J. Bostrom et al., MUTATION OF THE PTEN (MMAC1) TUMOR-SUPPRESSOR GENE IN A SUBSET OF GLIOBLASTOMAS BUT NOT IN MENINGIOMAS WITH LOSS OF CHROMOSOME ARM 10Q, Cancer research, 58(1), 1998, pp. 29-33
The PTEN (MMAC1) gene, which has been identified as a tumor suppressor
gene at 10q23.3, is mutated in multiple malignant tumors, including g
lioblastomas [J. Li et al., Science (Washington DC), 275: 1943-1947, 1
997; P. A. Steck et al., Nat, Genet., 15: 356-362, 1997], Among tumors
of the central nervous system, loss of 10q is not restricted to gliob
lastomas but is also common in atypical and anaplastic meningiomas. Th
erefore, we have investigated 36 glioblastomas and 34 meningiomas (2 b
enign, 17 atypical, and 15 anaplastic meningiomas) for Loss on 10q, as
well as deletion, mutation, and expression of PTEN, Analysis of eight
microsatellites from 10q revealed loss of heterozygosity (LOH) in 25
of 36 glioblastomas (69%), Twenty-three of these tumors demonstrated L
OH at all informative loci, Two glioblastomas showed LOH restricted to
markers located distally to PTEN, with breakpoints mapping telomeric
to D10S541 and D10S185, One glioblastoma demonstrated evidence of homo
zygous deletion of PTEN by differential PCR analysis, PTEN mutations w
ere detected in 9 of 36 glioblastomas (25%). Seven of these tumors sho
wed LOH at all informative loci from 10q, indicating complete loss of
wild-type PTEN. Although loss of 10q was detected by comparative genom
ic hybridization and/or LOH analysis in 14 of the 34 meningiomas inves
tigated (41%), none of these tumors showed evidence of PTEN mutations
or homozygous gene deletions, Our findings corroborate that PTEN is in
activated in a subset of glioblastomas. However, the lack of detectabl
e PTEN alterations in a considerable fraction of glioblastomas and all
meningiomas with 10q loss strongly supports the hypothesis that at le
ast one additional tumor suppressor gene is located on 10q.