The 1p36.32 probe, labelled in red, is 433kb in size and covers the region between markers RH122382 and SHGC-74088. The 1q25.2 probe, labelled in green, consists of three probes (143kb, 334kb and 140kb) that cover regions including markers SHGC-75984 and SHGC-147545.
The 19p13.2 probe, labelled in green, consists of three probes (148kb, 174kb and 131kb) that cover regions including markers D19S1025 and D19S677E. The 19q13.33 probe, labelled in red, is 357kb in size and covers the region between markers RH91552 and D19S902.
Deletions of the 1p36.32 region including the TP73 (tumor protein 73) gene and deletions of the 19q13.33 region including the GLTSCR1 and GLTSCR2 (glioma tumor suppressor candidate region genes 1 and 2) genes are frequently reported in cases of glial tumours.
Astrocytomas and oligodendrogliomas are the most common gliomas that arise from glial cells. They make up about 40% of all CNS tumours1 and more than 60% of primary brain cancers2.
Concurrent losses, ‘co-deletion’, of the 1p36.32 and 19q13.33 regions are reported in approximately 80% of oligodendrogliomas, two-thirds of anaplastic oligodendrogliomas, as well as subsets of oligoastrocytomas and anaplastic oligoastrocytomas3,4; the majority of these losses have been shown to be mediated by the presence of an unbalanced t(1;19)(q10;p10) translocation. The presence of a 1p and 19q co-deletion is a strong prognostic factor in these diseases, where it is associated with improved prognosis and responsiveness to therapy5.
1p and 19q co-deletion has also been shown to occur in a subset of extraventricular neurocytomas, and may be associated with aggressive histology in these tumours6.