Immunohistochemical Comparison of Ki-67 and MCM-3 in Odontogenic Cysts: An Observational Study.

Odontogenic cysts are a diverse group of pathologic entities with different proliferation potential, leading to variations in their biological behavior. One of the most cited proliferation markers used in diagnostic histopathology is Ki-67. Another group of proteins recently investigated is minichromosome maintenance (MCM-3) and its expression has been evaluated in several odontogenic lesions but the results were controversial. Thus, the present study endeavored to compare the expression of MCM-3 and Ki-67 in odontogenic cysts. Furthermore, a pioneer attempt was made to evaluate the sensitivity of these markers to inflammation. A total of 101 cases (37 dentigerous cysts, 37 odontogenic keratocysts, and 27 radicular cysts) were included. Immunohistochemical expression of Ki-67 and MCM-3 were investigated using a labeling index (LI). In addition, they were scored for inflammation, followed by correlation with both markers. The data obtained were subjected to statistical analysis ( P <0.05). Overall, a higher LI of MCM-3 than Ki-67 was obtained in all study groups along with a positive correlation of Ki-67 LI with inflammation. Thus, MCM-3 proteins proved to be a more accurate means to determine the proliferation potential and were not sensitive to external stimuli like inflammation than conventional markers, such as Ki-67.

Histopathological evaluation of minor salivary gland aberrations in oral squamous cell carcinoma.

Background: Oral squamous cell carcinoma (OSCC) is one of the most established oral cancers in India, with high morbidity and mortality. The most common etiological agent associated with it is tobacco (in any form), which releases chemical carcinogens that affect not only the oral epithelial lining but also deep stromal structures such as minor salivary glands. They may cause changes in ductal or acinar part of gland depending on tumor grade, thus providing a fertile soil for tumor growth and recurrence. Aims and Objective: To observe the frequency of minor salivary gland changes associated with tobacco as well as to measure the length and depth of ductal involvement in routine tissue sections of OED and OSCC. Materials and Methods: A total of 94 hematoxylin and eosinstained archival slides which included cases of well, moderate, and poorly differentiated OSCC and oral epithelial dysplasia were histopathologically evaluated to observe changes in different components of minor salivary gland. Ductal hyperplasia, ductal metaplasia, mucous pooling within duct, acinar degeneration, pattern of malignant cell invasion (single/clusters), inflammatory infiltrate, eosinophilic cuffing around the gland, and glandular/vascular involvement were evaluated in each slide and correlated with different grades of OSCC. Results: Ductal hyperplasia, inflammatory cell infiltrate, mucous pooling, and pattern of malignant cell infiltration came out to be statistically significant with the highest percentage of changes being observed in poorly differentiated squamous cell carcinoma > moderately differentiated squamous cell carcinoma> well differentiated squamous cell carcinoma>oral epithelial dysplasia. Further, the results of this study suggest that extension of dysplasia or squamous cell carcinoma from overlying oral epithelium along salivary gland ducts is an uncommon finding. Conclusion: Hence, histopathological interpretation for OED and OSCC should also include changes related to associated minor salivary gland tissue as detection and eradication of the putative precursors are the best way of decreasing the overall morbidity caused by tumors.

The road less travelled: Skeletal muscle invasion in oral squamous cell carcinoma.

Introduction: Oral squamous carcinoma (OSCC) is one of the most challenging global constraint and currently the third most common cancer in India. Malignant cells exhibit anomalous morphological characteristics like increased and abnormal mitosis which might suffice as a prognostic indicator. Skeletal muscles present in close approximation with the oral epithelium are often encountered by the tumor cells of OSCC which is an uncharted territory and might serve as a critical parameter in assessing the outcome of OSCC. Amalgamation of mitotic count and skeletal muscle invasion can put forward cogent paths in discerning the behavior of these lesions. Material & methods: A total of 60 histopathologically diagnosed cases of well, moderately and poorly-differentiated OSCC cases were obtained from the archives. Hematoxylin and eosin-stained slides were examined for Mitotic count and Skeletal muscle invasion. Results: There was a statistically significant increase in Mitotic count from well-differentiated to poorly-differentiated OSCC. Despite the statistically insignificant difference there was a distinct rise of skeletal muscle invasion from well-differentiated to poorly-differentiated OSCC. Conclusion: The rise in mitotic count with increasing grades of OSCC suggests an increase in their proliferation rate. Owing to the marked elevation of skeletal muscle invasion in higher grades of OSCC, we can assume it to be a reliable predictor of aggressiveness and outcome. Further studies with a uniform sample size and site specificity might help in solidifying their role in assessing the prognosis of OSCC.