Major related tumors: squamous lung cancer, cervical cancer, esophageal cancer. Other related tumors: bladder cancer, nasopharyngeal cancer, ovarian cancer, gastrointestinal tract cancer. Other influencing factors: Hepatitis, pancreatitis, pneumonia, prostate enlargement can also be elevated. CYFRA 21-1 is the most valuable serum tumor marker for non-small cell lung cancer, especially for early diagnosis, efficacy observation and prognosis monitoring of patients with squamous cell carcinoma.CYFRA 21-1 can also be used to monitor the course of transverse muscle infiltrating bladder cancer, especially for anticipating the recurrence of bladder cancer with greater value. If the tumor is treated well, CYFRA 21-1 levels will quickly decline or return to normal levels, and changes in CYFRA 21-1 values often precede clinical symptoms and imaging during the progression of the disease. The specificity of CYFRA 21-1 for differentiation from benign lung diseases (pneumonia, tuberculosis, chronic bronchitis, bronchial asthma, emphysema) is relatively good.