Molecular cytogenetic analysis of a t(7;10) in a human glioblastoma cell line.

Glioblastoma multiforme (GBM) is the most malignant glial brain tumor in humans. The fact that deleted copies of chromosome 10 are observed frequently in primary GBM tumors supports the hypothesis that one or more tumor suppressor genes located on chromosome 10 occupy crucial growth control checkpoints for glial cells. Deletion mapping in primary GBM tumors using the loss of heterozygosity (LOH) test has implicated the 10q24-10qter region as one possible site for a gene. We report here on the molecular cytogenetic analysis of chromosome 10 abnormalities in a human GBM cell line, JBSA. LOH testing showed that JBSA cells were hemizygous for chromosome 10. Molecular cytogenetic analysis showed that the undeleted homologue was involved in a reciprocal translocation t(7;10)(p21;q22). The translocation breakpoint on chromosome 10 lay within band q22 between D10S19 and D10S4. The fact that JBSA cells lack one homologue of chromosome 10 and carry a translocation breakpoint on the remaining one, proximal to the smallest region of overlap reported in primary tumor deletions, suggests that 10q22 may be another possible site for a tumor suppressor gene involved in GBM.