Tartrate-resistant acid phosphatase (TRAP) as a serum marker for bone resorption in breast cancer patients with bone metastases.

BACKGROUND

A novel immunoassay specific for the osteoclast-produced tartrate-resistant acid phosphatase TRAP isoform 5b was developed some years ago. By means of this assay, the usefulness of serum TRAP in monitoring the response to palliative treatment with clodronate in breast cancer patients with bone metastases was studied. Serum TRAP was examined for correlation with the activity of bone osteoclasts in these patients.

MATERIALS AND METHODS

Seventeen patients took part in this study taking 1600 mg clodronate daily as a tablet for five months. Eleven of these patients were evaluated.

RESULTS

TRAP activity correlated well with the grade of bone metastases and with the number of locations in the body. During the therapy with clodronate, TRAP activity in serum decreased.

CONCLUSIONS

We conclude that the measurement of TRAP is useful in monitoring treatment with bisphosphonate clodronate in patients with bone metastatic breast cancer.