Plasma cell labeling index correlates with deletion of 13q14 in multiple myeloma.

Multiple myeloma (MM) is characterized by complex genetic and chromosomal abnormalities involving both numerical and structural aberrations, which have clinical prognostic value. The plasma cell labeling index (PCLI) is one of the most important prognostic factors in newly diagnosed MM, and indicates plasma cell proliferative capacity. In this study, we determined the PCLI and the deletion of 13q14, retinoblastoma-1 gene (RB-1), 1p13, and 17p13, 1q21 amplification, and IgH rearrangements in 42 newly diagnosed patients with MM. A high PCLI was observed in 18 patients (42.9%), and the del(13q14) was present in 25 patients (59.5%), del(RB-1) in 23 patients (54.8%), del(17p13) in eight patients (19.1%), amp(1q21) in 23 patients (54.7%), del(1p13) in 17 patients (40.5%), and IgH rearrangements in 28 patients (66.7%). We further detected the IgH translocation partners: t(11;14)(q13;q32), t(4;14)(p16;q32), and t(14;16)(q32;q23) in 19, 15, and five patients, respectively. The PCLI had a significant correlation with del(13q14) (p = 0.006), but no correlation with other chromosome abnormalities or clinical and laboratory features (p > 0.05). The PCLI was higher among patients with del(13q14), and patients with a high PCLI had a short time to disease progression. In conclusion, PCLI is a powerful and independent prognostic parameter in newly diagnosed MM, and correlates with del(13q14).