FISH mapping of i(7q) in acute leukemias and myxoid liposarcoma reveals clustered breakpoints in 7p11.2 : implications for formation and pathogenetic outcome of the idic(7)(p11.2)

• Isochromosome 7q - i(7q) - is seen in a wide variety of hematologic malignancies and solid tumors, often as a secondary change to a characteristic primary translocation. Despite its high frequency, nothing is known about the formation and the pathogenetic outcome of this abnormality. To address these issues, we performed a detailed fluorescence in situ hybridization (FISH) investigation of four acute lymphoblastic leukemias, one acute myeloid leukemia, and two myxoid liposarcomas with i(7q). Using FISH with bacterial artificial chromosomes (BACs) mapping between 7p12.2 and 7q11.2, the breakpoints (BPs) in all seven cases were shown to cluster to an approximately 340 kb segment at 7p11.2, covered by the overlapping BAC probes RP11-760D2 and RP11-10F11. Thus, the i(7q) should formally be designated idic(7) (p11.2). In one of the cases, FISH with fosmids could narrow down the BP further to an 80-kb sequence delineated by G248P81983A10 and G248P8793H7. No known genes are located in the 340-kb BP cluster region, indicating that the idic(7)(p11.2) does not result in a fusion or deregulation of genes in this segment. The pathogenetically important outcome is thus likely to be an altered gene expression because of copy number changes. The clustering of breakpoints might be due to frequent intrachromosomal duplicons in the BP region.

Ämnesord

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper -- Medicinsk genetik (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine -- Medical Genetics (hsv//eng)

MEDICIN OCH HÄLSOVETENSKAP  -- Klinisk medicin -- Cancer och onkologi (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Clinical Medicine -- Cancer and Oncology (hsv//eng)

Nyckelord

Preschool

Aged

Adult

Chromosomes

Chromosome Breakage: genetics

Human

Female

Pair 7: genetics

In Situ Hybridization

Humans

Isochromosomes: genetics

Fluorescence

Liposarcoma

Myxoid: genetics

Leukemia: pathology

Karyotyping

Leukemia: genetics

Child

Acute Disease

80 and over

Myxoid: pathology

Male

Middle Aged

Research Support

Non-U.S. Gov't

Adolescent

Publikations- och innehållstyp

art (ämneskategori)

ref (ämneskategori)