B-cell lymphoma/leukemia-2 genes lend its name to the oncoprotein Bcl-2. It is present in cases of oral squamous cell carcinoma (OSCC) and it negates apoptosis. In normal apoptosis, the dead cells are eliminated and new cell growth takes place. OSCC is the most common type of malignant tumour of the oral cavity. Test for Bcl-2 gene component expression is done using immunohistochemistry for patients with oral precancer and cancer. It is because of Bcl-2 that oral epithelial dysplasia progresses to squamous cell carcinoma. The testing technique, immunohistochemical staining is commonly used in the diagnosis of abnormal cell growth. The distribution and localization of biomarkers like Bcl-2 in different parts of the biological tissue help to confirm oral precancer and cancer.