SCC (антиген плоскоклеточной карциномы)

Squamous Cell Carcinoma Antigen (SCCA; also reported as SCC antigen, SCC-Ag, or TA‑4) testing quantifies a tumor-associated serine protease inhibitor released by squamous neoplasms. The assay aids assessment of tumor burden and potential metastatic spread across squamous cell carcinoma sites, informs prognosis, and supports treatment planning. Serial measurement is used to monitor response to therapy and to detect recurrence following definitive treatment. The test is not intended for population screening or for establishing a diagnosis without histologic confirmation.

Squamous cell carcinoma is a malignant epithelial tumor that arises in sites such as the cervix, oral cavity, esophagus, head and neck, lung, anus, and skin. Squamous Cell Carcinoma Antigen is a glycoprotein belonging to the serine protease inhibitor (serpin) family with a molecular mass of 45–55 kDa. Under physiologic conditions, small amounts are produced within epithelial cells of the skin, cervix, and anal canal but are not released extracellularly. In squamous malignancies, secretion increases, which may contribute to invasion and metastatic behavior. The serum half‑life of SCCA is approximately 2.2 hours. Circulating SCCA concentrations correlate with cancer stage, primary tumor size, disease progression, biologic aggressiveness, and the presence of nodal or distant metastases. Among patients with cervical cancer, SCCA is detectable in about 60% overall, with reported sensitivities of roughly 10% in stage I and 80% in stage IV disease. Following tumor resection, values typically return to the reference range within 96 hours. Persistently elevated or rising concentrations after surgery suggest residual disease, progression, or relapse, and increases may precede clinical evidence of recurrence by several months in 46–92% of cases. Associations between SCCA level, stage, and survival support its use in prognostication and in selecting therapeutic strategies, including consideration of neoadjuvant or adjuvant regimens and radiotherapy, as well as for recurrence risk assessment. However, a normal SCCA result does not exclude metastatic disease, and an elevated value is not specific for malignancy and cannot establish a diagnosis on its own. Interpretation is most informative when results are compared with pre‑ and post‑treatment baselines.