The human Penumbra gene is mapped to a region on chromosome 7 frequently deleted in myeloid malignancies

We previously cloned the murine Penumbra gene based on its differential expression in proerythroblasts/erythroblasts. Subsequently, we identified human Penumbra cDNA from a human bone marrow cDNA library and the human Penumbra gene from a BAC library. Penumbra is a new member of the tetraspanin protein family and exhibits growth-suppressive activity in vitro. In this study, we designed a human Penumbra probe contig and used fluorescent in situ hybridization (FISH) to analyze seven cases of myeloid malignancies with 7q deletions. Five patients with cytogenetic deletions involving 7q31.2∼q32 also showed deletions of Penumbra by FISH; these were not present in two patients with cytogenetic deletions not involving 7q31.2∼q32. Our findings provide the first FISH evidence supporting the mapping of human Penumbra to 7q31.2∼q32 and demonstrate the potential of the Penumbra probe in the detection of 7q31∼q32-related deletions in myeloid malignancies.