Table 3.

Revised cytogenetic risk stratification for primary myelofibrosis

Cytogenetic risk category	Specific abnormalities	Median survival
Favorable risk	Normal karyotype Sole 20q− Sole 13q− Sole +9 Sole –Y Sole sex chromosome abnormality Sole chromosome 1 translocation/duplication	4.4 years
Unfavorable risk	Sole +8 Sole 7q− Sole translocations not involving chromosome 1 Two abnormalities not including a VHR abnormality Single/multiple 5q− abnormalities Complex karyotype without a VHR abnormality Monosomal karyotype without a VHR abnormality Sole abnormalities not otherwise classified	2.9 years
Very high risk (VHR)	Single/multiple monosomy 7 Single/multiple inv(3)/3q21 abnormalities Single/multiple i(17q) abnormalities Single/multiple 12p−/12p11.2 abnormalities Single/multiple 11q−/11q23 abnormalities Single/multiple autosomal trisomies other than +8 or +9 (e.g., +21, +19)	1.2 years