Objective: To summarize the clinical significance and 13q- characters of 100 multiple myeloma (MM) patients detected by interphase fluorescence in situ hybridization (i-FISH).
Methods: Specimens of bone marrow were collected from 100 patients with MM who visited the Institute of Hematology and Blood Diseases Hospital, Chinese Academy of Medical Sciences in Tianjin, China. Chromosome R-banding analysis and i-FISH were conducted.
Results: (1) i-FISH was used to investigate 100 patients with MM, whose median age was 56 years and 19 (19.0%) cases showed chromosome 13q deletions/monosony13 (Delta13); conventional cytogenetics (CC) revealed informative MM karyotypes in 24 patients (24.0%),with Delta13 in 10 (10.0%) of them. Detection rate of the two methods had no significant difference (P = 0.053), but in newly diagnosed patients i-FISH was much more sensitive than CC test (Detection rate, 25.3% vs 9.3%, P = 0.008). (2) Among the whole cases, 93 of them had complete follow-up information. The overall survival (OS) of the 93 patients was 41 (1-69) months. Univariate analysis showed that the positive rate of Delta13 detected by i-FISH >50%, clonal chromosome 13 abnormality (C13A), nonhyperdiploidy, Delta13 detected by both CC and i-FISH, beta2-MG > or = 3.5 mg/L were associated with significantly shorter OS. Multivariate analysis indicated that the positive rate of Delta13 detected by i-FISH > 50% and beta2-MG > or = 3.5 mg/L were the independent unfavorable factors. (3) According to the two independent unfavorable factors mentioned above, we divided the 93 patients into three groups: low-risk, standard-risk and high-risk. And there were significant differences of OS among the 3 groups (P < 0.05).
Conclusion: (1) FISH studies demonstrate a high sensitivity at detecting chromosome 13 abnormality and should be used in the routine evaluation of MM. (2) The positive rate of Delta13 detected by i-FISH > 50% and beta2-MG > or = 3.5 mg/L were the independent adverse prognostic factors.