Deletions of 12p in Hematological Malignancies

Overview

Deletions and rearrangements of the short arms of chromosome 12 are frequent chromosomal changesin patients with haematological malignancies. The loss of genetic material in tumour cells is usuallyindicative of the inactivation of genes with tumour suppressor function. The region of 12p has beenlargely studied by molecular genetic and molecular cytogenetic methods to identify the tumoursuppressor genes included in leukemogenesis. The gene TEL/ETV6 is not classical tumour suppressorgene but it is often deleted or rearranged in variety of hematological malignancies. In this study wepresent a group of 10 patients with deletion del(12)(p) found by conventional cytogenetic analyses.Patient´s diagnoses were either lymphoid or myeloid leukaemias. We applied molecular-cytogeneticmethods (fluorescence in situ hybridization- FISH) with locus-specific probe LSI TEL/AML1 to assessdeletion of TEL/ETV6 gene on 12p.To exclude translocations of 12pweuse FISH with whole chromosomepainting probe for chromosome 12 and mFISH in patients with complex karyotype. Deletion ofTEL/ETV6 was found in five of eight examined patients. No translocations of 12p were confirmed. Theregion closely linked to this gene probably contains one or more genes (tumour suppressors) whichplay the role in progression of oncogenesis. We suppose that in patients with unconfirmed deletion ofTEL/ETV6 other genes with tumour suppressor function were inactivated.

Key words:
Deletion del(12)(p), TEL/ETV6, leukaemias