Table 1.

Molecular cytogenetic classification and risk stratification of multiple myeloma (MM).

Cytogenetic abnormality	Gene/chromosome (s) affected	Risk stratificationa
Primary cytogenetic abnormality
Trisomic MM	Trisomies of one or more odd-numbered chromosomes	Standard risk
t (11;14) MM	CCND1	Standard risk
t (4;14) MM	FGFR3 and MMSET	High risk
MAF MM		High risk
t(14;16)	C-MAF
t(14;20)	MAF-B
Other		Standard risk
Secondary cytogenetic abnormality
Gain (1q)	1q	High risk
Del (17p)	p53	High risk
p53 mutation	p53	High risk
Other		Variable

^aPresence of any two high-risk cytogenetic abnormalities is considered double-hit MM. Presence of any three or more high-risk cytogenetic abnormalities is considered triple-hit MM.