Fluorescence in situ hybridization based on a panel of probes for detection of common cytogenetic abnormalities in multiple myeloma / 实用医学杂志

Objective To evaluate the advantages of plasma cell enrichment combined with fluorescence in situ hybridization (FISH) based on a panel of probes by the conventional cytogenetic (CC) analysis.Methods Fresh heparinized bone marrow samples were collected by bone marrow biopsy.Plasma cells were enriched in BM samples using a magnetic cell-sorting procedure to select CD138+ cells.The common chromosome abnormalities of MM were detected by FISH based on a panel of probes and CC analysis after short-term culture of the BM cells,in order to compare the differences between these two methods for the frequency of common cytogenetic abnormalities.Results 72 of 95 (75.8％) MM patients were found to carry clonal chromosome abnormalities by FISH.And RB 1 deletion was the highest at 44.2％ (42/95) followed by CKS1B (1q21) amplification (42.1％).The frequencies of CDKN2C (1p32) deletion,TP53 deletion,IGH/CCND1 and IGH/FGFR3 were 8.4％ (8/95),12.6％ (12/95),14.7％ (14/ 95) and 14.7％ (14/95),respectively.IGH/MAF was negative.Thirty-two of 95 (33.7％) patients were found to carry clonal aberrations by CC analysis.The frequency of chromosome abnormalities detected by FISH was significantly higher than CC analysis (75.8％ vs 33.7％,P =0.000).Conclusion Plasma cell enrichment combined with FISH based on a panel of probes can greatly increase the frequency of chromosome abnormalities,which provides cytogenetic basis for risk stratification and prognosis of MM patients.

Routine laboratory diagnosis of chromosome aberrations in multiple myeloma.

Multiple Myeloma (MM) is a Plasma Cell (PC) malignancy characterized by proliferation of differentiated B cells mainly in the bone marrow. Genetic abnormalities are powerful prognostic factors in MM for risk stratification and therapeutic strategies. The standard diagnostic tests to detect genetic abnormalities in MM include Conventional Cytogenetic Analysis (CCA) and Interphase Fluorescence In Situ Hybridization (FISH). Due to the low proliferative activity of the abnormal clone, only 30-50% of newly diagnosed MM demonstrate an abnormal karyotype by CCA. CCA is a biological test which requires dividing cells for analysis. The t(4;14) translocation which carries a poor prognosis is cryptic and cannot be detected by CCA. These limitations were overcome partly by the incorporation of interphase FISH as a routine diagnostic test in MM. There is an international consensus that FISH should be performed in all newly diagnosed MM to detect high-risk genetic abnormalities. FISH testing must be done on purified PCs or by simultaneous labeling of cytoplasmic immunoglobulin light chain to allow identification of PCs. The minimum essential abnormalities to test for are t(4;14), t(14;16) and del(17)(p13). However, there is no consensus on the optimal protocol for CCA and interphase FISH. We review here the types of chromosomal aberrations found in MM, the prognostic significance of these abnormalities, methodologies in CCA to improve on the low yield of abnormal karyotypes, and protocols in interphase FISH.