Immunohistochemical evaluation of mast cells and vascular endothelial proliferation in oral precancerous lesion-leukoplakia

Scanning darkfield high-resolution microendoscope for label-free microvascular imaging

Characterization of microvascular changes during neoplastic progression has the potential to assist in discriminating precancer and early cancer from benign lesions. Here, we introduce a novel high-resolution microendoscope that leverages scanning darkfield reflectance imaging to characterize angiogenesis without exogenous contrast agents. Scanning darkfield imaging is achieved by coupling programmable illumination with a complementary metal-oxide semiconductor (CMOS) camera rolling shutter, eliminating the need for complex optomechanical components and making the system portable, low-cost (<$5,500) and simple to use. Imaging depth is extended by placing a gradient-index (GRIN) lens at the distal end of the imaging fiber to resolve subepithelial microvasculature. We validated the capability of the scanning darkfield microendoscope to visualize microvasculature at different anatomic sites in vivo by imaging the oral cavity of healthy volunteers. Images of cervical specimens resected for suspected neoplasia reveal distinct microvascular patterns in columnar and squamous epithelium with different grades of precancer, indicating the potential of scanning darkfield microendoscopy to aid in efforts to prevent cervical cancer through early diagnosis.

The Immune Cells in the Development of Oral Squamous Cell Carcinoma

A still unresolved issue surrounding tumor formation concerns the role that the immune system plays in preventing the formation and progression of neoplasia, including oral squamous cell carcinoma (OSCC). Antitumor immunity has historically been seen as a critical barrier for cancer cells to develop, grow and spread, and this can be modulated using immunotherapies to achieve antitumor clinical responses. However, it has recently become clear that tumor-associated immunity, particularly the inflammatory microenvironment, has the paradoxical effect of enhancing tumorigenesis and progression. In this review, we discuss the multifaceted function of infiltrating immune cells in suppressing or promoting premalignancy and cancer. In particular, we report on the evidence supporting a role for T lymphocytes, dendritic cells, macrophages, and neutrophils in the development and progression of oral potentially malignant disorders (OPMD) and OSCC. We also draw attention to the clinical relevance of immune cell phenotypes and associated molecules for use as biomarkers and to the translatability of current research findings to improve classification systems and precision medicine in patients with OSCC.

Correlation of Mast Cell and Angiogenesis in Oral Lichen Planus, Dysplasia (Leukoplakia), and Oral Squamous Cell Carcinoma

OBJECTIVE

The aim of this study was to compare and correlate mast cell density (MCD) and microvessel density (MVD) between normal oral mucosa, oral lichen planus, various grades of dysplasia, and oral squamous cell carcinoma (OSCC).

MATERIALS AND METHODS

The study comprised a total of 75 samples, of which 65 were archival tissue blocks of histopathologically confirmed cases, which included 10 cases of oral lichen planus, 25 cases of dysplasia (mild [n=10], moderate [n=10], and severe [n=5]), and 30 cases of OSCC (well differentiated [n=10], moderately differentiated [n=10], and poorly differentiated [n=10]), and 10 samples of normal oral mucosa. All the sections were immunohistochemically stained with anti-CD34 and counterstained with toluidine blue stain. Mean MCD and MVD were determined and analyzed using ANOVA test and compared between the lesions using Tukey HSD test. Pearson's correlation coefficient test was used to correlate these two factors between various lesions.

RESULTS

Mean MCD and mean MVD were found to be increased in all the lesions compared to normal oral mucosa, and the values were statically significant. Overall, MCD and MVD showed a significant positive correlation (r=0.640).

CONCLUSION

Increase of MCD and MVD and their positive correlation in all the lesions have emphasized their role in the pathogenesis and disease progression.

Histomorphometric Comparative Analysis between Oral Dysplastic Potentially Malignant Disorders and Oral Squamous Cell Carcinoma

Objective This study aimed to determine the correlation between the vascular mast cells and inflammatory changes in the potentially malignant disorders, compared to the oral squamous cell carcinoma (OSCC) in varying degrees of dysplasia.

Materials and Methods Thirty samples were selected: 10 of OSCC, 10 of oral leukoplakia, and 10 of actinic keratosis. The toluidine blue technique was used on the mast cells, and hematoxylin and eosin were used for analyzing the lymphocytes, mitosis, and vessels. The quantification was performed using the ImageJ software after obtaining the images by light microscopy with a × 40 objective. Analysis of variance with p < 0.05 was considered for statistical significance.

Results Mast cells ( p < 0.0158), vessels ( p < 0.9431), lymphocytes ( p < 0.0001), and mitoses ( p < 0.0009) were found in OSCC. In potentially malignant disorders, a lower density of these structures and a higher concentration of mitosis in the actinic keratosis were observed.

Conclusion The results showed evidence of a positive correlation between mast cells and vascularization in the OSCC, suggesting the aggression of the disease. Intense inflammatory infiltrate indicates that other molecular events are involved in the carcinogenesis process, and further studies are necessary for a better understanding of it.

Evaluation of Mast Cell Density in the Tumor Microenvironment in Oral Epithelial Dysplasia and Oral Squamous Cell Carcinoma

The objective of this study was to compare mast cell density (MCD) in oral epithelial dysplasias (OED) and oral squamous cell carcinoma (OSCC) and determine its correlation with clinical and histopathologic parameters and the degree of tumor differentiation. Thirty OSCC samples, 14 OED samples, and 4 non-neoplastic oral mucosa samples were analyzed by immunohistochemistry to determine MCD based on the expression of MC tryptase. In addition, MCs were categorized morphologically into degranulated and granulated cells. MCD was significantly higher in OSCC lesions with a greater degree of differentiation (P=0.04). No significant difference in MCD was detected between mild and moderate OED samples (P=0.09). Our findings indicate that MCs are present in the tumor microenvironment and may be associated with a better prognosis.

Mutual concessions and compromises between stromal cells and cancer cells: driving tumor development and drug resistance

BACKGROUND

Various cancers have been found to be associated with heterogeneous and adaptive tumor microenvironments (TMEs) and to be driven by the local TMEs in which they thrive. Cancer heterogeneity plays an important role in tumor cell survival, progression and drug resistance. The diverse cellular components of the TME may include cancer-associated fibroblasts, adipocytes, pericytes, mesenchymal stem cells, endothelial cells, lymphocytes and other immune cells. These components may support tumor development through the secretion of growth factors, evasion from immune checkpoints, metabolic adaptations, modulations of the extracellular matrix, activation of oncogenes and the acquisition of drug resistance. Here, we will address recent advances in our understanding of the molecular mechanisms underlying stromal-tumor cell interactions, with special emphasis on basic and pre-clinical information that may facilitate the design of novel personalized cancer therapies.

CONCLUSIONS

This review presents a holistic view on the translational potential of the interplay between stromal cells and cancer cells. This interplay is currently being employed for the development of promising preclinical and clinical biomarkers, and the design of small molecule inhibitors, antibodies and small RNAs for (combinatorial) cancer treatment options. In addition, nano-carriers, tissue scaffolds and 3-D based matrices are being developed to precisely and safely deliver these compounds.

Distinct Angiogenic Changes during Carcinogenesis Defined by Novel Label-Free Dark-Field Imaging in a Hamster Cheek Pouch Model

There remain gaps in knowledge concerning how vascular morphology evolves during carcinogenesis. In this study, we imaged neovascularization by label-free dark-field microscopy of a 7,12-Dimethylbenz[a]anthracene (DMBA)-induced hamster cheek pouch model of oral squamous cell carcinoma (SCC). Wavelength-dependent imaging revealed distinct vascular features at different imaging depths and vessel sizes. Vascular tortuosity increased significantly in high-risk lesions, whereas diameter decreased significantly in hyperplastic and SCC lesions. Large vessels preserved the same trends seen in the original images, whereas small vessels displayed different trends, with length and diameter increasing during carcinogenesis. On the basis of these data, we developed and validated a classification algorithm incorporating vascular features from different vessel masks. Receiver operator curves generated from the classification results demonstrated high accuracies in discriminating normal and hyperplasia from high-grade lesions (AUC > 0.94). Overall, these results provided automated imaging of vasculature in the earliest stages of carcinogenesis from which one can extract robust endpoints. The optical toolbox described here is simple, low-cost and portable, and can be used in a variety of health care and research settings for cancer prevention and pharmacology research. Cancer Res; 77(24); 7109-19. ©2017 AACR.

Microenvironmental regulation of the progression of oral potentially malignant disorders towards malignancy

Oral potentially malignant disorders (OPMD) develop in a complex tissue microenvironment where they grow sustainably, acquiring oral squamous cell carcinoma (OSCC) characteristics. The malignant tumor depends on interactions with the surrounding microenvironment to achieve loco-regional invasion and distant metastases. Unlike abnormal cells, the multiple cell types in the tissue microenvironment are relatively stable at the genomic level and, thus, become therapeutic targets with lower risk of resistance, decreasing the risk of OPMD acquiring cancer characteristics and carcinoma recurrence. However, deciding how to disrupt the OPMD and OSCC microenvironments is itself a daunting challenge, since their microenvironments present opposite capacities, resulting in diverse consequences. Furthermore, recent studies revealed that tumor-associated immune cells also participate in the process of differentiation from OPMD to OSCC, suggesting that reeducating stromal cells may be a new strategy to prevent OPMD from acquiring OSCC characteristics and to treat OSCC. In this review, we discuss the characteristics of the microenvironment of OPMD and OSCC as well as new therapeutic strategies.

Dark field optical imaging reveals vascular changes in an inducible hamster cheek pouch model during carcinogenesis

In this study, we propose a low-cost cross-polarized dark field microscopy system for in vivo vascular imaging to detect head and neck cancer. A simple-to-use Gabor-filter-based image processing technique was developed to objectively and automatically quantify several important vascular features, including tortuosity, length, diameter and area fraction, from vascular images. Simulations were performed to evaluate the accuracies of vessel segmentation and feature extraction for our algorithm. Sensitivity and specificity for vessel segmentation of the Gabor masks both remained above 80% at all contrast levels when compared to gold-standard masks. Errors for vascular feature extraction were under 5%. Moreover, vascular contrast and vessel diameter were identified to be the two primary factors which affected the segmentation accuracies. After our algorithm was validated, we monitored the blood vessels in an inducible hamster cheek pouch carcinogen model over 17 weeks and quantified vascular features during carcinogenesis. A significant increase in vascular tortuosity and a significant decrease in vessel length were observed during carcinogenesis.

Mast cells and oral pathologies: A Review

Mast cells (MCs) are resident cells of several types of tissues and contain many granules rich in histamine and heparin. They are distributed preferentially about the micro-vascular endothelial cells in the oral mucosa. These cells play a key role in the inflammatory process and thus their number has been found to be altered in various oral pathological conditions such as oral pyogenic granuloma, oral lichen planus, leukoplakia, oral squamous cell carcinoma, periapical cysts etc. The present review article is aimed to describe the alteration in the number of MCs along with their probable roles in these pathological conditions.