CA153 is one of many tumor markers. It is a means of breast cancer detection, but CA153 cannot be used as a standard for diagnosing a tumor. CA153, including some other tumor markers, is only used as a screening or efficacy indicator after the diagnosis of a tumor. For example, if a breast cancer patient’s CA153 is stable for a long period of time after surgery, it is considered that the condition of this breast cancer patient is stable. CA153 is a very important indicator in the process of diagnosing, treating and judging the efficacy of breast cancer, but in healthy people, CA153 is not used as a standard for diagnosing breast cancer. In healthy people, CA153 is not a criterion for diagnosing breast cancer. CA153 is more important in the all-round treatment of breast cancer patients, i.e. preoperative, postoperative and follow-up.