Reduced nm 23-H1 messenger RNA expression in metastatic lymph nodes from patients with papillary carcinoma of the thyroid.

The nm 23 gene product, which possesses nucleoside diphosphate kinase activity, is a possible mediator of cancer cell invasion and metastasis. It has been divided into two distinct gene products, nm23-H1 and nm23-H2. We have developed a method for detecting nm 23-H1 and nm 23-H2 RNA using the polymerase chain reaction, based on the amplification of complementary DNA copies of nm 23-H1 and nm 23-H2 RNA. Using this method, the nm 23-H1 and nm 23-H2 messenger (m)RNA levels in 35 thyroid papillary carcinomas, 11 metastatic lymph nodes from patients with thyroid papillary carcinomas, five thyroid follicular adenomas, and three normal thyroid tissue samples were studied. Both nm 23-H1 and nm 23-H2 mRNA were expressed ubiquitously in normal and malignant thyroid tissues. However, in metastatic lymph nodes no (3 of 11) or weak expression (8 of 11) of nm 23-H1 mRNA was observed, the extent of which was inversely proportional to the degree of cancer cell occupancy, whereas nm 23-H2 mRNA was expressed and the levels were similar to those in other tissue tested. These results show that nm 23-H1 only may play a role in cancer cell invasion and metastasis although the exact mechanisms involved have yet to be elucidated.