NM23 PROTEIN IN NEOPLASTIC AND NONNEOPLASTIC THYROID TISSUES

The expression of nm23 gene products has been associated with a lower metastatic potential and better outcome in malignant tumors. We have u sed immunohistochemistry to study the expression of nm23 protein in th yroid tissues from 101 patients consisting of 78 malignant neoplasms, 13 adenomas, and 10 other benign conditions. Cytoplasmic staining for nm23 protein was identified in normal tissues and in most benign and m alignant lesions and did not correlate with either histological type o r clinical outcome. Nuclear staining was seen in 93% of normal tissues and in 29% of primary carcinomas of the thyroid and was associated wi th a longer disease-free survival (P = 0.03). Membranous staining was present in some tumors but absent in normal thyroid. In conclusion, nm 23 protein has a combined pattern of distribution among subcellular co mpartments in thyroid tissues. Although there was no significant assoc iation between cytoplasmic or membranous expression and histological t ype of tumor or survival, nm23 nuclear expression may be a useful mark er in assessing the evolution of thyroid tumors.