A human clone corresponding to the homologue of the murine Polycomb-like gene M33 has been used to map this gene (CBX2) to human chromosomes. Both somatic cell hybrid panels and FISH on metaphase chromosomes have been used. These techniques gave a consistent localization, at the tip of the long arm of chromosome 17 (17q25). This localization, as well as the potential role of a mammalian Polycomb-like protein, suggests a potential involvement in two different pathologies: the campomelic syndrome, an inherited disorder, and neoplastic disorders linked to allele loss already described in this region.