Major related tumors: squamous carcinoma of the cervix. Other related tumors: squamous carcinoma of the lung, squamous carcinoma of the head and neck, esophageal carcinoma, and squamous cell carcinoma of the vulva. Other influencing factors: SCCA values are elevated in patients with hepatitis, cirrhosis, pneumonia, and tuberculosis. Squamous cell carcinoma antigen (SCC) is a tumor marker that has good specificity and was first used to diagnose squamous carcinoma.SCC inhibits cell regulation and participates in the differentiation of squamous epithelial layer in normal squamous epithelial cells and in tumor growth in tumor cells.It is useful in the diagnosis and monitoring of all cancers of squamous epithelial cell origin, such as: cervical cancer, lung cancer (non-small cell lung cancer), head and neck cancer, esophageal carcinoma, nasopharyngeal carcinoma, and squamous cell carcinoma of the vulva. Patients with these tumors have elevated serum concentrations of SCC, which increase with disease stage. It is used clinically to monitor the efficacy, recurrence, and metastasis of these tumors and to evaluate the prognosis. It has high diagnostic value for cervical cancer: sensitivity for primary squamous cervical cancer is 44%-69%; sensitivity for recurrent cancer is 67%-100% and specificity is 90%-96%; its serological level correlates with tumor development, degree of invasion and whether it is metastatic. SCC concentration decreases significantly after radical cervical cancer surgery; it can indicate recurrence at an early stage, and the increase of SCC concentration in 50% of patients precedes the clinical diagnosis of recurrence by 2-5 months, which can be applied as an independent risk factor. Adjuvant diagnosis of squamous lung cancer: the positive rate of squamous lung cancer is 46.5%, and its level correlates with the degree of tumor progression; it can improve the sensitivity of diagnosis of lung cancer patients with the combination of CA125, CYFRA21-1 and CEA. Prediction of esophageal squamous carcinoma and nasopharyngeal carcinoma: the positivity rate increases with disease progression, and for advanced stage patients, its sensitivity can reach 73%, and the combined detection of CYFRA21-1 and SCC can improve the sensitivity of detection. the positivity rate of stage III head and neck cancer is 40%, and increases to 60% at stage IV. Diagnosis and monitoring of other squamous cancers: head and neck cancer, vulvar cancer, bladder cancer, anal canal cancer, skin cancer, etc.