IHC has became an indispensable tool adjunct to the conventional pathology in daily practice. This technique is called immunohistochemistry because it was combined by two aspects including immunology and histochemistry applied directly on the tissue (taken from the patient lesion) section embedded in paraffin. This technique is one of the most modern and useful method by using the markers (antibody) to find out the specific tiny molecules called antigens of the cell in tissue for the tumor diagnosis. The most common aim of diagnosis is to determine the cell type. Recently the newer markers also help the prognosis besides the classic criteria like histopathological grade, TNM (Tumor, Node, Metastasis)… and treatment in which the new one is called molecularly targeted therapy. Although IHC is very necessary for all the above mentioned aims but in order to determine a lesion as definitely benign or malignant we have to mainly base on the standard H.E histopathology up to now. For all the benefits, the basic pathology knowledge of each tumor and the aim of each marker used in IHC are both important and combinative.