Immunocytochemical analysis of lymph node negative breast tumors was graded as the percent of tumor staining positive for nm23 and the intensity of staining.
Significantly, a high occurrence of alterations in microsatellite polymorphisms at the ANK1, D8S135 and LPL loci of chromosome 8p (46-54%), the D2S119 locus of chromosome 2p (56%), the D10S197 locus at chromosome 10p (88%), and the nm23-H1 locus of chromosome 17q21.3 (46%) were observed in breast tumors.
Northern blot hybridization of nm23-H1- and nm23-H2-specific probes to breast tumors and cell lines indicated that nm23-H1 expression was reduced in high metastatic potential tumor cells to a greater extent than nm23-H2.
We conclude that nm23 RNA levels are differentially expressed in human breast tumors, and that low nm23 RNA levels are associated with histopathological indication of high metastatic potential.