Immunohistochemistry for Cyclin D1 (CCND1) aims to detect the overexpression of Cyclin D1 protein, a regulator of the cell cycle. This overexpression is a distinctive molecular and histological feature of several tumors, most notably Mantle Cell Lymphoma (MCL) due to the t(11;14) genetic translocation, as well as Oncocytoma of the salivary glands.