Somatic allelic deletion of nm23 in human cancer

Tumor progression to the metastatic phenotype is accompanied in certain cell types by reduced expression of the nm23 gene. We have localized human nm23-H1 to chromosome 17 by somatic cell hybrid analysis. Regional localization in the CEPH database and in situ hybridization is reported. Somatic allelic deletion of nm23-H1 was observed in human breast, renal, colorectal, and lung carcinoma DNA samples, as compared to DNA from matched normal tissues. A homozygous deletion of nm23-H1 was observed in a lymph node metastasis of a colorectal carcinoma, indicating that nm23-H1 can be recessively inactivated. The data identify nm23-H1 as a novel, independent locus for allelic deletion in human cancer, a characteristic shared with previously described suppressor genes.