Prognostic Nomogram for Lymph-Node Metastasis in Oral Squamous Cell Carcinoma (OSCC) Using Immunohistochemical Marker D2-40.

Introduction: Nomograms are proven in "individualized risk prediction" in sarcomas and breast and prostate cancers. Incorporating immunohistochemical markers and histopathological parameters can enhance accuracy of these graphical representations of statistical predictive models concerning metastasis. D2-40, a monoclonal antibody to podoplanin (regulator of motility expressed in malignant epithelial cells), dually predicts metastatic potential of tumour by estimating the motile tumour phenotype and by detecting lymphatic vessels/density, both essential to metastasis in OSCC. Thus, we propose a model that incorporates D2-40 immunostaining of individual tumour cells (ITC) too with other variables (seen in H+E staining) as a predictive nomogram. Methods: Sixty cases of OSCC were selected with equal number of cases (n=30) of pN0 and pN+ status. Bryne's grading of invasive front of tumour (ITF) was done on H+E-stained slides followed by D2-40 immunostaining for ITCs at ITF and lymphatic vessels. Multivariate regression analysis was used to generate the nomogram of LNM where the predictive contribution of each covariate, namely depth of invasion, D2-40-stained ITCs, gender, histological grade, and worst pattern of invasion (WPOI), was plotted on a scale of 1-100 points. Results: The nomogram showed that the strongest variable in OSCC was the WPOI in H+E-stained section followed by D2-40-positive ITCs and gender. Discussion: Our predictive nomogram for LNM in OSCC surprisingly showed that a tumour with lower score of WPOI (islands vs ITC) showed numerous D2-40-positive ITCs, drastically increasing the probability of metastasis. The concept of "individualized risk prediction" can be used to predict lymph node metastasis using a variety of histopathological criteria that can be visualized in routine and immunohistochemical staining in OSCC with the aid of a nomogram.

Performance of Dental Students in Understanding and Retention of Oral Pathology Concepts: A Comparative Analysis of Traditional versus Live-Field Teaching Methods.

Background: Understanding oral aspects of pathology by traditional techniques has always been a paradigm in the field of dental education. Traditional methods of teaching include interaction using black board, projectors, and alternate methods of teaching such as a student-centered approach where live-field demonstrations, audio visual aids, and student interaction are also gaining importance, ultimately promoting active education. The aim of the study was to compare live-field and static-field teaching methods in understanding and retention of the histopathological features in dental students. Methods: This was a cross-sectional analytical study, wherein a uniform cohort of III-year dental students was obtained by randomizing the study subjects. Practical classes were conducted using traditional black board/static pictures and dynamic live-field teaching comprising of microscope connected to an HD screen and projector demonstrating the preferred microscopic field. Alternately, the level of retention of knowledge was measured using customized topic-based tests. The comparison of average scores was done between live-field and static-field teaching groups using the paired t-test. Results: The test scores using the paired t-test were marginally elevated in the conventional mode of teaching; however, it varied with respect to precise topics taken using both the genres of teaching. Conclusion: A balance of both conventional and virtual teaching needs to be achieved to enhance the comprehension in student learning. Nevertheless, in the impending years, advanced research is entailed to see if the virtual mode of teaching could replace the conventional method for the advancement in the study prospects.

Recognition of lysyl oxidase as a potential predictive biomarker for oral squamous cell carcinoma: an immunohistochemical study.

BACKGROUND: Lysyl oxidase (LOX) is a copper amine oxidase which belongs to the LOX multigene family and is normally involved in cross-linking of stromal collagen fibers. LOX expression has been found to be associated with increased episodes of recurrence, metastasis and overall poor prognosis in renal cell carcinomas and melanomas. This study aimed to assess the effects of LOX on the prognosis of oral squamous cell carcinoma (OSCC), which is one of the most common cancers in India. METHODS: The immunohistochemical expression of lysyl oxidase using LOX2 primary antibody was assessed at the tumor proper, invasive tumor front and peritumoral stroma in tissue sections from 40 cases of histologically proven OSCC. RESULTS: LOX expression was elevated in OSCC patients who had lymph node metastasis and in those who died of disease. No significant variation was seen with histological grade. CONCLUSIONS: LOX has a 'pro-neoplastic' effect as it modulates the host stroma to favor increasing tumor mass and worsening prognosis. Increased expression of LOX causes increased collagen fiber cross-linkage that stiffens the stromal matrix. This increases compressive stresses contributing to tissue hypoxia that elevates Rho GTPase-dependent cytoskeletal tension leading to erratic tumor cell morphogenesis that in turn confers motility to these cells resulting in metastasis. Inhibitors of LOX can potentially down-regulate LOX levels in the tumor micro-environment by controlling tissue hypoxia and curtailing the production of hypoxic LOX molecules.

Polarizing and light microscopic analysis of mineralized components and stromal elements in fibrous ossifying lesions.

INTRODUCTION: Fibro-osseous lesions, along with few reactive lesions of the jaws exhibit an overlapping histo-morphologic spectrum with respect to the nature of calcifications and stromal components. This causes difficulty in assessing the origin, pathogenesis and diagnosis of these lesions. AIM: The present study analyses the mineralized components, cellularity, stromal density and stromal composition (nature of collagen, presence of elastic and oxytalan fibres) in cases of ossifying fibroma (OF), fibrous dysplasia (FD) and peripheral ossifying fibroma (POF). MATERIALS AND METHODS: The study included a histochemical evaluation of six cases each of FD, OF and POF. Five consecutive sections of each case were stained with hematoxylin and eosin, picrosirius red (to assess maturation of fibres in polarizing light), van Gieson (for area fraction and collagen density) and aldehyde fuchsin (for elastic and oxytalan fibres) respectively. RESULTS: Significantly higher amounts of mature bone were seen in FD while cementicles having microlamellar pattern were predominant in OF and POF (p < 0.001). Area fraction, collagen density and immature stromal fibre content was higher in POF followed by FD and OF (p= 0.039). Oxytalan and elastic fibres were absent in FD. CONCLUSION: Higher cellularity of the stroma in OF was indicative of its neoplastic behaviour. Higher composition of oxytalan and elastic fibres in OF and POF supports their periodontal ligament origin. FD was distinct with more mature fibres in a lamellated bone and absence of oxytalan fibres.