Tissue Polypeptid Antigen (TPA)

Serum frozen

TPA is a circulating complex of polypeptide fragments derived from cytokeratins 8, 18 and 19 and is detectable in most epithelial cells. It is considered a component of keratins, which form part of the intermediate filaments of normal and malignant epithelial cells. TPA is not a specific marker for any particular tumour, but indicates cell proliferation. Its clinical significance lies in monitoring disease progression and response to treatment in malignant tumours. TPA does not correlate with tumour size, but with the rate of proliferation.
Elevated:
Malignant diseases: recurrence or in the case of metastases from many malignancies (particularly bladder, lung, colorectal, testicular, breast, prostate, kidney, gastric, cervical and thyroid carcinomas)
Benign diseases: Liver diseases, pneumonia, renal failure, inflammatory gastrointestinal diseases, pancreatitis.
Note: The diagnostic sensitivity for malignant tumours is high, whilst the specificity is low; combination with other tumour markers is recommended.
See also Tumour markers