The HuR gene encodes a specific RNA binding protein that is a member of the human Elav-like gene family. This family of proteins, which includes HuD, HuC and Hel-N1, is involved in cellular differentiation. Alterations of HuD and Hel-N1 structure are associated with small cell lung tumors and medulloblastomas. To investigate a possible linkage of the HuR gene to malignancy, the locus of the gene was mapped on human metaphase chromosomes. Analysis of the fluorescence signals on banded chromosomes showed that the HuR gene is localized to human chromosome 19p13.2 the cell cycle and proliferation (Levine et al. 1993; Gao et al. 1994; Liu et al. 1995; Chung et al. 1996). HuD and Hel-N1 are aberrantly spliced in human tumors yielding isoforms that are incapable of inducing differentiation (Gao et al. 1994; Antic et al. 1996). Thus it is feasible that rearrangements of the HuR gene may occur in other human tumors. In order to investigate this possibility we have mapped the HuR gene using fluorescence in-situ hybridization (FISH).