Assessing the utility of CD 34 expression as an immunohistochemical marker for tumor behaviour in comparison to histopathological parameters and Tumour, Lymph nodes, Metastasis staging in oral squamous cell carcinoma.

Oral cancer remains one of the ten most prevalent cancers globally and poses a significant public health challenge, particularly in low and middle-income countries. Despite being largely preventable, its frequent diagnosis at advanced stages contributes to poor clinical outcomes and high mortality rates. Among the various forms of oral malignancies, oral squamous cell carcinoma (OSCC) is the most predominant, typically arising in the oral cavity and often evolving from potentially malignant disorders. The global incidence of oral cancer is substantial, with approximately 405000 new cases reported annually. The burden is particularly high in South Asia and certain regions of Europe, where lifestyle and environmental risk factors are prevalent. Clinically, OSCC may initially present as asymptomatic red (erythroplakia) or white (leukoplakia) patches. Without early intervention, these lesions may progress to ulcerated, indurated nodules with raised margins, indicating advanced disease. The College of American Pathologists protocol for oral squamous cell carcinoma (OSCC) outlines key histopathological parameters vital for diagnosis. Tumor size, site, and depth of invasion (DOI) are essential for AJCC 8th edition staging, with DOI strongly linked to nodal metastasis. Histologic type and grade help assess tumor aggressiveness. Perineural (PNI) and lymphovascular invasion (LVI) indicate higher recurrence risk and may warrant adjuvant therapy. Margin status is critical positive or close margins increase local recurrence. These parameters, along with nodal status and dysplasia at margins, guide early diagnosis , staging and treatment planning. Immunohistochemical approaches using markers such as pan-cytokeratin, CD34, alpha SMA, E cadherin, and vimentin have enhanced the detection and interpretation of these features, offering deeper insights into tumor behavior. Another critical factor in the progression and aggressiveness of OSCC is angiogenesis the formation of new blood vessels that support tumor growth and metastasis. Angiogenesis is commonly evaluated by measuring microvessel density (MVD), a parameter that has shown strong correlation with tumor invasiveness and poor prognosis. Immunohistochemistry is a technique for identifying cellular or tissue constituents (antigens) by means of antigen-antibody interactions. One such marker ,particularly CD34 a transmembrane glycoprotein expressed on endothelial cells are widely used to quantify MVD in lung colon, breast , stomach, prostate and bladder cancers and malignant melanomas. The disappearance of CD34 positive stromal cells are linked with the conversion of squamous intraepithelial lesions (SILs) to SCC. Complete disappearance of CD34 positive cells in the stroma in SCC indicates that they could have been converted into myofibroblasts. The appearance of CD34 positive endothelial cells plays a vital role in understanding the process of angiogenesis in oral cancer and pre-cancer.CD34 not only helps identify tumor-associated neovascularization but also serves as a valuable marker that can aid in treatment planning. To Assess the utility of  CD34 expression as an immunohistochemical marker for tumor behaviour in comparison to histopathological parameters and tumour, lymph nodes, metastasis staging in oral squamous cell carcinoma.