Retrospective analysis of cytogenetic and clinical characteristics on 65 patients with multiple myeloma
Authors: Yang Li , He Jingsong , Meng Xiaojian , Wei Guoqing , Wu Wenjun , Han Xiaoyan , Zheng Gaofeng , Zheng Weiyan , Ye Xiujin , Shi Jimin , Xie Wanzhuo , Zhang Jie , Huang He , Lin Maofang , Cai Zhen 
Published: October 2019

Abstract
Abstract 5075
Multiple myeloma (MM) is a malignant disorder characterized by abnormal proliferation of monoclonal, immunoglobulin producing plasma cells in the bone marrow. Studies with large samples have shown that molecular cytogenetic changes play an important role in the prognosis of MM. Based upon these findings, we tested cytogenetic aberrations of 65 patients with MM by conventional cytogenetics analysis and FISH technique in this study. Retrospective study was done on these cases for clinical features.

Methods:
This is a retrospective analysis of 65 patients with MM diagnosed between June 2007 and May 2010 including 13 relapsed cases and 52 newly diagnosed patients. Patients received bortezomib-based combination chemotherapy including bortezomib plus dexamethasone (BD) and the triplet combinations (bortezomib, adriamycin, dexamethasone (BAD), bortezomib, cytoxan, dexamethasone (BCD) and bortezomib, melphalan, prednisone (BMP) or traditional chemotherapy including doxorubicin, vincristine plus dexamethasone (VAD), melphalan plus dexamethasone (MP), melphalan, dexamethasone plus thalidomide (MPT)). To further clarify the correlation between cytogenetic and clinical features on patients with multiple myeloma, we used conventional cytogenetics analysis with R-banding technique and interphase fluorescence in situ hybridization (FISH) to describe the molecular cytogenetic characterization of bone marrow nucleated cells from 65 patients. SPSS (version 18.0) software was used for data analysis, χ2 tests or Fisher's exact test was used for betweengroup comparison of the discrete variables and Log- Rank was used for survival analysis. p<0.05 reflects the remarkable significance.

Results:
16.9% of patients (11/65) showed abnormal cytogenetic aberrations including 90.9% (10/11) cases with ultra complex aberration and complex aberration via conventional cytogenetics. In addition, we were able to show aberrations in 49.2% (32/65) of patients by interphase FISH analysis. Abnormalities of 13q14, 1q21, 14q32 and 17p13 were detected in 27.7% (18/65), 13.8% (9/65), 16.9% (11/65), and 29.2% (19/65) by FISH, respectively. 1q21 amplification is strongly associated with 13q14 mutation (P=0.008), demonstrating significant correlation between two. Abnormality of 13q14 deletion or 1q21 amplification were associated with lower levels of albumin (P<0.05). Patients with 13q14 deletion frequently had stage III disease by DS and ISS staging, and compared with patients not detected on FISH analysis, they tended to have elevated serum levels of β2-microglobulin at diagnosis (P<0.05). 17p13 deletion coexistent with 13q14 deletion frequently correlate with elevated serum levels of β2-microglobulin and advanced clinical staging. The median progression-free survival (PFS) of patients with 17p13 deletion or 17p13/13q14 aberrations were both 11.0m, significantly lower than patients with no detected abnormality (median PFS 19.0m) (P<0.05). The median overall survival (OS) of patients with FISH negtive results was 38.0m, significantly higher than those with 13q14, 14q32 or 1q21 abnormality and 17p13/13q14 or more than three abnormalities (P<0.05).

Conclusions:
This study validates myeloma cells are prone to show complex aberration and FISH is superior in the detection of cytogenetic aberrations to conventional cytogenetics analysis for patients with multiple myeloma. 1q21 had significant correlation to 13q abnormality. 17p13 deletion coexist with 13q14 deletion and 14q32 rearrangeent were used to associate with poor prognosis. 17p13 deletion or 17p13/13q14 deletion was associated with poorer PFS while abnormality of 13q14, 1q21,14q32, 17p13/13q14 or more than 3 abnormalities were correlate with poorer OS.

Disclosures:
No relevant conflicts of interest to declare.