Immunohistochemical evaluation of yes-associated protein molecule in the odontogenic epithelium of different histopathological variants of ameloblastoma and unicystic ameloblastoma.

Background: Ameloblastoma is one of the major odontogenic neoplasms with an invasive and recurrence potential. Its tumourigenesis and proliferative capacity can be attributed to the activation or inactivation of certain molecular signalling pathways. Hippo signalling pathway is known to regulate diverse physiological processes related to mitosis and organ growth and is an emerging tumour suppressor pathway, the dysfunction of which is implicated in various diseases including cancers. Yes-associated protein1 (YAP) and transcriptional coactivator with PDZ-binding motif (TAZ) are the downstream effectors in the Hippo cascade, which on nuclear activation leads to cellular proliferation in various tumours. Aim: The current study was undertaken to evaluate the expression of YAP in various histopathological variants of ameloblastoma and unicystic ameloblastoma. Materials and Methods: Fifty formalin-fixed paraffin-embedded tissue samples of histopathologically diagnosed cases of ameloblastoma, and 10 histopathologically diagnosed cases of unicystic ameloblastoma were obtained from the departmental archives to evaluate the immunohistochemical expression of YAP both manually and by software analysis. Results: More than 90% of cases of conventional ameloblastoma and unicystic ameloblastoma elicited positive expression of YAP. No statistical difference was found among different histopathological variants of conventional ameloblastoma. Significant difference between the means of all four quantitative score groups was observed. Conclusion: In view of the modulating effect of YAP in tumourigenesis and its higher expression in ameloblastoma, further exploration of this molecule appears to be a promising area of research.

Understanding the approach to interpretation and challenges in measurement of pathological depth of invasion in oral squamous cell carcinoma: A cross-sectional survey of oral and maxillofacial pathologists in India.

Objectives: To understand the approach to interpretation along with challenges encountered in assessing pathological depth of invasion (pDOI) in oral squamous cell carcinoma (OSCC) as per 8th Edition of TNM-AJCC staging among oral and maxillofacial pathologists in India. Method and Materials: A cross-sectional web-based survey was conducted (May 2021-October 2021) with a pre-validated 21-item questionnaire. Responses were stored in a Microsoft Excel worksheet and analysed by descriptive statistics using SPSS v 25.0. Results: About 69.7% of the 267 respondents correctly defined pDOI while 13.1% measured the same from tumour surface. Among those not reporting pDOI, one-third of respondents (36.6%) lacked requisite awareness about 8th edition staging while more than half of them (55.4%) lacked proper tools to measure. The vst majority of the oral pathologists found pDOI measurement practically challenging (85.8%), mostly with difficulty in obtaining adjacent normal mucosa (77.9%). Selection of reference points of adjacent normal mucosa was divided between deepest point of rete ridge (43.1%), the closest rete ridge (28.8%) and the tip of highest submucosal papilla (15%). Conclusion: Underreporting of pDOI was observed owing to inherent challenges in measurement, thus ostensibly substituted with tumour thickness. Elaboration on reference points of adjacent normal mucosa is awaited.

Interaction between peritumoral reactivity and histomorphological pattern of lymph node reactivity in oral squamous cell carcinoma: A host immune status indicator.

Background: The invasive tumor front (ITF) of oral squamous cell carcinoma (OSCC) and the reactive changes in regional lymph nodes (RLNs) are believed to carry integral prognostic information about the tumor's invasive capacity and insight into host immune response, respectively. Aim: This study aims to evaluate the reactivity patterns of RLNs in relation to the tumor stage, grade and various histopathological parameters at the ITF of primary tumor, in an attempt to elucidate the nature of host-immune response to tumor. Materials and Methods: Pattern of invasion (POI) using Bryne's criteria, peritumoral inflammation, and status of connective tissue (CT) stroma of 50 OSCC cases, that underwent selective neck dissection were assessed at the ITF. Immunoreactivity patterns in corresponding 450 RLNs were assessed as proposed by Tsakraklides and Ioachim. Further, 97 metastatic lymph nodes (LNs) were evaluated for degree and pattern of tumor invasion. The datasets were subjected to the Chi-square analysis. Results: There was statistically significant association (P = 0.001) of Type III and Type IV POI as well as mild peritumoral inflammation (P = 0.024) with the advanced stages of OSCC as compared to early stages. Significant association was observed between LN reactivity pattern and tumor stage (P = 0.05), with metastatic nodes exhibiting germinal center predominance (97.9%) and lymphocyte predominance (69.1%) largely observed in nonmetastatic nodes. Majority of metastatic nodes showed Grade 3 invasion (54.7%) in the form of large islands (57.7%), whereas two (2.1%) nodes were totally effaced by tumor metastasis. Statistical significance was observed between CT stroma at ITF and degree of tumor invasion in metastatic LN (P = 0.001). POI also showed significant correlation with peritumoral inflammation (P = 0.002), CT stroma (P = 0.02), and LN reactivity pattern (P = 0.03). Conclusion: This study supports the presence of a strong immunological host-tumor relationship.