20q-, deletion 20q12
Acute myeloid leukemia (AML), myelodysplastic syndrome (MDS), myeloproliferative disorder (MPD)
Fluorescence in situ Hybridization (FISH)
2.0 mL (min. 1.0 mL) peripheral blood in sodium heparin preferred, EDTA accepted
1.0 mL (min. 0.5 mL) bone marrow in sodium heparin preferred, EDTA accepted
5 mm^3 fresh tissue or 3.0 mL (min. 2.0 mL) FNA in MPLN RPMI media
Whole blood and bone marrow, ship ambient
Fresh tissue and FNA ship in a Styrofoam container with a cool/refrigerated pack (Do not allow cool pack to directly contact sample)
Clotted specimen; Specimen exposed to extreme temperature; Anticoagulant toxic to cells; Insufficient number of cells
In a normal cell, the expected pattern is the two orange signal pattern. In an abnormal cell containing the deletion, the one orange signal pattern is observed.
Deletions of the long arm of chromosome 20 represent a common chromosomal abnormality associated with myeloid disorders, in particular with myeloproliferative disorders (MPD), myelodysplastic syndromes (MDS) and acute myeloid leukemia (AML). The deletion is rarely seen in lymphoid malignancies. Other chromosome changes commonly occurring with deletion 20q are monosomy 5/5q-, monosomy 7/7q-, and trisomy 8. FISH can detect this abnormality in either interphase or metaphase cells.