Molecular cytogenetic analysis of medulloblastomas and supratentorial primitive neuroectodermal tumors by using conventional banding, comparative genomic hybridization, and spectral karyotyping

Medulloblastoma displays distinct regional matrix metalloprotease expression

Matrix metalloproteases (MMPs) play an important role in tissue remodeling and neoangiogenesis during tumor progression. Little is known about the presence and regional distribution of MMPs in medulloblastomas. Based on immunohistochemical, immunocytochemical and zymographical analysis is the present study illustrates the differential pattern of MMP expression for the medulloblastoma compared to that of glioma and ependymoma. In 10 examined medulloblastoma tumors gelatinase-A was strongly expressed by clusters of tumor cells. Gelatinase-B was, similar to glioma and ependymoma, predominantly found around endothelial cells. The DAB signal for macrophage metalloelastase was seen around macrophages and matrilysin was expressed by single tumor cells. Stromelysin-1 protein was detected in medulloblastoma but not in glioma or ependymoma. From the presented data it follows that each tumor entity might display its own characteristic MMP expression pattern.

Advances in the detection of chromosomal aberrations using spectral karyotyping

Spectral karyotyping (SKY) is a powerful 24-color, whole chromosome-painting assay allowing the visualization of each chromosome in one experiment. Subtle karyotype rearrangements can be detected easily so that small translocations lead to a transition from one color to another at the chromosomal breakpoint region. SKY has enabled the elucidation of several examples of hidden or "cryptic" structural aberrations that may otherwise have been left undetected by classical cytogenetic methods. Furthermore, the chromosomal origins of abnormalities once designated "marker chromosomes" can now be determined rather than left unidentified. SKY analysis of cancer cytogenetics samples provides a much more detailed description of the highly abnormal karyotypes that characterize advanced tumors and cancer cell lines. In addition, SKY significantly adds to the power of clinical cytogenetic analysis of constitutional chromosomal aberrations by facilitating the identification of subtle structural rearrangements that may contain aneuploidy with potential pathological consequences.