cyfra21-1 should be CYFRA21-1 mildly elevated, whether it is serious is mainly related to the causes of CYFRA21-1 mildly elevated, can not be generalized, should be combined with the actual situation to determine. CYFRA21-1, also known as CA211, is an immune marker, mainly a soluble fragment of cytokeratin 19, which is commonly used for screening lung cancer. When inflammatory changes occur in lung tissues, under the stimulation of inflammation, the shedding of cytokeratin increases, resulting in an increase in the value of the soluble fragment of cytokeratin 19, and a mild elevation of CYFRA21-1 occurs, which is usually not serious. When cancerous changes occur in the cellular tissues of the lungs, a large number of cancer cells invade or destroy normal cells, leading to an increase in the shedding of cytokeratin, causing an increase in the value of the soluble fragment of cytokeratin 19, and a mild elevation of CYFRA21-1 occurs, and the cancerous cells cannot be completely eliminated by treatment, which is more serious at this time. Whether the mild elevation of CYFRA21-1 is serious or not, it is recommended to conduct further examination to clarify the cause of the mild elevation of CYFRA21-1 and then make a comprehensive judgment, which should also be combined with the cause of the disease and targeted treatment.