Gain of 1q21 is an unfavorable genetic prognostic factor for multiple myeloma patients treated with high-dose chemotherapy.

The prognostic significance of 1q21 gain, del(13)(q14), del(17)(p13), t(4;14)(p16.3;q32), and t(11;14)(q13;q32) detected by interphase fluorescein in situ hybridization (FISH) was studied in a cohort of 91 patients with newly diagnosed multiple myeloma (MM). 1q21 gain was detected in 37 of 91 patients (40.7%). In comparison with patients lacking 1q21 gain, patients with 1q21 gain had significantly shorter progression-free survival (PFS) (14.9 versus 27.4 months; P = .044) and worse 4-year overall survival (OS) (40.1% versus 76.2% of patients; P = <.001). PFS or OS were not influenced by the presence or absence of the other studied chromosomal abnormalities. Although the occurrence of 1q21 gain correlated with deletion of 13q14, the presence of 1q21 gain can be considered an independent prognostic factor, as no impact of del(13)(q14) as an isolated chromosomal abnormality on either PFS or OS has been observed. In comparison with patients lacking 1q21 gain, patients with 1q21 gain were significantly more likely to discontinue the preplanned treatment protocol because of disease progression or death. We conclude that 1q21 gain defines a prognostically unfavorable group of MM patients.