Indicator Explainer
Squamous Cell Carcinoma Antigen
A secreted antigen derived from two nearly identical cytoplasmic glycoproteins of the serpin family, serpin B3 (SCCA-1) and serpin B4 (SCCA-2). These proteins are specifically expressed in normal squamous epithelia and are present at elevated concentrations in the serum of subjects with squamous cell carcinoma and certain inflammatory and autoimmune diseases. This antigen was first described in squamous cell cervical carcinoma; it is currently used as a nonspecific tumor marker for the presence, staging and monitoring of the disease course for squamous cell carcinomas of the head and neck, cervix, esophagus, anus and lung.
This page explains what the indicator is and how results are interpreted in general terms. Reference ranges depend on the laboratory, the method, and your own situation — no single “normal value” applies to everyone. This page is health information, not a diagnosis. For symptoms, treatment, or urgent concerns, contact a healthcare professional.
When it is tested
Source: National Cancer Institute, NCI Thesaurus 26.09d, C223329. NCI definition, reproduced without modification under CC BY 4.0. Source identity and definition checked automatically on 2026-10-19. No individual clinical interpretation or human reviewer is asserted.
Reading results
Reference intervals and interpretation depend on the laboratory, specimen, method and clinical context. This source definition is educational information; it does not establish a diagnosis, product approval or suitability for an individual.
Also Known As
References
- NCI Thesaurus 26.09d — Squamous Cell Carcinoma Antigen (C223329)
- Source: National Cancer Institute, NCI Thesaurus 26.09d, C223329. NCI definition, reproduced without modification under CC BY 4.0.
- A Combined Serum Biomarker Panel for Diagnostic and Prognostic Assessment in Esophageal Squamous Cell Carcinoma. — J Vis Exp, 2026-09-08 (PMID 42714055; literature)
- Differential analysis of lung adenocarcinoma and lung squamous cell carcinoma based on serum tumor markers: diagnostic performance and clinical utility. — Clinics (Sao Paulo), 2026-09-02 (PMID 42685377; literature)