A Polish family was identified in which multifocal clear cell renal carcinoma segregated with a balanced constitutional chromosome translocation, t(2:3)(q33;q21), similar to the renal cell cancer-associated t(2;3)(q35;q21) reported in a Dutch family. Bacterial artificial chromosome (BAC) contigs encompassing the 2q and 3q breakpoints were constructed and BACs crossing the breakpoints were partially sequenced. All known regional markers, genes, and expressed sequence tags (ESTs) were mapped relative to the contigs, as well as to the breakpoint sequences. Two single ESTs mapped within the 2q breakpoint BAC, whereas the repeat-rich 3q breakpoint region was gene poor. Physical mapping suggested that the 3q break was in 3q13, possibly near the border with 3q21. Physical mapping illustrated that the 2q break was closely telomeric to the 2q31 FRA2G site, consistent with the G-band assignment. Characterization of full-length cDNAs for the ESTs near the 2q break will determine if a gene(s) is altered by this familial translocation.