Malignant blood diseases may be classified:
Myeloproliferations : quantitatives anomalies of the myeloid lineage.
Hybrid genes, with the involvement of :
Myelodysplasia: cells look "bizarre", dysplastic. Classified according to the FAB:
It is the most common structural rearrangement in myelodysplastic syndromes (MDS) and in acute myeloid leukemias (AML); del (5q) is accompanied with given clinical and haematological features. We herein summarize these three pictures as:
Massive proliferation of myeloid precursors; with a hiatus aspect in the maturation pyramid and entry of immature cells into the bloodstream. The new WHO/OMS classification replaces and completes the FAB classification (M1 to M7).
FAB:
Hundreds of chromosome rearrangements are not listed by the WHO in its "first group"; for example: t(9;22)(q34;q11) (very rare in AML; hybrid gene BCR-ABL1, poor prognosis).
This category is defined by the presence of multilineage dysplasia (in contrast with the t(15;17), for example, which affects only promyelocytes). Chromosomes abnormalities:
"Secondary " to exposure to toxins (ex: chemotherapy, radiotherapy, professionnal expositions (benzene), radiations, smoking. Chromosomes anomalies: del(5q) / -5, del(7q) / -7 after alkyliting agent exposure, long-term latency (years). 11q23 (MLL) rearrangements, 21q22 (RUNX1) rearrangements, others after antitopoisomerase II exposure; short-term latency (often some months). Very poor prognosis.
(Note: 11q23 rearrangements are also -and more often- found in de novo leukaemia)
AML M1 to M7, according to the FAB clasification + M0 (undifferentiated) and biphenotypic acute leukaemias (AML + ALL)
ex: t(11;14)(p13;q11), t(8;14)(q24;q11) and t(10;14)(q24;q11)
Sarcomas: it is an heterogeneous group, of many malignant tumours, often the diagnostic is hard to reach; however, a number of these tumours present a specific translocation; which can be of great help for diagnostic ascertainement. A few examples:
Carcinomas: There can be specific translocations, e.g.:
Karyotype:
Genes Implicated:
Some rare genetic diseases:
Autosomal recessive; q2 = 1/40 000. Clinics:
Autosomal recessive; q2 = 2/100 000. Clinics:
Autosomal recessive; q2 = 0,4/100 000.
Cancer prone disease at increased risk of the cancer of the retina called retinoblastoma.
Huret JL Huret JL
Atlas of Genetics and Cytogenetics in Oncology and Haematology 2000-06-01
Chromosomes, Leukemias, Solid Tumors, Hereditary Cancers
Online version: http://atlasgeneticsoncology.org/teaching/30077/gene/40/js/haematological/2072/bcldclassifid2072