Myeloproliferative Neoplasms FISH Probes

Chromosome 1 abnormalities are most frequent in the Ph‐negative MPNs polycythemia vera (PV), essential thrombocythemia (ET), and primary myelofibrosis (PMF). These alterations include duplications (1q12→1q32 in PV, 1q21–32→1q32–44 in post‐PV MF or PMF), and deletions (1p13–36→pter in PV or PMF, 1q21 in PMF).

Del5q is most tightly associated with PMF. The alteration is linked to an altered clinical and bone marrow histological phenotype, with features including more pronounced anemia and thrombocytopenia and smaller, less lobulated megakaryocytes.

Trisomy 8 occurs in 10–15% in MDS/MPN patients. The abnormality results in overexpression of several cytokine genes.

Patients with MDS or MPN usually have an indolent clinical course when del(20q) is the sole chromosomal alteration, especially when del(20q) occurs at initial presentation. However, late occurrence of del(20q) in both conditions is usually associated with greater chance of disease progression.

Complete loss of chromosome 7 or partial deletion of its long arm (del(7q) are highly recurrent in myeloid disorders, including MDS, AML, and MPN. Patients with the alteration tend to have a higher risk of disease progression, and a more complex karyotype.