CK18M65 test belongs to immunohistochemistry and is currently used clinically for the diagnosis and differentiation of visceral adenoepithelial tumors, determination of the primary site of metastatic malignant tumors, and so on. CK18M65 test belongs to immunohistochemistry, and its current applications include diagnosis and differentiation of malignant tumors, determination of the primary site of metastatic malignant tumors, detailed pathological typing of certain types of tumors, and helping doctors to find tiny metastases. Clinically, according to immunohistochemistry, more accurate and efficient treatment plans can be established, and the value of immunohistochemistry in the diagnosis and differentiation of tumors has been recognized by the medical profession. If there is any abnormality in the results of this test, it is recommended to consult the doctor in time and carry out standardized treatment under the guidance of professional doctors.