), especially lichen sclerosus (LS). We aimed to establish the most specific and reproducible histological features of dVIN and assessed cytokeratin 13 (CK13) and cytokeratin 17 (CK17) immunohistochemistry as a diagnostic aid. Consecutive cases of dVIN (n = 180) and LS (n = 105) from the period 2010 to 2013 were reviewed using a checklist of histological features. Each feature was recorded as ‘present’ or ‘absent’ and statistical comparison (dVIN vs LS) was made. Interobserver agreement between two pairs of pathologists was assessed for a subset of cases of dVIN (n = 31) and LS and other NNED (n = 23). Immunohistochemistry with CK13, CK17, MIB1 and p53 was performed on dVIN, LS, and other NNED cases. Macronucleoli, features of disturbed maturation and angulated nuclei were significantly more common in dVIN than LS (p < 0.001). We found ‘substantial agreement’ for the diagnosis of dVIN (κ = 0.71). Macronucleoli and deep keratinisation had the highest agreement. In dVIN, the mean percentage of cells staining with CK13 was 15 and with CK17, this was 74. For LS, the mean percentage of cells staining with CK13 was 31, and with CK17, this was 41. By plotting receiver operating characteristic curves (ROC), an area under the curve (AUC) of 0.52 was obtained for CK13, and an AUC of 0.87 was obtained for CK17. The most helpful histological features for diagnosing dVIN were macronucleoli, features of disturbed maturation, and angulated nuclei. Increased CK17 expression may have promise for supporting dVIN diagnosis.

Cervical Adenoid Basal Carcinoma: Clinicopathologic Features of 9 Cases With Reference to CK17 and Ki-67 Expression

OBJECTIVE

The aims of this study were to clarify the histological features of adenoid basal carcinoma (ABC) and determine whether cytokeratin 17 (CK17) and Ki-67 can facilitate the differential diagnosis of ABC from squamous cell carcinoma (SCC).

MATERIALS AND METHODS

Nine cases of pure ABC were collected from the files of the Division of Pathology at the Zhejiang University Hospital Women's School of Medicine. For comparison, 20 cases of moderately to poorly differentiated cervical SCC, including 2 of basaloid SCC, were also retrieved from the same period. Blocks were recut, reread, and immunostained for CK17 and Ki-67.

RESULTS

Morphologically, ABCs were mainly composed of small basaloid cell nests and variable squamous differentiation foci. For immunohistochemical staining, 1 of 9 cases showed diffuse CK17 staining, 5 of 9 showed focal positive staining, and 3 of 9 showed negative staining in the basaloid cell area of ABC, whereas no CK17 expression was found in ABC squamous foci. Eighteen of the 20 invasive SCCs showed diffuse CK17 staining, and 2 showed focal staining. The Ki-67 proliferative index varied in different ABC areas, with a relatively high index in squamous differentiation foci and a low index in basaloid cell areas. In contrast, Ki-67 staining was unevenly intense in SCC.

CONCLUSIONS

Adenoid basal carcinoma had characteristic morphological features, and the differential diagnosis of ABC from SCC is usually simple, based on morphology. In select cases, when histological findings are equivocal, the loss of CK17 expression in the squamous differentiation area, and a lower Ki-67 index in basal cell foci support ABC diagnosis.

Verification of HE-based CTV in laryngeal and hypopharyngeal cancer using pan-cytokeratin

•

Currently clinical CTV margins lack evidence and need (histopathological) validation.

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Tumor outline on HE and pan-cytokeratin staining are comparable for laryngeal cancer.

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HE-based delineations can be used for histopathology based CTV-margin definition.

Background

For accurate target definition, we determined margins for the clinical target volume (CTV) for laryngeal and hypopharyngeal cancer in computed tomography (CT, 4.3 mm), magnetic resonance imaging (MR, 6.1 mm) and fluorodeoxyglucose (FDG)-positron emission tomography (PET, 5.2 mm). Previously, we used Hematoxylin-eosin (HE) stained whole-mount sections of total laryngectomy specimens as gold standard to define CTV margins. In the present study, we verified the HE-based tumor delineation with staining for pan-cytokeratin, specific for squamous cell carcinoma.

Methods

Twenty-seven patients with a T3/T4 laryngeal hypopharyngeal tumor were included. From each patient, a total laryngectomy specimen was obtained. Four subsequent 3-mm thick slices containing tumor were selected of which 4-µm thick whole-mount sections were obtained and stained with HE and for pan-cytokeratin CK-AE1/3. Tumors were microscopically delineated on both sections by an experienced head-and-neck pathologist. Tumor delineations were compared using the conformity index (CI) and the distance between both contours.

Results

The CI between HE-based and CK-AE1/3-based tumor delineations was 0.87. The maximum and 95th percentile (p95) extent of the HE-based tumor delineations from the CK-AE1/3-based tumor delineations were 1.7 mm and 0.7 mm, respectively. The maximum and p95 extent of the CK-AE1/3-based tumor delineations from the HE-based tumor delineations was 1.9 mm and 0.8 mm, respectively.

Conclusions

Histopathological assessment of tumor outline on standard HE-stained sections is comparable to microscopic tumor extent based on squamous cell specific pan-cytokeratin staining. Therefore, CTV margins based on HE based tumor contour will be adequate.

Immunohistochemical staining patterns of alpha-keratins in normal tissues from two reptile species: implications for characterization of squamous cell carcinomas

Background

Cytokeratins with epitopes in common with those of alpha (acidic and basic) mammalian keratins have been immunohistochemically demonstrated in the epidermis of reptiles. However, there are no reports of immunohistochemical staining patterns of alpha-keratins in other tissues from reptiles. Because the epithelial tumours usually retain the keratin patterns of their normal epithelial origin, it is necessary to know in advance these patterns in the major normal epithelia and organs. We used anti-alpha human keratin AE1 and AE3 monoclonal antibodies to study the staining patterns of alpha-keratins in the major normal epithelia and organs from two reptile species [the bearded dragon (Pogona vitticeps) and the loggerhead sea turtle (Caretta caretta)]. We also studied the immunolocalization of alpha-keratins in squamous cell carcinomas (SCCs) in a bearded dragon and two loggerhead turtles.

Results

Acidic alpha-keratin (AE1 positive) was detected in many of the epithelial tissues of the bearded dragons; however, the detection of basic alpha-keratin (AE3 positive) was much more limited. Alpha-keratins were detected in a greater number of tissues of loggerhead turtles compared with those observed in bearded dragons. In the bearded dragon SCC, all layers of the nests of neoplastic cells, including the cornified layer of the keratin pearls, were strongly reactive with the AE1 antibody. However, a weak reactivity using the AE3 antibody was detected in the basal and intermediate layers of these nests. In the cutaneous SCCs of both sea turtles, acidic alpha-keratin was detected in the basal and suprabasal layers, and in all of the invasive neoplastic cords, while basic alpha-keratin was mainly detected in the invasive neoplastic cords. The pattern observed in the metastases in both turtles consisted of immunohistological detection of acidic alpha-keratin in all metastatic foci, and limited or lack of detection of basic alpha-keratin.

Conclusions

This study provides, for the first time, information about the immunohistochemical staining patterns of alpha-keratins in normal tissues from bearded dragons and loggerhead sea turtles, and confirms the usefulness of AE1 and AE3 monoclonal antibodies in these reptile species. The use of these antibodies also contributed to a better characterization of SCCs in these species.

Cytokeratin 13, Cytokeratin 17, Ki-67 and p53 Expression in Upper Layers of Epithelial Dysplasia Surrounding Tongue Squamous Cell Carcinoma

Early detection of oral squamous cell carcinoma (OSCC) improves its prognosis and aids in selecting the appropriate treatment, which may also have a positive effect on quality of life. Early detection, therefore, is an important issue in the treatment of this disease. The purpose of this study was to investigate expression of cytokeratin 13 (CK13), CK17, Ki-67 and p53 as potential markers of tongue SCC. Five areas in 12 specimens were examined: the upper and lower layers of normal epithelium; those of dysplastic epithelial tissue surrounding the cancerous lesion; and the lesion itself. Strong expression of each of the following mRNAs and proteins was observed; CK13 in upper layers of normal epithelium; Ki-67 and p53 in lower layers of normal epithelium; CK13 and CK17 in upper layer of epithelial dysplasia; and CK17, Ki-67, and p53 in lower layer of epithelial dysplasia and cancerous lesions. These results indicate that the characteristic pattern of expression of CK13 and CK17 differs between normal and dysplastic oral epithelium. Oral epithelial dysplasia adjacent to OSCC has high malignant potential, and is similar to early-stage OSCC. This suggests that evaluation of these markers could be a useful secondary procedure for improving detection of early-stage OSCC.

Elevated expression of keratin 17 in oropharyngeal squamous cell carcinoma is associated with decreased survival

BACKGROUND

Overexpression of keratin 17 (K17) is highly associated with poor prognosis in squamous cell carcinoma (SCC) of the cervix. This study was performed to (1) determine whether K17 may be a prognostic biomarker in head and neck squamous cell carcinoma (HNSCC) and (2) to establish if K17 expression is associated with human papillomavirus (HPV) status.

METHODS

Immunohistochemical staining was performed for K17 of oral, oropharyngeal, and laryngeal SCCs, and normal oropharyngeal mucosa. The HPV status was determined using polymerase chain reaction (PCR).

RESULTS

Elevated K17 expression was significantly associated with an overall decreased patient survival (P = .02) and, more specifically, in patients with oropharyngeal SCC (P = .01). When controlling for HPV status and tumor location K17 was still a significant predictor of survival (P = .01).

CONCLUSION

Therefore, K17 is a novel prognostic biomarker of poor survival for patients with HNSCCs, controlling for anatomic site and HPV status.

Expression of protein arginine methyltransferase-5 in oral squamous cell carcinoma and its significance in epithelial-to-mesenchymal transition

Protein arginine methyltransferases (PRMT) 5, a member of type II arginine methyltransferases, catalyzes the symmetrical dimethylation of arginine residues on histone and non-histone substrates. Although the overexpression of PRMT5 has been reported in various cancers, its role in oral squamous cell carcinoma (OSCC) has not been elucidated. In the present study, we immunohistochemically examined the expression of PRMT5 in surgically resected oral epithelial dysplasia (OED, n = 8), oral intraepithelial neoplasia (OIN)/carcinoma in situ (CIS) (n = 11) and OSCC (n = 52) with or without contiguous OED lesions. In the normal epithelium, PRMT5 was weakly expressed in the cytoplasm of basal layer cells. In OED, OIN/CIS, and OSCC, its expression consistently and uniformly increased in the cytoplasm of dysplastic and cancer cells. Moreover, nuclear and cytoplasmic localization was detected in the invasive front of cancer cells, particularly in cases showing poor differentiation or aggressive invasion patterns. The concomitant nuclear and cytoplasmic expression of PRMT5 correlated with the loss of E-cadherin and cytokeratin 17, and the upregulation of vimentin, features that are both indicative of epithelial-to-mesenchymal transition. PRMT5 may play a role from early oncogenesis through to the progression of OSCC, particularly in the aggressive mode of stromal invasion.

SUOX is negatively associated with multistep carcinogenesis and proliferation in oral squamous cell carcinoma

Oral squamous cell carcinoma (OSCC) is the most common malignant tumor in the head and neck region. The aim of this study was to identify the key molecules and to elucidate the molecular mechanisms of OSCC carcinogenesis through a microarray analysis of RNA extracted from normal epithelium, dysplasia, and squamous cell carcinoma components. Out of molecules that showed changes in gene expression in the microarray analysis, we focused on Sulfite oxidase (SUOX), which correlated significantly with carcinogenic process and exhibited a stepwise decrease in expression. The expression of SUOX was evaluated in detail at the protein level using samples from 58 patients with cancer of the tongue, and correlating clinicopathological factors were also comprehensively examined. SUOX expression declined significantly from normal epithelium to dysplasia to squamous cell carcinoma components in line with carcinogenic process. With regard to squamous cell carcinoma, SUOX expression was significantly lower when T classification was high. Our findings indicated that SUOX is negatively associated with the progression and proliferation of tongue cancer, and suggest that SUOX may be a key molecule in tongue tumors.

Cytokeratin 17 mRNA as a prognostic marker of oral squamous cell carcinoma

Despite diagnostic and therapeutic advances, the 5-year survival rate of oral squamous cell carcinoma (OSCC) remains between 70–80% due to recurrences and secondary metastases to cervical lymph nodes. It is difficult to find these recurrences and metastases postoperatively, thus, careful follow-up is recommended. Cytokeratins (CKs) are intermediate filaments of the cytoskeleton and candidate prognostic biomarkers for OSCC, as they are overexpressed in OSCC compared with normal mucosa. The aim of the present study was to determine the relative levels of occurrence of 3 CK mRNA (CK17, CK19, CK20) transcripts in peripheral blood mononuclear cells (PBMC) using reverse transcription-quantitative polymerase chain reaction. The study comprised pre- and post-operative PBMC samples from 19 OSCC patients. In the good-prognosis group, 10 of 13 patients demonstrated reduced CK17 mRNA expression post-operatively, compared with pre-operative samples, conversely, only 3 of 6 patients in the poor-prognosis group had reduced post-operative CK17 mRNA expression. This difference was statistically significant (P<0.01). The disease-free survival rate of the group with reduced post-operative CK17 mRNA expression was significantly increased compared with the elevated CK17 mRNA group (P<0.01); however, the overall survival rates of the two groups were not significantly different. Neither CK19 mRNA nor CK20 mRNA were significantly expressed in the PBMC of OSCC patients. Overall, CK17 mRNA expression may be a useful prognostic biomarker for OSCC.

The overexpression of salivary cytokeratins as potential diagnostic biomarkers in head and neck squamous cell carcinomas

BACKGROUND

Cytokeratin (CK) intermediate filaments are demonstrated to have enormous potential in regulating cellular motility and cancer progression. There are more than 20 divergent CKs that have been identified, of which CK 8, 17, 18 and 19 are reported to be elevated in the tumour biopsies of head and neck cancer squamous cell carcinoma (HNSCC) patients. However, CK expression profiles in the saliva of HNSCC patients have not been investigated. We aim to investigate the mRNA expression profiles of CKs in saliva collected from healthy controls, HPV-negative and -positive HNSCC patients.

METHODS

Oral rinse samples were collected from 42 cancer-free healthy controls (age-matched) and patients who have been diagnosed with HPV-negative (n = 20) and -positive (n = 48) HNSCC.

RESULTS

Here, we report that the mRNA expression profiles of CKs differed in saliva collected from healthy controls and HNSCC patients. The mRNA expression levels of CK 8 and 18 were significantly elevated in saliva collected from HPV-negative HNSCC patients; whilst, CK 17 and 19 were expressed at a higher mRNA level in saliva collected from HPV-positive HNSCC patients compared to healthy controls. Importantly, receiver operating characteristic (ROC) analysis showed salivary CK 8 and 18 to have superior sensitivity and specificity in discriminating the HPV-negative HNSCC patients from healthy controls (80% and 86%) as well as between HPV-negative and -positive HNSCC patients (75% and 81%).

CONCLUSION

In summary, we have demonstrated that an aberrant expression of salivary CKs may serve as a potential non-invasive diagnostic biomarker in HNSCC.

GLI-mediated Keratin 17 expression promotes tumor cell growth through the anti-apoptotic function in oral squamous cell carcinomas

PURPOSE

Keratin 17 (KRT17) has been suggested as a potential diagnostic marker of squamous cell carcinoma including oral squamous cell carcinoma (OSCC). The current study was conducted to clarify the function of KRT17 and its expression mechanism in OSCC.

METHODS

Immunohistochemical analyses were carried out to examine the expression of KRT17, GLI family zinc finger (GLI)-1, GLI-2, or cleaved caspase-3 in OSCCs. The expression of KRT17, GLI-1, or GLI-2 was investigated among OSCC cell lines, and the effects of loss-of-function of KRT17 or GLI, using siRNA or inhibitor, on the cell growth of the OSCC cell line HSC-2 particularly with respect to apoptosis were examined.

RESULTS

Immunohistochemical analyses of tissue specimens obtained from 78 OSCC patients revealed that KRT17 was not observed in non-tumor regions but was strongly expressed at high frequencies in tumor regions. Knockdown of KRT17 increased the number of cleaved caspase-3-positive cells, leading to the reduction of cell number. Loss-of-function of GLI-1 or GLI-2 also increased the cell numbers of apoptotic cells positive for staining of Annexin-V and propidium iodide (PI) and the terminal deoxynucleotidyl transferase dUTP-biotin nick-end labeling (TUNEL) method, and induced DNA fragmentation. This inhibitory effect on cell growth was partially rescued by exogenous KRT17 expression. In the KRT17-positive regions in OSCCs, GLI-1 or GLI-2 was frequently detected, and the number of cells with cleaved caspase-3 positive was decreased.

CONCLUSIONS

KRT17 promotes tumor cell growth, at least partially, through its anti-apoptotic effect as a result of the KRT17 overexpression by GLIs in OSCC.

Cytokeratin 17 and Ki-67: Immunohistochemical markers for the differential diagnosis of keratoacanthoma and squamous cell carcinoma

The clinical and histopathological distinction between keratoacanthoma (KA) and squamous cell carcinoma (SCC) is essential, but frequently difficult to make. The utility of CK17 and Ki-67 expression in distinguishing between KA and SCC was investigated. Immunohistochemical staining patterns for CK17 and Ki-67 were evaluated in 24 KA and 27 SCC cases. The pattern of staining was evaluated as central, peripheral or diffuse, according to the basal/peripheral and suprabasal/central cell staining of tumor lobules. The sensitivity and specificity of the central CK17 staining pattern in the identification of KA were 92 and 70%, respectively. Additionally, the sensitivity and specificity of the diffuse Ki-67 staining pattern in the identification of SCC were 81 and 100%, respectively. The results of the present study suggest that a diffuse Ki-67 staining pattern may be used to diagnose SCC, while a central CK17 staining pattern indicates KA. However, the KA-like SCC cases exhibited mixed patterns, which limits the effectiveness of these markers.

Cancer stem cell, cytokeratins and epithelial to mesenchymal transition markers expression in oral squamous cell carcinoma derived from ortothopic xenoimplantation of CD44high cells

Oral squamous cell carcinoma (OSCC) is the most prevalent neoplasia of oral cavity worldwide and prognosis remains unchanged in decades. Recently, different authors reported that head and neck squamous cell carcinomas have a subpopulation of tumor initiating cells that apparently correspond to cancer stem cells (CSC) and are also responsible for tumor growth and metastasis. The purpose of the present study was to investigate the microscopic and phenotypic characteristics of OSCC tumors induced after orthotopic xenoimplantation of SCC9^WT cell line and CSC-enriched subpopulation isolated from SCC9 cell line based on high expression of the putative CSC marker CD44. Different numbers of FACS-sorted SCC9 CD44^high and CD44^low cells as well as SCC9^WT (wild type) were transplanted into the tongue of BALB/C nude (NOD/SCID) mice to evaluate their tumorigenic potential. Sixty days post-induction, tumors were morphologically characterized and immunostained for CSC markers (CD44, Nanog and Bmi-1), epithelial-mesenchymal transition (Snail, Slug) and epithelial differentiating cell markers (cytokeratins 4, 13, 15, 17 and 19), as well as E-cadherin and β-catenin. The data presented here shows that SCC9 CD44^high cells have higher ability to form tumors than SCC9 CD44^low cells, even when significantly lower numbers of SCC9 CD44^high cells were transplanted. Immunoassessment of tumors derived from SCC9 CD44^high cells revealed high expression of cytokeratin CK19, β-catenin, E-cadherin and CD44, and negative or low expression of CK17, CK4, CK15, CK13, Nanog, Bmi-1, Snail and Slug. While tumors derived from SCC9^WT showed high expression of CK17, CK19, CD44, Nanog, Bmi-1, Snail and Slug, and negative or low expression of CK4, CK15, CK13, β-catenin and E-cadherin. Thus, SCC9 CD44^high cells were highly tumorigenic, capable of originating heterogeneous tumors and these tumors have a immunohistochemical profile different from those formed by the wild type cell line.

Quantitative Proteomic Profiling the Molecular Signatures of Annexin A5 in Lung Squamous Carcinoma Cells

Lung cancer remains the leading cancer killer around the world. It's crucial to identify newer mechanism-based targets to effectively manage lung cancer. Annexin A5 (ANXA5) is a protein kinase C inhibitory protein and calcium dependent phospholipid-binding protein, which may act as an endogenous regulator of various pathophysiological processes. However, its molecular mechanism in lung cancer remains poorly understood. This study was designed to determine the mechanism of ANXA5 in lung cancer with a hope to obtain useful information to provide a new therapeutic target. We used a stable isotope dimethyl labeling based quantitative proteomic method to identify differentially expressed proteins in NSCLC cell lines after ANXA5 transfection. Out of 314 proteins, we identified 26 and 44 proteins that were down- and up-regulated upon ANXA5 modulation, respectively. The IPA analysis revealed that glycolysis and gluconeogenesis were the predominant pathways modulated by ANXA5. Multiple central nodes, namely HSPA5, FN1, PDIA6, ENO1, ALDOA, JUP and KRT6A appeared to occupy regulatory nodes in the protein-protein networks upon ANXA5 modulation. Taken together, ANXA5 appears to have pleotropic effects, as it modulates multiple key signaling pathways, supporting the potential usefulness of ANXA5 as a potential target in lung cancer. This study might provide a new insight into the mechanism of ANXA5 in lung cancer.

Lack of Utility of Cytokeratins in Differentiating Pseudocarcinomatous Hyperplasia of Granular Cell Tumors from Oral Squamous Cell Carcinoma

Granular cell tumor (GCT) of the oral cavity is a benign lesion. Half of oral GCTs demonstrate pseudocarcinomatous hyperplasia (PCH) of the mucosa which can mimic invasive islands of oral squamous cell carcinoma (SCC). Such similarity can be confusing when diagnosing or evaluating the two conditions, potentially leading to misdiagnosis or misclassification. Indeed, several misdiagnosed cases of oral GCT have been reported in the literature as OSCC or malignant oral GCT that resulted in unnecessary aggressive treatment for the affected patients. The aim of this study was to investigate if the cytokeratin pattern of the PCH can help in differentiating GCT from oral SCC. To distinguish between these two entities, we examined 12 patient specimens of oral GCT-PCH and oral SCC histologically and via immunohistochemistry (IHC) for CK13, CK17 and P75. The results suggest that the cytokeratin profile of PCH is similar to that of oral SCC. Therefore, consideration of IHC findings for epithelial markers alone may lead to erroneous diagnosis; thus, the presence of the granular tumor underneath the PCH and its immunopositivity for P75 or other neural definition markers can be essential to identify the underlying tumor and exclude oral SCC. Finally we recommend more studies on the molecular biology of PCH to understand how it can mimic oral SCC histologically without harboring its malignant phenotype clinically, which could have significant translational potential for understanding invasive oral SCC.

Clinicopathological Significance of Vimentin and Cytokeratin Protein in the Genesis of Squamous Cell Carcinoma of Cervix

Cervical cancer is one of the commonest types of cancers worldwide especially in developing countries. Intermediate filaments protein family has shown a role in the diagnosis of various cancers, but a few studies are available about the vimentin and cytokeratin roles in the cervical cancer. This case control study aimed to interpret the expression of vimentin and cytokeratin proteins in the development and progression of cervical cancer and its correlation with clinicopathological features. The cytoplasmic expression of vimentin was observed in 40% of cases, but not in inflammatory lesions of cervix. It was noticed that vimentin expression was increasing significantly with high grade of the tumour. Cytokeratin expression was observed in 48.33% and it was noticed that the expression was 62.5% in well differentiated (G1), 45% in moderately differentiated (G2), and 41.66% in poorly differentiated carcinoma, yet statistically insignificant. The expression of vimentin and cytokeratin proteins was not significantly associated with age groups. The current findings concluded a possible role of vimentin in the development and progression of cervical cancer and vimentin marker will be useful in the diagnosis and grading of cervical cancer.