Clinical Biochemistry

Squamous cell carcinoma associated antigen (SCC)

Test Background
SCC is a subfraction of TA-4, a tumour-associated antigen. TA-4, obtained from squamous cell cancer tissue of the uterine cervix, has been characterised as a glycoprotein with a molecular weight of 48 kDa. SCC is a member of the family of serine proteases. Several studies have shown that serum SCC levels reflect the extent of disease in women with cervical squamous cell cancer, and can be useful as an adjunct in predicting prognosis, detecting recurrence and monitoring disease status. The clinical sensitivity of SCC antigen serum levels for primary cervical cancer increases from approximately 30 % in stage I to 90 % in stage IV disease. SCC antigen has been studied in other squamous cell malignancies, including those of the lung, oesophagus, head and neck, anal canal and skin. In general, a pattern similar to that seen with squamous cell carcinoma of the uterine cervix is seen with these tumours, ie. the more advanced tumour stages are reportedly associated with higher SCC antigen levels. Researchers have reported that measurement of the antigen, in serial determinations, may indicate disease recurrence, residual disease following treatment and response to therapy.

Clinical Indications

• Cervical cancer
• • Diagnosis: due to limited sensitivity and specificity, single measurements of SCC are not recommended for screening purposes. At initial diagnosis, approximately 60 % of patients have elevated levels of SCC.
  • Prognosis and monitoring: pre-treatment serum SCC concentration correlates significantly with tumour stage and size. High SCC levels are associated with the presence of lymph node metastases. Elevated pre-treatment SCC level is an independent risk factor for poor prognosis.
  • Treatment: SCC serum concentration correlates with the disease’s responsiveness to treatment. Surveillance: serum SCC has a sensitivity of approximately 70 % and specificity of 90 % in detecting recurrent disease.

• Lung cancer

• • Diagnosis: although single measurements are not suitable for screening, SCC has specificity for squamous cell cancer and can be used for subtyping. SCC may be used in combination with CEA and CYFRA for differential diagnosis of non-small cell lung cancer (NSCLC).
  • Prognosis and monitoring: SCC has reported prognostic value in NSCLC.

Reference Range

Sample Required
SST (gold top) preferred, serum (red top) accepted

Sample Volume
0.5 mL

Turnaround Time
4 days

Notes
Abbott Architect assay