Immunohistochemical staining, which is the application of the reaction principle of specific binding of antigen and antibody in immunology, generally takes the method of biotin-labeled antibody to show the antigen in the tissue for the study of localization, characterization and relative quantification of antigen. The clinical choice of whether to add immunohistochemistry is based on the condition of the HE section. In the more typical cases that are clear without examination, immunohistochemistry is not necessary. In cases where the diagnosis is not clear, additional immunohistochemistry is needed to further confirm the tumor type and to avoid affecting the patient’s treatment.