The human Kid-1 homolog Tcf17 has been cloned and assigned to chromosome 5q35.3. Since the chromosome 5q22-qter region is duplicated in approximately 50% of conventional renal-cell carcinomas, it was suggested that Tcf17 is involved in the development of renal tumors. We have analyzed Tcf17 mRNA in normal kidneys and genetically distinct types of renal-cell tumor and found it expressed in nearly all normal kidney and tumor samples. There was no correlation between allelic duplication and expression of Tcf17. We did not find mutations within the coding sequences but did detect deletions within the zinc finger domain in a small proportion of RNA molecules in both normal and tumor tissues. We found ubiquitous expression of human Tcf17 as well as rat Kid-1 in different types of human and rat tissue, indicating that the putative transcription-regulating activity of this zinc finger gene, in contrast to the published data, is not restricted to the kidney. The results of expression and mutation analyses suggest that the Tcf17 gene is not involved in the development of renal-cell tumors.