Evidence of Focal Genetic Microheterogeneity in Glioblastoma Multiforme by Area-Specific CGH on Microdissected Tumor Cells

Abstract

The term "multiforme" in glioblastoma multiforme (GBM) indicates the highly variable histomorphology that cannot be addressed by studies on homogenized tissue probes. In order to relate genetic findings with histomorphologically distinct areas we used microdissection to procure defined cell populations from microscopic tissue sections under direct visualization. Formalin-fixed and paraffin-embedded tissue sections of 10 GBM were evaluated for intratumoral genetic heterogeneity by microdissection of multiple areas of 20-50 tumor cells and DOP-PCR of DNA isolated from the dissected cell groups, followed by comparative genomic hybridization (CGH). Microdissected cells from histomorphologically normal extratumoral blood vessels from the same slides served as controls. The individual tumors showed variable combinations of primary chromosomal gains and losses common to all studied areas of a given case along with secondary, area-specific additional aberrations. CGH displayed a wider variety of chromosomal aberrations than metaphase cytogenetics of cell cultures from the same tumors. The most frequent aberrations observed were previously unperceived gains on chromosomes 4q (8/10) and 5q (5/10). Other nonrandom aberrations were gains on 12q (6/10), 13q (6/10), and 7 (5/10), and losses of 22 (5/10). Amplifications on 7p were intratumorally heterogeneous and only found in single areas of 2 tumors. In contrast to normal extratumoral vessels, vascular proliferates in most cases demonstrated chromosomal aberrations (CGH) which were partially different from the aberrations observed in the tumor itself. The described method gives evidence of considerable intratumoral genetic heterogeneity in GBM and provides a sensitive tool for the detection of quantitative chromosomal changes that are present only regionally within a given tumor.

Vitamin D3 Metabolism in Human Glioblastoma Multiforme: Functionality of CYP27B1 Splice Variants, Metabolism of Calcidiol, and Effect of Calcitriol

“…The CYP27B1 mRNA expression was elevated in the majority of glioblastoma multiforme cell cultures in comparison with the corresponding tumor biopsy. This difference may be in part explained by the high heterogeneity of glioblastoma multiforme tissues in comparison to cell cultures that are less heterogeneous due to clonal selection (30). Selective pressure in favor of an elevated CYP27B1 expression in glioblastoma multiforme cell cultures may indicate a potential significance of CYP27B1 activity for neoplastic growth in glioblastoma multiforme.…”

Autoantibodies against GLEA2 and PHF3 in glioblastoma: Tumor‐associated autoantibodies correlated with prolonged survival

“…Several characteristics of glioblastoma multiforme complicate the introduction of specific markers, especially the high intratumoral heterogeneity, presumably associated with a complex antigen pattern. 7,8 To identify novel prognostic markers, we utilised serological identification of recombinantly expressed tumor antigens (SEREX), which is based on an effective B-cell response of the cancer patient. 9 SEREX is a powerful method to identify tumor autoantibodies in patient sera as shown for various different tumor types including glioblastoma.…”

p15 promoter methylation - A novel prognostic marker in glioblastoma patients

“…1). Taking into account the heterogeneity of these diffusely and infiltrating growing gliomas (33,34), this observation arises most likely from a different tumor cell population and from normal cells contaminating the tumor sample. Nevertheless, this heterogeneous methylation pattern may also result in different amounts of MGMT and therefore affect chemotherapy response which would be interesting to investigate in a larger patient cohort.…”