Cancer stem cells and field cancerization of Oral squamous cell carcinoma

Fluorescence Visualization-Guided Surgery Improves Local Control for Mandibular Squamous Cell Carcinoma

BACKGROUND

Local recurrence is common in mandibular squamous cell carcinoma (SCC). Fluorescence visualization is a noninvasive technology that can detect oral epithelial dysplasia around mandibular SCC, and it can potentially reduce local recurrence.

PURPOSE

The purpose of this study was to measure and compare local control (LC) between fluorescence visualization-guided surgery (FVS) and conventional surgery for patients with Stages I or II mandibular SCC.

STUDY DESIGN, SETTING, SAMPLE

This retrospective cohort study was conducted at Tokyo Dental College, Chiba Hospital, or Chiba Dental Center. The medical records of mandibular SCC patients from 2000 to 2021 were analyzed. Patients from any sex and 18 years of age or older with complete records who received surgery for mandibular SCC in the early stages were included in this study.

PREDICTOR VARIABLE

The predictor variable was operative treatment and was divided into 2 groups, conventional or FVS.

MAIN OUTCOME VARIABLES

The outcome variable is 5-year LC defined as no recurrence at or within 20 mm of the surgical site.

COVARIATES

Covariates included demographic variables of age, sex, clinical and pathological characteristics, forms of resection, lifestyle, and quality of life.

ANALYSES

Data analysis was performed by carrying out χ2 tests. Survival outcome was performed by the Kaplan-Meier method, which was used to calculate and stratify the log-rank test; P values <.05 indicated statistical significance.

RESULTS

This study sample was composed of 56 subjects with a mean age of 68.5 years old (standard deviation 13.7), and 33 (58.9%) were female. There were 36 (64.3%) and 20 (35.7%) subjects in the conventional and FVS groups. The characteristics and quality of life did not differ significantly between the 2 groups. Five-year LC with FVS was statistically significantly higher than conventional surgery (P = .04, 94.4 vs 77.2%). Multivariate analysis for LC rate only identified FVS (P = .004; hazard ratio = 0.11, 95% confidence interval = 0.46, 0.88).

CONCLUSION AND RELEVANCE

On mandibular SCC, LC was 94.4% in FVS versus 77.2% in conventional surgery. For mandibular SCC at stages I and II, FVS was associated with improved LC.

EphA2 promotes the transcription of KLF4 to facilitate stemness in oral squamous cell carcinoma

Ephrin receptor A2 (EphA2), a member of the Ephrin receptor family, is closely related to the progression of oral squamous cell carcinoma (OSCC). Cancer stem cells (CSCs) play essential roles in OSCC development and occurrence. The underlying mechanisms between EphA2 and CSCs, however, are not yet fully understood. Here, we found that EphA2 was overexpressed in OSCC tissues and was associated with poor prognosis. Knockdown of EphA2 dampened the CSC phenotype and the tumour-initiating frequency of OSCC cells. Crucially, the effects of EphA2 on the CSC phenotype relied on KLF4, a key transcription factor for CSCs. Mechanistically, EphA2 activated the ERK signalling pathway, promoting the nuclear translocation of YAP. Subsequently, YAP was bound to TEAD3, leading to the transcription of KLF4. Overall, our findings revealed that EphA2 can enhance the stemness of OSCC cells, and this study identified the EphA2/KLF4 axis as a potential target for treating OSCC.

SOX2 promotes a cancer stem cell-like phenotype and local spreading in oral squamous cell carcinoma

Emerging evidence shows that oral squamous cell carcinoma (OSCC) invasiveness can be attributed to a small subpopulation of cancer stem cells (CSCs) in the bulk of the tumor. However, the presence of CSCs in the OSCC close resection margins is still poorly unexplored. Here, we found that BMI1, CD44, SOX2, OCT4, UBE2C, CXCR4 CSCs marker genes are significantly upregulated, while IGF1-R, KLF4, ALDH1A1, CD133, FAM3C are downregulated in the tumor core vs healthy mucosa of 24 patients with OSCC. Among these, SOX2 appears also upregulated in the tumor close margin vs healthy mucosa and this significantly correlates with tumor size and lymph node compromise. In vitro analyses in CAL27 and SCC15 tongue squamous cell carcinoma cell lines, show that SOX2 transient knockdown i) promotes the mesenchymal-to-epithelial transition, ii) smooths the invasiveness, iii) attenuates the 3D tumor sphere-forming capacity, and iv) partially increases the sensitivity to cisplatin treatment. Overall, our study highlights that the OSCC close margins can retain CSC-specific markers. Notably, SOX2 may represent a useful CSCs marker to predict a more aggressive phenotype and a suitable target to prevent local invasiveness.

Mortality patterns of patients with tonsillar squamous cell carcinoma: a population-based study

Objective

Tonsillar squamous cell carcinoma (TSCC) and second primary malignancies (SPMs) are the most common causes of mortality in patients with primary TSCC. However, the competing data on TSCC-specific death (TSD) or SPM-related death in patients with TSCC have not been evaluated. This study aimed to analyze the mortality patterns and formulate prediction models of mortality risk caused by TSCC and SPMs.

Methods

Data on patients with a first diagnosis of TSCC were extracted as the training cohort from the 18 registries comprising the Surveillance, Epidemiology, and End Results (SEER) database. A competing risk approach of cumulation incidence function was used to estimate cumulative incidence curves. Fine and gray proportional sub-distributed hazard model analyses were performed to investigate the risk factors of TSD and SPMs. A nomogram was developed to predict the 5- and 10-year risk probabilities of death caused by TSCC and SPMs. Moreover, data from the 22 registries of the SEER database were also extracted to validate the nomograms.

Results

In the training cohort, we identified 14,530 patients with primary TSCC, with TSCC (46.84%) as the leading cause of death, followed by SPMs (26.86%) among all causes of death. In the proportion of SPMs, the lungs and bronchus (22.64%) were the most common sites for SPM-related deaths, followed by the larynx (9.99%), esophagus (8.46%), and Non-Melanoma skin (6.82%). Multivariate competing risk model showed that age, ethnicity, marital status, primary site, summary stage, radiotherapy, and surgery were independently associated with mortality caused by TSCC and SPMs. Such risk factors were selected to formulate prognostic nomograms. The nomograms showed preferable discrimination and calibration in both the training and validation cohorts.

Conclusion

Patients with primary TSCC have a high mortality risk of SPMs, and the competing risk nomogram has an ideal performance for predicting TSD and SPMs-related mortality. Routine follow-up care for TSCC survivors should be expanded to monitor SPMs.

Proliferative verrucous leukoplakia: a case report of multiple metachronous oral verrucous carcinoma

Proliferative verrucous leukoplakia (PVL) is a distinct progressive and multi-focal form of oral leukoplakia, not associated with the traditional risk factors (ie, tobacco and alcohol consumption). The incidence of oral squamous cell carcinoma in PVL patients is high. Here, we describe the case of a patient affected by PVL, who developed two metachronous oral verrucous carcinomas at different sites of the oral mucosa. Owing to the high risk of multiple oral squamous cell carcinoma, periodical clinical and histopathological follow-up is mandatory and should continue lifelong.

Flavinated SDHA underlies the change in intrinsic optical properties of oral cancers

The molecular basis of reduced autofluorescence in oral squamous cell carcinoma (OSCC) cells relative to normal cells has been speculated to be due to lower levels of free flavin adenine dinucleotide (FAD). This speculation, along with differences in the intrinsic optical properties of extracellular collagen, lies at the foundation of the design of currently-used clinical optical detection devices. Here, we report that free FAD levels may not account for differences in autofluorescence of OSCC cells, but that the differences relate to FAD as a co-factor for flavination. Autofluorescence from a 70 kDa flavoprotein, succinate dehydrogenase A (SDHA), was found to be responsible for changes in optical properties within the FAD spectral region, with lower levels of flavinated SDHA in OSCC cells. Since flavinated SDHA is required for functional complexation with succinate dehydrogenase B (SDHB), decreased SDHB levels were observed in human OSCC tissue relative to normal tissues. Accordingly, the metabolism of OSCC cells was found to be significantly altered relative to normal cells, revealing vulnerabilities for both diagnosis and targeted therapy. Optimizing non-invasive tools based on optical and metabolic signatures of cancers will enable more precise and early diagnosis leading to improved outcomes in patients.

A snapshot of miRNAs in oral squamous cell carcinoma: Difference between cancer cells and corresponding normal cells

Oral squamous cell carcinoma (OSCC) constitutes the most aggressive tumors of the oral cavity and is one of the leading causes of cancer mortality worldwide. Although recent clinical treatment strategies have improved the survival rate, the outcome of OSCC patients still remains dismal because of the lack of efficient diagnostic and treatment tools. As one of the main actors of OSCC scenario, microRNAs (miRNAs) are involved in triggering, progression and metastasis through the regulation of various cancer-related signaling pathways. Identification followed by precise study of the biology and mechanism of action of miRNAs will greatly help to provide valuable insights regarding OSCC development and can be considered as an anti-OSCC target. In the current review, we have provided a focused summary of the latest published papers on the role of miRNAs in apoptosis, cell cycle, proliferation, EMT and metastasis of OSCC as well as the role of long noncoding RNAs in the modulation of miRNAs in OSCC.

Flavinated SDHA Underlies the Change in Intrinsic Optical Properties of Oral Cancers

The molecular basis of reduced autofluorescence in oral squamous cell carcinoma (OSCC) cells relative to normal cells has been speculated to be due to lower levels of free flavin adenine dinucleotide (FAD). This speculation, along with differences in the intrinsic optical properties of extracellular collagen, lie at the foundation of the design of currently-used clinical optical detection devices. Here, we report that free FAD levels may not account for differences in autofluorescence of OSCC cells, but that the differences relate to FAD as a co-factor for flavination. Autofluorescence from a 70 kDa flavoprotein, succinate dehydrogenase A (SDHA), was found to be responsible for changes in optical properties within the FAD spectral region with lower levels of flavinated SDHA in OSCC cells. Since flavinated SDHA is required for functional complexation with succinate dehydrogenase B (SDHB), decreased SDHB levels were observed in human OSCC tissue relative to normal tissues. Accordingly, the metabolism of OSCC cells was found to be significantly altered relative to normal cells, revealing vulnerabilities for both diagnosis and targeted therapy. Optimizing non-invasive tools based on optical and metabolic signatures of cancers will enable more precise and early diagnosis leading to improved outcomes in patients.

A computational model for the cancer field effect

Introduction

The Cancer Field Effect describes an area of pre-cancerous cells that results from continued exposure to carcinogens. Cells in the cancer field can easily develop into cancer. Removal of the main tumor mass might leave the cancer field behind, increasing risk of recurrence.

Methods

The model we propose for the cancer field effect is a hybrid cellular automaton (CA), which includes a multi-layer perceptron (MLP) to compute the effects of the carcinogens on the gene expression of the genes related to cancer development. We use carcinogen interactions that are typically associated with smoking and alcohol consumption and their effect on cancer fields of the tongue.

Results

Using simulations we support the understanding that tobacco smoking is a potent carcinogen, which can be reinforced by alcohol consumption. The effect of alcohol alone is significantly less than the effect of tobacco. We further observe that pairing tumor excision with field removal delays recurrence compared to tumor excision alone. We track cell lineages and find that, in most cases, a polyclonal field develops, where the number of distinct cell lineages decreases over time as some lineages become dominant over others. Finally, we find tumor masses rarely form via monoclonal origin.

Targeting PCSK9 reduces cancer cell stemness and enhances antitumor immunity in head and neck cancer

Proprotein convertase subtilisin/kexin type 9 (PCSK9) has been demonstrated to play a critical role in regulating cholesterol homeostasis and T cell antitumor immunity. However, the expression, function, and therapeutic value of PCSK9 in head and neck squamous cell carcinoma (HNSCC) remain largely unexplored. Here, we found that the expression of PCSK9 was upregulated in HNSCC tissues, and higher PCSK9 expression indicated poorer prognosis in HNSCC patients. We further found that pharmacological inhibition or siRNA downregulating PCSK9 expression suppressed the stemness-like phenotype of cancer cells in an LDLR-dependent manner. Moreover, PCSK9 inhibition enhanced the infiltration of CD8⁺ T cells and reduced the myeloid-derived suppressor cells (MDSCs) in a 4MOSC1 syngeneic tumor-bearing mouse model, and it also enhanced the antitumor effect of anti-PD-1 immune checkpoint blockade (ICB) therapy. Together, these results indicated that PCSK9, a traditional hypercholesterolemia target, may be a novel biomarker and therapeutic target to enhance ICB therapy in HNSCC.

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

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

Clinical and prognostic features of multiple primary cancers with oral squamous cell carcinoma

OBJECTIVE

To characterize the epidemiological, clinical, and prognostic features of multiple primary cancers (MPC) following oral squamous cell carcinoma (OSCC).

DESIGN

Data from the Surveillance, Epidemiology, and End Results Program database were analyzed to determine the standardized incidence ratio (SIR) of multiple subsequent sites, difference in clinical and prognostic features between MPC and single primary OSCC.

RESULTS

The sites with the highest SIRs were the oral cavity (SIR = 69.48), other oral cavity and pharynx (SIR=55.46), pharynx (SIR=39.21), tonsils (SIR=33.52), trachea (SIR=33.24), esophagus (SIR=18.00), and larynx (SIR=13.12). The 5- and 10-year survival rates for single primary OSCC were 57.9% (95% CI: 56.7-59.2%) and 47.1% (95% CI: 45.7-48.6%), respectively, while those for MPC were 66.9% (95% CI: 64.6-69.4%) and 42.2% (95% CI: 39.5-45.2%), respectively. The mean age of MPC patients was significantly higher than that of single primary OSCC patients. MPC are more common in the gums and other sites of the oral cavity, and more likely to be detected in early TNM stage and pathological grade. Age, site, T-stage, and N-stage were significantly associated with prognosis of MPC.

CONCLUSIONS

Significant differences in clinical and prognostic features were found between MPC and single primary OSCC. Considering MPC has a poor long-term prognosis, it is necessary to identify MPC and single primary OSCC early.

Occurrence of field cancerization in clinically normal oral mucosa: A systematic review and meta-analysis

OBJECTIVE

The purpose was to describe whether there are field cancerization (FC) indicators in clinically normal mucosa opposite to primary oral squamous cell carcinoma (OSCC).

METHODS

A search of the Cochrane Library, PubMed, Embase, Web of Science, Scopus, and Livivo databases was performed on June 12, 2022, which retrieved 152 records without duplicates. Studies that analyzed FC in biopsies in clinically normal tissue opposite to primary OSCC were included. The search was conducted under the PRISMA guideline and the protocol was registered in PROSPERO (CRD42017077125).

RESULTS

Eight articles with 302 patients were included, 192 men and 110 women, mean age 57.1 years. Most patients had deleterious habits. All studies performed histopathological confirmation of OSCC and biopsies were obtained the clinically normal mirror mucosa. The meta-analysis carried out with eight studies. The studies showed 57.3 % of cases with histopathological changes of clinically normal mucosa opposite to primary OSCC (Confidence interval 95 %, 0.443-0.703; heterogeneity: Q value 18.715; I² 73.284 %; n = 205). p53 and Ki-67 immunohistochemical analysis may be predictive for detecting changes. There was p53 immunoexpression in 41.3 % of cases (p = 0.872) (n = 55), ki-67 immunoexpression (< 20 %) in 68 % (p = 0.001) (n = 97) and ki-67 immunoexpression (> 20 %) in 28.4 % of cases (p = 0.000) (n = 110).

CONCLUSIONS

The findings suggest that FC can occur, and there are histopathological changes in clinically normal tissue opposite to primary OSCC. Nevertheless, the review showed that more longitudinal studies on FC are needed to draw a conclusive indication of the occurrence of FC in oral tissues opposite to OSCC.

Prognostic and clinicopathological significance of cytocapsular tubes in oral squamous cell carcinoma

BACKGROUND

Cytocapsular tubes (CTs) provide membranous channels for cancer cells interconnection and multidirectional locomotion, which facilitate cancer cell transportation and metastasis. However, the clinicopathological significance of CTs has not been documented in oral squamous cell carcinoma (OSCC). Herein, we aimed to identify CTs and assess their clinicopathological significance in OSCC.

METHODS

Operetta CLS™ high-content analysis system was used to detect the CTs originated from OSCC cells cultured in a 3D Matrigel matrix. Then, pan-cadherin and γ-actin immunostaining were performed to identify CTs in 4NQO-induced murine OSCC tissues, OSCC xenografts and 88 human primary OSCC samples. Finally, the prognostic value and clinicopathological significance of CTs in OSCC were further examined by using the Kaplan-Meier method and Cox regression analysis.

RESULTS

CTs were observed in OSCC cells in a 3D Matrigel matrix. In vivo, CTs were frequently identified in 4NQO-induced murine OSCC tissues, OSCC xenografts and human primary OSCC samples. CTs density was significantly associated with T stage, lymph node metastasis, differentiation, invasive depth, tumor budding, TNM stage and tumor recurrence. Importantly, the high-CTs density indicated a decreased overall survival (OS) and progression-free survival (PFS) in OSCC patients. Cox regression models showed that CTs could serve as a prognostic factor for OS and PFS.

CONCLUSION

CTs, which are correlated with the cell migration and invasion, can be readily identified in OSCC and appear to be a novel biomarker for patients at risk of metastasis.

Malignant transformation of oral epithelial dysplasia in Southwest Finland

Oral epithelial dysplasia (OED) is considered a risk for oral squamous cell carcinoma (OSCC). A meta-analysis estimated a mean malignant transformation rate of 12.1% (95% CI 8.1-17.9). The main target of this study was to define how many OED patients develop OSCC in the hospital district of Southwest Finland. A total of 571 patients diagnosed with OED were identified. Their potential subsequent diagnosis of OSCC was derived from the Finnish Cancer Registry. The risk of OSCC development in OED patients was compared with that of the general population without OED. During a mean follow-up of 5.5 (range 0.1-29.0) years 10.9% of OED patients developed OSCC. OED patients had a 44.7-fold higher risk (95% CI 34.4-56.7) of developing OSCC than the general population. The risk was at its highest within two years of OED diagnosis. OED patients in Southwest Finland have a significantly increased risk of developing OSCC relative to the general population, especially within the first two years of dysplasia diagnosis.

A Novel Overall Survival Nomogram Prediction of Secondary Primary Malignancies after Hypopharyngeal Cancer: A Population-Based Study

Objectives

We aimed to construct a nomogram for predicting the overall survival (OS) of patients with secondary primary malignancies (SPMs) after hypopharyngeal cancer (HPC).

Methods

613 HPC patients were included in the Surveillance, Epidemiology, and End Results (SEER) database between 2000 and 2018, which were divided into training and validation cohorts. The least absolute shrinkage and selection operation (LASSO) and stepwise Cox regression were used to determine the variables by which a nomogram model was established.

Results

After the LASSO and stepwise Cox regression analysis, the age, year of diagnosis, sites of SPMs, SEER stage of SPMs, surgery for SPMs, and radiotherapy for SPMs were included for model establishment. The ROC curve showed good discrimination for the 3- and 5-year AUC values in the training (0.774 and 0.779, respectively) and validation (0.758 and 0.763, respectively) cohorts. The calibration curve indicated good prognostic accuracy, especially in the 5-year survival prediction for this model. The DCA also demonstrated clinical efficacy over a wide range of threshold probabilities. Lastly, the risk group classified by the individual nomogram values showed significantly different survival outcomes in both training and validation cohorts.

Conclusions

We constructed a nomogram to predict the OS of SPMs after HPC with good clinical values.

Clinical and Histological Prognostic Factors of Recurrence and Malignant Transformation in a Large Series of Oral Potentially Malignant Disorders

Background

Oral potentially malignant disorders (OPMDs) represent a heterogeneous set of different histological lesions, characterized by the capacity to transform in oral squamous cell carcinoma (OSCC). Despite optimal surgical treatment, approximately 20%–30% of OPMDs may evolve into OSCC. No clear clinical/histological factors are able to identify OPMDs at higher risk of malignant transformation.

Materials and Methods

We considered surgically treated patients with a diagnosis of OPMDs, enrolled from 1996 to 2019 at ASST Spedali Civili of Brescia without a diagnosis of OSCC within the previous 2 years. Clinical and histological characteristics were recorded. Outcomes of interest were recurrence-free survival (RFS), defined as the time from surgery for primary OPMD to any relapse of OPMD or malignant transformation, whichever occurred first, and carcinoma-free survival (CFS), defined as the time from surgery for OPMD to malignant transformation.

Results

We retrospectively reviewed 106 OPMDs cases. Median age at first diagnosis was 64 years old (IQR = 18.75); female patients comprise 51.9% of the cases. During a median follow-up of 30.5 months (IQR = 44), in 23.5% of patients, malignant transformation occurred. RFS at 1, 5, and 10 years was 92.4%, 60.9%, and 43.2%, respectively. Female sex and history of previous OSCC were independent risk factors for RFS. CFS at 1, 5, and 10 years of follow-up was 97.1%, 75.9%, and 64.4%, respectively. Previous OSCC was an independent risk factor for CFS.

Conclusions

In this large series of OPMDs, only previous diagnosis of OSCC was a prognostic factor for further OSCC occurrence. Given the lack of additional clinical/pathological prognostic factors, we advocate further studies into molecular characterization of OPMDs to better stratify the risk of malignant transformation.

Surgical Margins for Ameloblastoma in Dogs: A Review With an Emphasis on the Future

Ameloblastoma is a benign epithelial odontogenic tumor with the capacity to aggressively invade the surrounding bone. Surgical removal of the tumor can result in extended disease-free interval (cure). However, controversy surrounds the most appropriate surgical margin required to prevent local recurrence while simultaneously minimizing morbidity. En bloc excisional surgery carries the risk of major complications such as mandibular drift, hemorrhage, and oronasal fistula formation. Conservative therapy without a safety margin reduces potential morbidity but is likely to result in local recurrence. No reliable rate, nor time to recurrence, is documented but may be as high as 91% with conservative therapy. Conversely, surgery with a 10- to 20-mm margin is associated with a 0–4.6% recurrence rate. There is no documented difference in the recurrence rate with a 10- vs. 20-mm margin. The correlation of the histologic margin with the recurrence rate following excisional surgery has not determined a required histologic safety margin. Rather, no local recurrence occurs despite narrow or incomplete margins. Thus, pathologic margins > 0 mm may be sufficient to prevent local recurrence or recurrence may be protracted. Accordingly, a narrow (5–10 mm) gross surgical margin may be the most appropriate. Additional research is required for confirmation, and only level 4 evidence on safety margins has been achieved thus far. Future work should focus on defining the extension of neoplastic cells past the demarcation of ameloblastoma on variable diagnostic imaging modalities as well as determining the recurrence rate with various surgical and histologic safety margins.

Clinical significance of ALDH1A1 expression and its association with E-cadherin and N-cadherin in resected large cell neuroendocrine carcinoma

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It is the first study on the effect of ALDH1A1 on the prognosis of LCNEC. And we found ALDH1A1 acts as a favorable independent prognostic factor in LCNEC.

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We investigated the relationship between ALDH1A1 and EMT markers (E-cadherin/ N-cadherin) and found that ALDH1A1 is associated with epithelial phenotype marker E-cadherin in LCNEC.

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Our sample size is large and simple and the clinical data is complete.

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The exploration of the prognostic mechanism of LCNEC is of great significance to its classification, treatment and prognosis.

Background

The roles of cancer stem cells (CSCs) and epithelial-mesenchymal transition (EMT) in solid tumors are well established. However, the interaction between CSCs and EMT in pulmonary large cell neuroendocrine carcinoma (LCNEC) remains unknown. The aim of this study was to investigate the expression and clinical significance of a CSC marker (ALDH1A1) and its correlation with Epithelial-like phenotype marker (E-cadherin) and Mesenchymal-like phenotype marker (N-cadherin) in LCNEC patients.

Methods

Immunohistochemistry (IHC) for ALDH1A1, E-cadherin and N-cadherin expression was conducted on tissue microarrays made from 79 resected LCNEC patient samples. ALDH1A1 protein expression was evaluated by the IHC score, and its correlations with the expression of E-cadherin, N-cadherin and clinicopathological features were determined based on IHC data. Survival analyses were also performed.

Results

ALDH1A1 was positively expressed in 75.9% (60/79 cases) of LCNEC patients. No significant difference in clinicopathological variables was observed between the ALDH1A1-negative and ALDH1A1-positive groups. However, ALDH1A1 expression was positively correlated with E-cadherin (Spearman's rho = 0.229, p-value = 0.007), which represents the epithelial-like phenotype, but not with N-cadherin. Patients with expression of ALDH1A1 had significantly longer disease-free survival (DFS) and overall survival (OS) than those who were ALDH1A1 negative (median DFS: 52 vs 12 months, p = 0.028; median OS: not reached; p = 0.027). Multivariate analysis showed that ALDH1A1 was an independent favorable prognostic factor for DFS (p = 0.032, HR: 0.438, 95% CI: 0.206–0.932) and OS (p = 0.025, HR: 0.279, 95% CI: 0.091–0.852) in LCNEC patients.

Conclusion

This study suggests that ALDH1A1 can act as a favorable independent prognostic factor for LCNEC, which related to the epithelioid phenotype in EMT, and its internal mechanism needs further study.

Management of oral leukoplakia in patients with Fanconi anemia

Fanconi anemia (FA) is a rare genetic disease involving an increased risk of developing acute myeloid leukemia and solid tumors, especially head-and-neck squamous cell carcinomas, for which the oral cavity is the most frequent site of occurrence. The patient presented in this study underwent allogeneic hematopoietic stem cell transplantation (HSCT) and developed nonhomogeneous oral leukoplakia after 7 years, which was promptly removed and diagnosed with high-grade epithelial dysplasia. Many risk conditions for oral squamous cell carcinoma were featured in the present case including FA, allogeneic HSCT, graft-versus-host disease, immunosuppressive therapy, female gender, nonsmoker, tongue location and nonhomogeneous type of leukoplakia. Close follow-up of the entire upper aerodigestive tract mucosa and early removal of all suspected lesions are highly recommended in the management of such patients.

Understanding the complex pathogenesis of oral cancer: A comprehensive review

The pathogenesis of oral cancer is a complex and multifactorial process that requires a deep understanding of the underlying mechanisms involved in the development and progress of malignancy. The ever-improving comprehension of the diverse molecular characteristics of cancer, the genetic and epigenetic alterations of tumor cells, and the complex signaling pathways that are activated and frequently cross talk open up promising horizons for the discovery and application of diagnostic molecular markers and set the basis for an era of individualized management of the molecular defects underlying and governing oral premalignancy and cancer. The purpose of this article is to review the key molecular concepts that are implicated in oral carcinogenesis, especially focusing on oral squamous cell carcinoma, and to review selected biomarkers that play a substantial role in controlling the so-called "hallmarks of cancer," with special reference to recent advances that shed light on their deregulation during the different steps of oral cancer development and progression.

Oral Proliferative Verrucous Leukoplakia: Progression to Malignancy and Clinical Implications. Systematic Review and Meta-Analysis

Simple Summary

Proliferative verrucous leukoplakia (PVL) was recognized in 2005 by the World Health Organization as a rare subtype of true oral leukoplakia, with unknown etiology. Since its first description in 1985, several diagnostic criteria have been proposed over the years. The aim of this systematic review is to investigate the percentage of patients diagnosed with proliferative verrucous leukoplakia who progressed to oral verrucous carcinoma (OVC) or conventional oral squamous cell carcinoma (OSCC).

Abstract

Aim: The aim of the present systematic review was to investigate the risk of malignant transformation of proliferative verrucous leukoplakia (PVL). Materials and Methods: the search was carried out using a combination of terms (leukoplakia OR leucoplakia) AND (multifocal OR proliferative) on the following databases: PubMed, Scopus, Web of Science (WOS Core Collection), Cochrane Library, selecting only articles published since 1985 and in the English language. Demographic, disease-related, and follow-up data extracted from the studies included in the qualitative synthesis were combined. Weighted means ± standard deviations were calculated for continuous variables, while categorical variables were reported as frequencies and percentages. Dichotomous outcomes were expressed as odd ratios (ORs) with 95% confidence intervals (CIs). Odd ratios for individual studies were combined using a random-effects meta-analysis, conducted using Review Manager 5.4 Software (Cochrane Community, Oxford, England). Results: twenty-two articles were included, with a total of 699 PVL patients, undergoing a mean follow-up of 7.2 years. Sixty-six percent of patients were females, with a mean age of 70.2 years, and 33.3% were males, with a mean age of 59.6 years. Most patients were non-smokers and non-alcohol users, and the gingiva/alveolar ridge mucosa was the most involved anatomical site by both PVL appearance and malignant transformation. A total of 320 PVL patients developed oral verrucous carcinoma (OVC) or conventional oral squamous cell carcinoma (OSCC) because of malignant transformation of PVL lesions (45.8%). A statistically significant 3.8-fold higher risk of progression to conventional OSCC was found compared to OVC in PVL patients, with women being 1.7 times more likely to develop oral cancer than men, as a consequence of PVL progression. Moreover, a statistically significant higher likelihood of developing conventional OSCC in female PVL patients than in males was found. In 46.5% of patients with PVL malignant transformation, multiple carcinomas, in different oral sites, occurred during follow-up. Conclusions: PVL is an aggressive lesion, which, in a high percentage of cases (almost 50%), undergoes malignant transformation, mainly toward OSCC. The female gender is most affected, especially in the elderly, with a negative history for alcohol and tobacco consumption.

Oral Cancer: Genetics and the Role of Precision Medicine

Oral squamous cell carcinoma (OSCC) is one of the leading cancers in the world. OSCC patients are managed with surgery and/or chemoradiation. Prognoses and survival rates are dismal, however, and have not improved for more than 20 years. Recently, the concept of precision medicine was introduced, and the introduction of targeted therapeutics demonstrated promising outcomes. This article reviews the current understanding of initiation, progression, and metastasis of OSCC from both genetic and epigenetic perspectives. In addition, the applications and integration of omics technologies in biomarker discovery and drug development for treating OSCC are reviewed.

The role of NBI with flexible video-endoscope in the follow-up of head and neck cancer patients: a prospective study

PURPOSE

Narrow band imaging (NBI) enhances mucosal vasculature and could help in the identification of recurrences. We assessed the effectiveness of NBI with flexible video-endoscope in the early detection of recurrence after treatment of head and neck squamous cell carcinoma, its diagnostic advantage over high-definition white-light (HD WL) endoscopy, also in relation to recurrence site, and the influence of previous radiotherapy (RT) or chemotherapy (CT). Moreover, we investigated the association between index tumor site and the risk of developing recurrence, and the relation between index tumor site and recurrence site.

METHODS

From January 2018 to November 2020, 160 patients previously treated with surgery and/or RT ± CT were evaluated using NBI with flexible video-endoscope. Sensitivity, specificity, positive/negative predictive value, and accuracy were calculated for NBI and HD WL, and compared using the McNemar test. The Fisher exact test was used to compare the other associations investigated.

RESULTS

The difference between NBI and HD WL sensitivity was statistically significant (p < 0.001). The NBI diagnostic advantage was 62.5%, highest in the hypopharynx (p = 0.05), and was not influenced by previous RT or CT (p = 0.49). Index tumor site statistically related with recurrence site (p < 0.001), but not with the risk of developing recurrence (p = 0.81).

CONCLUSION

NBI with flexible video-endoscope could represent a valid option to detect recurrence early during the follow-up, especially in a difficult-to-visualize site such as the hypopharynx.

Cancer Stem Cells in Head and Neck Squamous Cell Carcinoma-Treatment Modalities

Head and neck squamous cell carcinoma (HNSCC) belongs to the most frequent cancer subtypes in the world. Mutations due to genetic and chromosomal instability, syndromes such as Fanconi anemia and the Bloom syndrome, environmental risk factors such as tobacco smoking, alcohol and human papillomavirus infection (HPV) subtypes 16,18,31,33,35,52,58 are implicated in its pathogenesis. The HNSCC belongs to the solid tumors of epithelial origin and consists of stromal, inflammatory, cancer cells and most importantly a fraction of them, the cancer stem cells (CSCs). The identification of the CSCs through their biomarkers such as CD44, CD10, CD166, CD133, CD271, ALDH, Oct4, Nanog, Sox2 and Bmi1, the maintenance of their subpopulation through epithelial to mesenchymal transition, the role of HPV infection regarding their prognosis and of their microenvironment regarding their resistance to therapy, all constitute key elements that must be taken thoroughly into consideration in order to develop an effective targeted therapy. There are already therapies in place targeting specific related biomarkers, important biochemical pathways and growth factors. The aim of this literature review is to illustrate the treatment modalities available against the cancer stem cells of head and neck squamous cell carcinoma.

Precision Medicine Gains Momentum: Novel 3D Models and Stem Cell-Based Approaches in Head and Neck Cancer

Despite the current progress in the development of new concepts of precision medicine for head and neck squamous cell carcinoma (HNSCC), in particular targeted therapies and immune checkpoint inhibition (CPI), overall survival rates have not improved during the last decades. This is, on the one hand, caused by the fact that a significant number of patients presents with late stage disease at the time of diagnosis, on the other hand HNSCC frequently develop therapeutic resistance. Distinct intratumoral and intertumoral heterogeneity is one of the strongest features in HNSCC and has hindered both the identification of specific biomarkers and the establishment of targeted therapies for this disease so far. To date, there is a paucity of reliable preclinical models, particularly those that can predict responses to immune CPI, as these models require an intact tumor microenvironment (TME). The "ideal" preclinical cancer model is supposed to take both the TME as well as tumor heterogeneity into account. Although HNSCC patients are frequently studied in clinical trials, there is a lack of reliable prognostic biomarkers allowing a better stratification of individuals who might benefit from new concepts of targeted or immunotherapeutic strategies. Emerging evidence indicates that cancer stem cells (CSCs) are highly tumorigenic. Through the process of stemness, epithelial cells acquire an invasive phenotype contributing to metastasis and recurrence. Specific markers for CSC such as CD133 and CD44 expression and ALDH activity help to identify CSC in HNSCC. For the majority of patients, allocation of treatment regimens is simply based on histological diagnosis and on tumor location and disease staging (clinical risk assessments) rather than on specific or individual tumor biology. Hence there is an urgent need for tools to stratify HNSCC patients and pave the way for personalized therapeutic options. This work reviews the current literature on novel approaches in implementing three-dimensional (3D) HNSCC in vitro and in vivo tumor models in the clinical daily routine. Stem-cell based assays will be particularly discussed. Those models are highly anticipated to serve as a preclinical prediction platform for the evaluation of stable biomarkers and for therapeutic efficacy testing.

Targeting the genetic landscape of oral potentially malignant disorders has the potential as a preventative strategy in oral cancer

This study reviews the molecular landscape of oral potentially malignant disorders (OPMD). We examine the impact of tumour heterogeneity, the spectrum of driver mutations (TP53, CDKN2A, TERT, NOTCH1, AJUBA, PIK3CA, CASP8) and gene transcription on tumour progression. We comment on how some of these mutations impact cellular senescence, field cancerization and cancer stem cells. We propose that OPMD can be monitored more closely and more dynamically through the use of liquid biopsies using an appropriate biomarker of transformation. We describe new gene interactions through the use of a systems biology approach and we highlight some of the first studies to identify functional genes using CRISPR-Cas9 technology. We believe that this information has translational implications for the use of re-purposed existing drugs and/or new drug development. Further, we argue that the use of digital technology encompassing clinical and laboratory-based data will create relevant datasets for machine learning/artificial intelligence. We believe that therapeutic intervention at an early molecular premalignant stage should be an important preventative strategy to inhibit the development of oral squamous cell carcinoma and that this approach is applicable to other aerodigestive tract cancers.

Resection Margins in Head and Neck Cancer Surgery: An Update of Residual Disease and Field Cancerization

Surgery is one of the mainstays of head and neck cancer treatment, and aims at radical resection of the tumor with 1 cm tumor-free margins to obtain locoregional control. Surgical margins are evaluated by histopathological examination of the resection specimen. It has been long an enigma that approximately 10-30% of surgically treated head and neck cancer patients develop locoregional recurrences even though the resection margins were microscopically tumor-free. However, the origins of these recurrences have been elucidated by a variety of molecular studies. Recurrences arise either from minimal residual disease, cancer cells in the surgical margins that escape detection by the pathologist when examining the specimen, or from precancerous mucosal changes that may remain unnoticed. Head and neck tumors develop in mucosal precursor changes that are sometimes visible but mostly not, fueling research into imaging modalities such as autofluorescence, to improve visualization. Mostly unnoticed, these precancerous changes may stay behind when the tumor is resected, and subsequent malignant progression will cause a local relapse. This led to a clinical trial of autofluorescence-guided surgery, of which the results were reported in 2020. This review focuses on the most recent literature of the improved diagnosis of the resection margins of surgically treated head and neck cancer patients, the pathobiological origin of recurrent disease, and relevant biomarkers to predict local relapse. Directions for further research will be discussed, including potential options for improved and personalized treatment, based on the most recently published data.

Second primary tumors in head and neck cancer patients: The importance of a "tailored" surveillance

OBJECTIVE

Head and neck cancer survivors have increased risk of developing second primary tumors compared to overall population. Because second primary represents a major cause of morbidity and mortality in this population, early detection is fundamental.

MATERIALS AND METHODS

In this 10-year single-institution study, we investigated the following: incidence, clinical-pathological risk factors, and survival of patients with second primary tumor. We included all patients with diagnosis of squamous cell carcinoma of the head and neck seen at the Modena University Hospital from 2008 to 2018.

RESULTS

Among 1,177 patients included, 222 (18.9%) developed second primary tumor; its survival probability at 5 years was 40.6%. Alcohol consumption (p = .0055) and index cancer in oropharynx (p = .0029), supraglottic larynx (p = .0000), glottic larynx (p = .0222) were associated with higher risk of second primary. The most common second primary sites were head and neck district and lung (70, 31.5%, and 67, 30.2%, respectively). Head and neck district were more common in oral cavity (18, 43%) and oropharynx index cancer (20, 31%); lung second primary in hypopharynx (4, 40%), supraglottic larynx (17, 43%), and glottic larynx index cancer (23, 35%).

CONCLUSION

Head and neck cancer survivors developing a second primary tumor have dismal prognosis. Tailored surveillance is recommended.

Breast tumour cell subpopulations with expression of the MYC and OCT4 proteins

The MYC and OCT4 genes are known factors associated with maintaining pluripotency and are linked with a more aggressive course, progression, and resistance to therapy in cancer. Determining the subpopulations of tumour cells expressing the Myc and Oct4 proteins will provide an opportunity to understand which tumour cell subpopulations expressing MYC and OCT4 are associated with metastasis and resistance and which subpopulations can be targeted by anti-MYC and anti-OCT4 therapy. The study included paraffin-embedded tissue from tumours from 27 patients with luminal B breast cancer obtained after neoadjuvant chemotherapy (NACT). Immunofluorescence staining was used to identify subpopulations of tumour cells expressing Myc, Oct4 and Snai2 (Opal™ 7-Color Kit (PerkinElmer, Hopkinton, MA). The following tumour cell subpopulations were identified with the Myc and Oct4 proteins and the Snai2 EMT marker: stem/progenitor tumour cells with/without Myc, Oct4 or Snai2 expression; differentiated tumour cells with/without Myc, Oct4 or Snai2 expression; and other nontumour cells (CK7^-EpCAM^-CD44^+/-Myc^+/-(Oct4, Snai2)^+/-) within the inflammatory infiltrate in the tumour parenchyma and stroma. The circulating tumour cell subpopulations with Oct4 protein expression in the bloodstream were studied by flow cytometry. It was found that in patients with partial regression (PR) in response to NACT, the frequency of tumour stem cells was 3.6-fold increased (p = 0.038) in the non-EMT state (CK7⁺EpCam⁺CD44⁺Snai2^-). In patients with metastases, there was a statistically significant 2.5-fold increase in the frequency of differentiated tumour cells with Myc expression (CK7⁺EpCam⁺CD44^-Myc⁺) and a 2.7-fold increase in the frequency of cells with Oct4 expression (CK7⁺EpCam⁺CD44^-OCT4⁺). In the next stage, the frequencies of subpopulations with expression of the Oct4 protein and signs of EMT among circulating tumour cells (CTCs) were determined. In patients with metastases, the frequency of tumour stem cells in the EMT state (CD326⁺CD44⁺CD24^-CD325⁺) (p = 0.015) was more than fourfold increased, and the frequency of progenitor tumour cells with expression of the Oct4 stem protein (CD326⁺CD44⁺CD24⁺Oct4⁺) (p = 0.016) was almost sixfold higher than that in patients without metastases. Nonstem (differentiated) tumour cells with expression of the stemness proteins Myc and Oct4 were present in the breast tumour. Their content was significantly higher in residual tumours after NACT in patients who subsequently developed metastases compared with that in patients without metastases. Such cells are a new in situ marker of metastasis.

Expression of PD-L1, cancer stem cell and epithelial-mesenchymal transition phenotype in non-small cell lung cancer

The purpose of this study was to investigate the expression of PD-L1, cancer stem cells (CSC) markers (CD44, NANOG, and ALDH1) and epithelial-mesenchymal transition (EMT) markers and to evaluate their correlation and prognostic significance in non-small cell lung cancer (NSCLC) patients. PD-L1 protein expression was evaluated in resected 277 NSCLC cases and its correlation with CSC and EMT marker expression and survival was determined based on immunohistochemical (IHC) analysis. mRNA expression obtained from The Cancer Genome Atlas and the Kaplan-Meier plotter database were compared with the IHC results. PD-L1 expression was negatively correlated with ALDH1 expression in adenocarcinoma by IHC and mRNA expression. PD-L1 expression was also associated with mesenchymal phenotype (vimentin and TWIST) adenocarcinoma by IHC and mRNA expression. PD-L1 expression was associated with poor prognosis in adenocarcinoma by IHC. However, NANOG or ALDH1 expression measured by IHC and mRNA expression was correlated with a favourable prognosis in adenocarcinoma. Epithelial marker p120-catenin detected by IHC and mRNA expression was associated with a favourable prognosis in adenocarcinoma, however mesenchymal marker TWIST was associated with a worse prognosis. Patients with low PD-L1 and high ALDH1 expression showed more favourable prognoses than adenocarcinoma patients with other expression patterns. In multivariate analysis, ALDH1 detected by IHC and mRNA expression was an independent favourable prognostic marker for adenocarcinoma. Our study results support the hypothesis that PD-L1 interacts with CSC and EMT features and that PD-L1, ALDH1, and the mesenchymal phenotype may serve as tandem markers as prognostic factor in NSCLC.

The differences of immunologic and TP53 mutant phenotypes between synchronous and metachronous head and neck cancer and esophageal cancer

OBJECTIVE

To determine the tumor genomic, immunologic expression, and risk factors of treatment outcomes for patients with double head and neck squamous cell carcinoma (HNSCC) and esophageal squamous cell carcinoma (ESCC).

METHODS

We reviewed patients with double HNSCC and ESCC between 1995 and 2014. The TP53 genomic mutation, CD8+ tumor infiltrating lymphocytes (TIL) and tumor programmed cell death ligand 1 (PD-L1) expression of paired HNSCC and ESCC were analyzed.

RESULTS

A total of 116 patients (57 metachronous and 59 synchronous) were included. There were 88 (75.86%) patients with HNSCC and 80 (68.97%) with ESCC harboured TP53 disruptive mutation. Nearly 106 (91.38%) patients had different clonality of TP53 mutation in paired HNSCC and ESCC. The immunologic expression of synchronous and metachronous patients was significantly different. Compared to the metachronous patients, the synchronous patients had significantly higher HNSCC CD8+ TIL (p = 0.03), ESCC CD8+ TIL (p < 0.001), HNSCC PD-L1+ tumor proportion score (TPS, p = 0.04), and ESCC PD-L1+ TPS (p = 0.04). Furthermore, among the synchronous patients, the immunologic expression between HNSCC and ESCC was significantly correlated. The CD8+ TIL and PD-L1 TPS had strongly (r = 0.63, p < 0.0001) and moderately (r = 0.42, p = 0.001) positive correlations, respectively. Finally, advanced stage (III/IV) HNSCC was a significant factor for disease-free (p = 0.03) and overall survival (p = 0.005).

CONCLUSION

In patients with double HNSCC and ESCC, nearly all HNSCC and ESCC were of multicentric origin. For the synchronous patients, there was more adaptive immune resistance in HNSCC and ESCC. The immunologic expression between paired HNSCC and ESCC was also significantly correlated.

Cancer stem cells and field cancerization of head and neck cancer - An update

Oral cancer results due to multiple genetic alterations that transform the normal cells in the oral cavity into neoplastic cells. These genetic changes in a particular tumor field lead to a rapid expansion of preneoplastic daughter cells producing malignant phenotype but the malignancy results due to such genetic changes occurr over several years. The morphological changes in these transformed cells help in the diagnosis of malignancy. Thus, the early changes at the gene level are present in the population of daughter cells in the organ, which explains the concept of field cancerization. Cancer stem cells (CSCs) represent a group of cells that have the capacity of self-renewal and have the potential to differentiate into other types of tumor cells. This review explains the cellular and genetic basis of field cancerization and the role of cancer stem cells in field cancerization.

Do betel quid and areca nut chewing deteriorate prognosis of oral cancer? A systematic review, meta-analysis, and research agenda

OBJECTIVE

To explore the correlations between the habit of betel quid and areca nut (BQ-AN) chewing and the prognosis of oral cancer (OC).

METHODS

We performed a systematic review and meta-analysis to clarify this issue. Data searches were performed using PubMed, Web of Science, Epistemonikos, and Embase databases through November 2019. The primary outcome was the difference in the prognosis of OC between BQ-AN chewers and non-chewers, measured in terms of 5-year overall survival (OS) and 5-year disease-specific survival (DSS) log (HR) reported in articles. The pooled HR with 95% CI of 5-year OS and 5-year DSS was calculated using a fixed-effects model.

RESULTS

Ten articles with eleven OS or DSS survival studies (one of the articles contained two studies), which were published between 2003 and 2017, were eligible for inclusion in the present study. All the 11 studies were observational studies, among which 10 were retrospective and 1 was prospective. One study measured both OS and DSS. Eight studies, with a total of 2,761 patients, used 5-year OS as the primary endpoint and four studies, with a total of 2,551 patients, used 5-year DSS. Overall, the pooled HR evaluating BQ-AN chewers was 1.26 (95% CI: 1.09-1.46) for 5-year OS and 1.40 (95% CI: 1.15-1.70) for 5-year DSS, compared with non-chewers. There was a significant association between BQ-AN chewing and OC survival.

CONCLUSIONS

Betel quid and areca nut chewing is significantly associated with poor prognosis in patients with OC.

Amplifications of stemness genes and the capacity of breast tumors for metastasis

INTRODUCTION

The phenomenon of non-CSC (cancer stem cell) to CSC plasticity has been previously described in multiple studies and occurs during the ectopic expression of stemness genes such as OCT3, SOX2, KLF4, MYC, NOTCH1, and NANOG. In our opinion, acquiring the ability to ectopically express stemness genes, selected by bioinformatics analysis and, accordingly, non-CSC to CSC plasticity, is due to amplification of genes at the following locations: 3q, 5p, 6p, 7q, 8q, 13q, 9p, 9q, 10p, 10q21.1, 16p, 18chr, 19p. This paper demonstrates the significance of stemness gene amplifications leading to metastasis and stem-like cancer cell activity.

MATERIALS AND METHODS

In our studies, stemness gene amplifications were determined using the CytoScan HD Array. We studied the association of changes in stemness gene amplifications in tumors with metastasis treated with neoadjuvant chemotherapy (NAC) in 50 patients with breast cancer. We used qPCR to evaluate the expression of 13 stemness genes in tumors before and after NAC in 98 patients with breast cancer. Using primary cultures from the breast tumor of patient St23784/17 with stemness gene amplifications (SOX2, MYC, KLF4, NOTCH1, NODAL) and patient Ti41749/17 without stemness gene amplifications in the tumor, we studied the expression of stemness genes, proliferative tumor stem-cell activity, mammosphere formation, and expression of the CD44 tumor stem cell marker.

RESULTS

The occurrence of amplifications at regions of stemness gene localization during NAC (22% cases) in residual tumors was associated with a very high metastasis rate (91% cases). Eliminating tumor clones with stemness gene amplifications using NAC (42% cases) led to 100% metastasis-free survival. In patients who developed hematogenic metastases after treatment, the expression of 7/13 stemness genes in the residual tumor after NAC was statistically higher than in patients without metastases. Primary cultures of EpCam⁺ tumor cells from patients with stemness gene amplifications revealed high proliferative activity. After the 3rd passage, the number of tumor cells increased 30-fold. Due to IL-6, this cell population showed a 2.5-fold increase in the EpCam⁺CD44^hiCD24^-/low and 2-fold decrease in the EpCam⁺CD44^lowCD24^- subpopulations of tumor stem cells; the formation of mammospheres was also observed. Primary cultures of EpCam+ tumor cells from the patient with no stemness gene amplifications had relatively low proliferative activity. IL-6 caused a 2.3-fold increase in the EpCam⁺CD44^lowCD24^- and 2-fold decrease in the EpCam⁺CD44^hiCD24^-/low subpopulations of tumor stem cells with no induction of mammospheres.

CONCLUSIONS

The results of this study show that stemness gene amplifications in tumor cells are associated with metastasis and determine their potential stem property activation and non-CSC to CSC plasticity with the formation of EpCam⁺CD44^hiCD24^-/low cells, active proliferation, mammosphere formation, and metastasis.

Risk of second primary cancer in oral squamous cell carcinoma

BACKGROUND

The incidence and survival of oral squamous cell carcinoma (OSCC) patients have increased in recent years. Understanding their long-term survival aspects is essential for optimal treatment and follow-up planning. Almost one in five cancers diagnosed occurs nowadays in individuals with a previous diagnosis of cancer.

METHODS

Patients diagnosed with primary OSCC during 1953-2015 were retrieved from the Finnish Cancer Registry. Both standardized incidence ratios (SIR) and excess absolute risk (EAR) per 1000 person-years at risk (PYR) of second primary cancer (SPC) were calculated relative to the general population.

RESULTS

Among 6602 first primary OSCC patients there were 640 (10%) SPCs. The SIR for SPCs was 1.85 (95% CI: 1.71-1.99, P < .001) corresponding to an EAR of 8.78 (95% CI: 7.29-10.26).

CONCLUSIONS

Health care professionals should be aware of the second primary cancer risk after management of primary OSCC and patients need to be counseled about this phenomenon.

Fenretinide, Tocilizumab, and Reparixin Provide Multifaceted Disruption of Oral Squamous Cell Carcinoma Stem Cell Properties: Implications for Tertiary Chemoprevention

Locoregional recurrence of oral squamous cell carcinoma (OSCC) dramatically reduces patient survival. Further, as many OSCC recurrences are inoperable, radiotherapy and chemotherapy with or without biological adjuncts are the remaining treatment options. Although the tumors may initially respond, radiotherapy- and chemotherapy-resistant cancer stem cells (CSC) can readily repopulate OSCC tumors. Currently, following the initial OSCC treatment, patients are closely monitored until a recurrence or a second primary is detected. Identification of agents with complementary mechanisms to suppress CSC tumorigenic functions could change this passive approach. The goals of this study were twofold: (1) develop and validate CSC-enriched (CSCE) OSCC cell lines and (2) identify chemopreventive agents that obstruct multiple CSCE protumorigenic pathways. CSCE cultures, which were created by paclitaxel treatment followed by three tumorsphere passes, demonstrated CSC characteristics, including increased expression of stem cell and inflammatory genes, increased aldehyde dehydrogenase (ALDH) activity, and enhanced in vitro/in vivo proliferation and invasion. Three chemopreventives, fenretinide, tocilizumab, and reparixin, were selected due to their distinct and complementary CSC-disruptive mechanisms. The CSCE selection process modulated the cells' intermediate filaments resulting in an epithelial-predominant (enhanced cytokeratin, proliferation, IL6 release) line and a mesenchymal-predominant (upregulated vimentin, invasive, IL8 release) line. Our results confirm that 4HPR binds with appreciably higher affinity than Wnt at the Frizzled binding site and significantly inhibits CSC-enabling Wnt-β-catenin downstream signaling. Notably, combination fenretinide-tocilizumab-reparixin treatment significantly suppressed IL6 and IL8 release, stem cell gene expression, and invasion in these diverse CSCE populations. These promising multiagent in vitro data provide the basis for our upcoming in vivo CSCE tertiary chemoprevention studies.

Susceptibility of Multiple Primary Cancers in Patients With Head and Neck Cancer: Nature or Nurture?

Multiple primary cancers (MPCs) are major obstacles to long-term survival in head and neck cancer (HNSCC), however, the molecular mechanism underlying multiple carcinogenesis remains unclear. “Field cancerization” is a classical theory to elaborate the malignant progression of MPCs. Apart from environmental and immune factors, genetic factors may have great potential as molecular markers for MPCs risk prediction. This review focuses on inherited and acquired gene mutations in MPCs, including germ-line mutation, single-nucleotide polymorphism, chromosomal instability, microsatellite instability and DNA methylation. And definition and prognosis of MPCs have also been discussed. These may pave the way for the early detection, prevention and effective treatment of MPCs in HNSCC.

Cancer stem cell markers ALDH1 and Bmi1 expression in oral erythroplakia revisited: Implication for driving the process of field cancerization

The correlation of ALDH1 and Bmi1 expression in potentially malignant oral erythroplakia (OE) with oral carcinoma development was reported in our earlier study. Interestingly, a model of field cancerization orchestrated by the cancer stem cells (CSC) was proposed and suggested the identification of CSC-specific markers is useful for prognosis and providing novel targets for prevention and treatment of field cancerization. We revisited the correlation of ALDH1 and Bmi1 expression in OE with the second and multiple carcinomas development. Strikingly, we observed that the expression of ALDH1 and Bmi1 within a single potentially malignant OE lesion significantly correlate with subsequently developing multiple and multifocal carcinomas, which parallels the process of oral field cancerization. Significantly, ALDH1 and Bmi1 are well-defined markers of CSC for head and neck cancer. Consequently, we provided a preliminary evidence for CSC driving the process of field cancerization.

Second primary tumors in proliferative verrucous leukoplakia: a series of 33 cases

OBJECTIVES

To describe the number of second primary malignancies in a series of 33 patients with proliferative verrucous leukoplakia (PVL), detailing the mean time between primary malignancies and their clinical characteristics.

MATERIALS AND METHODS

Two groups of patients were included in this study: group 1 comprised 33 PVL patients who had developed ≥ 2 oral squamous cell carcinoma (OSCC) and group 2 comprised 48 PVL patients without malignant degeneration. We compared the groups with regard to age, gender, oral location, and number of oral sites affected. For patients in group 1, we determined the locations, clinical forms, and TNM stages of oral cancers. We also recorded the intervals of time between instances of oral cancer for all patients.

RESULTS

The groups did not differ significantly in age; however, group 1 included more women (p < 0.05). The follow-up period and number of oral PVL locations were greater in group 1 (p < 0.01). Moreover, in group 1, as the number of OSCCs increased, the intervals between them became shorter. The gingiva was the most common site. The mean number of cancers in group 1 was 3.15; five second primary tumors were diagnosed in one patient.

CONCLUSIONS

Multiple cancers in PVL patients were more frequently located on the gingiva in the form of erythroleukoplastic areas. In addition, the interval between new cancers decreased over time.

CLINICAL RELEVANCE

This is the series with the highest number of cases described with second primary tumors in PVL.

Impact of dysplastic surgical margins for patients with oral squamous cell carcinoma

OBJECTIVES

Dysplastic changes at the surgical margin of oral squamous cell carcinoma (OSCC) could be encountered frequently. However, the impact of a dysplastic surgical margin on patients with OSCC remains unclear.

MATERIALS AND METHODS

Retrospectively, we reviewed patients with OSCC who were diagnosed and treated at the National Taiwan University Hospital between January 2010 and December 2015. Patients were divided into four groups: clear (≥5 mm), close (<5 mm), positive, and dysplastic margins.

RESULTS

Of 1642 patients, 596 had clear margin, 169 had positive margin, 707 had close margin, and 170 had dysplastic margin. The mean age at diagnosis was 55 ± 11 years (range, 16-97 years). Dysplastic margins were frequently present in patients with primary T1/T2 OSCC (odds ratio [OR] = 1.7, p = 0.009), tumor without perineural invasion (OR = 1.48, p = 0.04), and tumor thickness ≤10 mm (OR = 1.94, p = 0.001). In patients with clear, close, positive, and dysplastic margins, the 5-year disease-free survival rates were 63.1%, 51%, 37.2%, and 54.7%, respectively; overall survival (OS) rates were 71.1%, 61.9%, 49%, and 72%, respectively. Disease-free and overall survival were not significantly different in patients with dysplastic and clear margins (p = 0.37 and p = 0.38, respectively). Adjuvant radiotherapy had no significant benefit for patients with dysplastic margins. Finally, a multivariate analysis showed that the presence of a dysplastic margin was not an independent risk factor for disease-free (p = 0.43) and overall survival (p = 0.71).

CONCLUSIONS

The survival rates of the patients with OSCC who had dysplastic margin were significantly better than those with positive margin.

Podoplanin and ABCG2 expression in oral erythroplakia revisited: Potential evidence for cancer stem cells driving the process of field cancerization

A model of field cancerization orchestrated by the cancer stem cells (CSC) was proposed. Podoplanin and ABCG2 are promising marker of CSCs for head and neck cancer. We revisited the correlation of the two markers with the follow-up data of the patients with oral erythroplakia (OE). Strikingly, we observed that the expression of podoplanin and ABCG2 within a single pre-neoplastic OE lesion significantly correlate with subsequently developing multiple and multifocal carcinomas, thus to some extent demonstrating the concept of field cancerization. Collectively, a point to highlight was that a preliminary evidence that provided by this revisited study supported the perspective on cancer stem cells driving the process of field cancerization.

Lactate Promotes Cancer Stem-like Property of Oral Sequamous Cell Carcinoma

Accumulation of lactate in tumor has been linked to poor prognosis of oral squamous cell carcinoma (OSCC), but the underlying mechanism remained largely uncertain. Previous studies have suggested that presence of cancer stem cells (CSCs) closely correlated with cellular malignancy of OSCC. Here, using 3D organoid culture model, we investigated whether lactate promoted CSCs phenotype in primary OSCC cells. We generated organoids using fresh OSCC specimens and verified that organoids recapitulated histopathology and cellular heterogeneity of parental tumor. Organoids were then transfected with a Wnt reporter to visualize Wnt activity. The sphere forming assay demonstrated that high Wnt activity functionally designated CSCs population in OSCC cells. Further investigations indicated that lactate treatment promoted Wnt activity and increased the expression of CSCs (i.e. CD133⁺ cells) in organoids. Moreover, silencing monocarboxylate transporter 1 (MCT1), the prominent path for lactate uptake in human tumor with siRNA significantly impaired organoid forming capacity of OSCC cells. Together, our study demonstrated that lactate can promote CSCs phenotype of OSCC, and MCT1 may be a therapeutic target against OSCC growth.

R-spondin 2-LGR4 system regulates growth, migration and invasion, epithelial-mesenchymal transition and stem-like properties of tongue squamous cell carcinoma via Wnt/β-catenin signaling

Background

R-spondins (Rspo) and leucine-rich repeat-containing G-protein-coupled receptors (LGR) play important roles in development, stem cells survival, and tumorigenicity by activating Wnt signaling pathway. Whether R-spondins-LGR signaling affects the progression of squamous cell carcinoma (SCC) remain unknown. This study aims to uncover the role of R-spodin2/LGR4 in tongue SCC (TSCC).

Methods

The expression of Rspo2 in TSCC specimens and its correlation with TSCC clinical outcome were evaluated. Levels of Rspo2 or LGR4 were altered by pharmacological and genetic approaches, and the effects on TSCC progression were assessed.

Findings

Aberrantly high levels of Rspo2 were detected in TSCC specimens. Its levels were closely related with lymph node metastasis, clinical stage and survival rate in patients with tongue SCC. Exogenous Rspo2 or overexpression of Rspo2 promoted growth, migration and invasion, epithelial-mesenchymal transition (EMT) and stem-like properties in SCC both in vivo and in vitro. Silence of Rspo2 abolished these phenotypes. LGR4 was functionally upregulated by Rspo2 in TSCC. Overexpression of Rspo2 increased, whereas Rspo2 silencing decreased the expression of LGR4, leading to subsequent phosphorylation of LRP6 and nuclear translocation of β-catenin in TSCC cell lines. This nuclear translocation of β-catenin was associated with a significant alteration in TCF-1, a downstream nuclear transcription factor of β-catenin, as well as its target genes: CD44, CyclinD1 and c-Myc.

Interpretation

Rspo2-LGR4 system regulates growth, migration and invasion, EMT and stem-like properties of TSCC via Wnt/β-catenin signaling pathway.

•

Rspo2 and LGR4 are aberrantly expressed in TSCC.

•

Rspo2-LGR4 up-regulates growth, migration and invasion, EMT and stem-like properties of TSCC.

•

Rspo2-LGR4 regulates TSCC progression via Wnt/β-catenin pathway.

A History of Innovations in the Diagnosis and Treatment of Oral and Head and Neck Cancer

Historical records as far back as 3000 BCE show that oral and head and neck cancer was a disease process well known to Egyptian physicians. Luminaries such as Hippocrates, Galen, Pott, and Virchow were instrumental in shaping our understanding of the etiology and pathogenesis of cancer. During the 20th century, evidence-based medicine catalyzed the development of rigorous science-based diagnostic and treatment protocols. The use of surgery, therapeutic radiation, and chemotherapy as single-treatment agents or in combination with one another gradually emerged as the preferred approach to cancer therapy. The recognition of tobacco, alcohol, and human papillomavirus as etiological agents in oral and head and neck cancer prompted the development of new diagnostic aids and treatment strategies to mitigate cancer progression. More in-depth mechanistic insights into the multistep process of oral and head and neck cancer were made possible by the use of the hamster buccal pouch and mouse models. New technologies, such as the sequencing of the human genome, metabolomics, and proteomics, have provided the foundation for what we today call precision medicine. The future success of tailored medical treatment for cancer patients will depend on the discovery of new druggable targets with improved therapeutic efficacy. As the precision and sensitivity of existing tools for prevention and risk assessment improve, greater accuracy will be achieved in predicting health outcomes.