A Rare Case of Triple‐Hit Ultra‐High‐Risk Multiple Myeloma Harboring t(4;14), t(14;20), and Gain(1q)

Immunoglobulin heavy chain (IGH) rearrangement involving chromosome 14q32 and hyperdiploidy are considered the primary cytogenetic abnormalities in multiple myeloma (MM). Due to the genomic instability, some secondary cytogenetic abnormalities often occur during the course of the disease, including gain(1q), del(1p), gain(11q), del(12p), del(13), del(16q), del(17p), and so on [1]. The identification of genetic abnormalities is of great importance in assessing the prognosis of MM patients. High-risk chromosome abnormality (HRMM) is defined as the presence of any of the risk factors t(4;14), t(14;16), del(17p), and gain/amplification of 1q (1q gain/amp) by the International Myeloma Working Group [2]. The Mayo Clinic mSMART classified t(4;14), t(14;16), t(14;20), del(17p), and gain(1q) as high-risk genetic abnormalities (accounting for approximately 40% of newly diagnosed multiple myeloma (NDMM)), and those with any two of these high-risk factors were defined as double-hit myeloma and three or more high-risk factors as triple-hit myeloma [3]. More recently, patients harboring two or more high-risk biomarkers such as t(4;14)/t(14;16)/t(14;20), del(1p), gain(1q), del(17p), and/or SKY92 gene expression risk signature were considered ultra-high-risk (UHiR) MM with very poor survival outcomes [4]. Early identification of these patients to optimize their first-line treatment is particularly important. It has been reported that single-hit patients account for 15%–25% of patients and double-hit patients account for 3%–4% [5, 6], with the most common combination being t(4;14) with 1q gain which accounts for about 50% of double/strike-hit MM [5]. The triple-hit patients with coexistence of two IGH translocations are extremely rare. Here we report the first case of a triple-hit UHiR multiple myeloma with 1q21 gain accompanied by t(4;14) and t(14;20). A 53-year-old female patient, with no history of serious illness, presented to the local hospital complaining of sleep disorder in October 2021. The laboratory evaluation revealed a significantly elevated creatinine (serum creatinine (sCr) 568 μmol/L), severe anemia (Hb 53 g/L). The patient did not receive any treatment and referred to our center 2 months later for further diagnosis and treatment. Her complete blood count was as follows: WBC 7.89 × 109/L, Hb 45 g/L, platelets 173 × 109/L. The peripheral blood smear showed 3.0% plasma cells. The humoral immunoassay showed a notable elevation in immunoglobulin IgG (43.62 g/L). Both serum and urine immunofixation electrophoresis (IFE) indicated the presence of IgG-lambda M protein and lambda light chains. Serum protein electrophoresis (SPE) showed 46.8% M protein (44.928 g/L). Serum kappa free light chain (FLC) was 33.9 mg/L (normal range 3.3–19.4 mg/L), lambda FLC was 16 150 mg/L (normal range 5.71–26.3 mg/L), ratio 0.0021 (normal range 0.26–1.65). Urinary kappa FLC was 57.8 mg/L (normal range 0.39–15.10 mg/L), lambda FLC was 7750 mg/L (normal range 0.81–10.1 mg/L), ratio 0.0075 (normal range 0.46–4.00). Renal function showed sCr 777.1 μmol/L. Serum beta 2 microglobulin was 34.3 mg/L. Serum calcium level was normal. Biochemical tests showed an elevated lactate dehydrogenase (LDH) of 310 μ/L, an increased globulin of 66 g/L, and a decreased albumin of 30 g/L. NT-proBNP was markedly elevated at 24 600 ng/L. Echocardiography showed left ventricular diastolic dysfunction with pericardial effusion. A low-dose whole-body computer tomography scan suggested generalized multiple bone destruction with osteoporosis of some bone structures, which is consistent with the imaging findings of MM. Bone marrow aspiration revealed 28% plasma cells and biopsy suggested a massive tumor plasma cell infiltration with a plasma cell percentage of 60%. Flow cytometry confirmed clonal plasma cells (CD38+, CD138+, CD45−, CD56+, CD19−, CD27−, CD117−, CD81−, kappa−, lambda+). In addition, the immunohistochemical phenotype analysis was positive for MUM1, Ki-67 (20%), BCL2, c-MYC (Minor+), and negative for LCA, CyclinD1, and CD20. Fluorescence in situ hybridization (FISH) analysis of CD138-sorted BM cells showed that 83% of plasma cells were positive for del(13q14), 81% for gain(1q21) (three copies), 85% for t(4;14), and 78% for t(14;20) (Figure 1A,B), and negative for del(17p/TP53). FISH analysis using FGFR3::IGH and MAFB::IGH dual-color dual-fusion probes revealed one yellow (der(14)t(4;14)), three green (der(4)t(4;14)del(4p16), another split IGH gene), and one red signals (normal FGFR3 gene) (1Y3G1R), and two yellow (der(14)t(14;20), der(20)t(14;20)), two green (another split IGH gene), and one red (normal MAFB gene) signals (2Y2G1R), respectively, demonstrating a break of both IGH genes. To further clarify the t(4;14) to be coexisting with t(14;20) in one clone, FISH analysis using mixed probes targeting FGFR3::IGH and MAFB::IGH was performed on the patient's sample. Six separate signals including three yellow signals (der(14)t(4;14), der(14)t(14;20), der(20)t(14;20)), one green signal (der(4)t(4;14)del(4p16)), and two red signals (normal FGFR3 and MAFB) (3Y1G2R) were observed, suggesting the coincidence of FGFR3::IGH and MAFB::IGH (Figure 1C). Meanwhile, high-resolution single nucleotide polymorphism microarray analysis (SNP-array) using Cytoscan 750K revealed a hypodiploid karyotype: 44, X, −X, dup(1)(q21q24), dup(1)(q24q32), dup(1)(q32q44), del(4)(p16.3), del(6)(q12q14), del(11)(q14q21), −13 (Figure 1D). Overall, the diagnosis of UHiR MM (IgG-λ+λ, DS IIIB, ISS III, R-ISS III) was confirmed. The patient received four courses of induction therapy with VRD (bortezomib, lenalidomide, dexamethasone) and achieved complete remission (CR). She then underwent autologous hematopoietic stem cell transplantation (ASCT) followed by four courses of consolidation therapy with IRD (ixazomib, lenalidomide, dexamethasone) and then IR for maintenance till date. Upon regular follow-up, the patient's condition is stable. The complete course of treatment is shown in Figure 1E. Risk assessment in NDMM is a critical determinant in guiding treatment. High-risk populations, especially UHiR populations, tent to exhibit an aggressive presentation, early relapse, and a poor prognosis [5, 7]. Early identification of these patients to optimize their first-line treatment regimen is particularly important. It is well known that t(4;14), t(14;20), and 1q21 gain/amp account for approximately 15%, 2%, and 40% of multiple myeloma patients, respectively [8]. Singh et al. retrospectively analyzed 55 double/triple-hit myeloma (DH/THM) and identified that the most common double-hit cytogenetic combination was t(4;14) with 1q21 gain/amp (50.9%), followed by TP53 deletion with 1q21 gain/amp (20%) and triple-hit including t(4;14) or t(14;16) with both 1q21 gain/amp and TP53 deletion (10.9% and 5.5%, respectively) [5]. In addition, the triple-hit myeloma of TP53 deletion, t(4;14) accompanied by t(14;16) or t(14;20) have been observed in another center, with one case for each combination [6]. In this report, we present a rare case of a triple-hit UHiR MM patient, characterized by the presence of t(4;14)/FGFR3::IGH, t(14;20)/MAFB::IGH, and 1q21 gain which has yet to be documented. The FISH analysis revealed 3Y1G2R signal in the context of simultaneous processing with mixed probes targeting FGFR3::IGH and MAFB::IGH (Figure 1C), suggesting that t(4;14) and t(14;20) occurred in the same clone, and that IGH on both chromosome 14 were broken and rearranged with FGFR3 and MAFB, respectively. The IGH rearrangement with MAFB results in 2Y2G1R signal as shown in Figure 1B. However, the simultaneous occurrence of 4p16 deletion (as indicated by the SNP-array result), specifically FGFR3 deletion, results in the der(4)t(4;14) signal appearing green. This is consistent with the 1Y3G1R signal formed by the FGFR3 and IGH probes (Figure 1A). Unfortunately, we cannot ascertain from the available data which rearrangement occurred at first and which occurred later. It has been reported that the accumulation of adverse chromosomal aberrations is associated with a worse outcome [9]. Among the recognized adverse factors, t(4;14)/FGFR3::IGH was identified as an independent predictor of outcome. Similarly, t(14;20) was considered an adverse factor of equal prognostic significance to t(14;16) [10]. However, the prognostic value of 1q21 gain or amplification remains controversial. Hao et al. have demonstrated that the adverse prognosis associated with 1q21 gain/amp depends on the background karyotype and TP53 status of patients. Moreover, ASCT could significantly improve outcomes in patients with double-strike and triple-strike MM containing 1q21 gain/amp [11]. In this case, the SNP-array identified a total of eight acquired chromosomal abnormalities on six chromosomes, seven of which were ﹥ 5 Mb in size, resulting in a hypodiploid karyotype. The analysis using the Chromosome Analysis Suite (ChAS) revealed that the proportions of individual chromosomal copy number variant (CNV) clones varied by more than 30% from each other, indicating the presence of subclones, which has been reported as a potential trigger of drug resistance and tumor progression [12]. The presented data highlight the genomic instability and complex background karyotype of this patient, further supporting the poor prognosis. Hence, ASCT is highly recommended to improve the patient's outcome. A significant reduction in overall survival has been confirmed in double-hit patients in comparison with single-hit and low-risk patients [5-7]. Consequently, management strategies for UHiR MM are being explored. A multicenter Phase II trial clinical study suggests that treatment with daratumumab, low-dose cyclophosphamide, lenalidomide, bortezomib, and dexamethasone (Dara-CVRd) before and after ASCT may improve the outcome of UHiR NDMM [7]. Given the markedly elevated creatinine and NT-proBNP levels at diagnosis, suggesting a combination of severe cardiac and renal insufficiency, our patient received the standard VRD induction therapy. Fortunately and surprisingly, she achieved CR after four courses of VRD and then underwent ASCT in a short period followed by extended post-ASCT IRD consolidation and IR maintenance. The patient has had a surprisingly promising outcome to this point given the underlying genetic risk factors. In conclusion, this case illustrates mainly two points: (1) Multiple myeloma with two high-risk IGH rearrangements is rare, and patients usually have complex karyotypes. (2) Currently, various guidelines still focus on FISH testing. However, SNP-array is also a very powerful approach, providing patients with a comprehensive cytogenetic background. All authors contributed to the study conception and design. J.L., Q.W., and J.W. contributed equally to this work. J.L. wrote the manuscript and analyzed the data. Q.W., Z.Z., and D.L. collected and analyzed the data. J.W., X.S., L.Y., and C.F. managed the patient treatment throughout the process. S.C., C.F., and J.P. supervised the study. All authors approved the submitted version of the paper. We thank the patient for allowing us to report this case and acknowledge the support of nurses and laboratory scientists who had participated in the process of diagnosis and treatment. The authors have nothing to report. Informed consent was obtained from the patient for the publication of any potentially identifiable images or data included in this article. The authors declare no conflicts of interest. The original contributions presented in the study are included in the article. Further inquiries can be directed to the corresponding author.