MYC amplification in angiosarcoma depends on etiological/clinical subgroups – Diagnostic and prognostic value

Angiosarcomas (AS) are rare and heterogeneous malignant vascular tumors with a dismal prognosis. We undertook a retrospective study of AS cases with the intent of elucidating the prevalence of MYC amplification amongst different etiological/clinical subgroups and identifying MYC's potential as a prognostic biomarker.Retrospective collection of data and tumor samples from 110 patients diagnosed with AS in the Netherlands was conducted. Histopathological review and investigation of MYC gene amplification and MYC protein overexpression (using fluorescent in situ hybridization and immunohistochemistry, respectively) was performed.MYC amplification was identified in 50.9 % of cases and predominantly present in secondary AS (sAS) (especially radiotherapy-associated and Stewart-Treves AS, both 92.9 %). Within the primary AS (pAS) subgroup, skin non-UV-associated AS (69.2 %) and primary breast AS (29.4 %) demonstrated MYC amplification. MYC protein overexpression was observed in 47.7 % of all tumors with an overall sensitivity and specificity of 75 % and 81 % respectively. There was no significant difference in median overall survival (OS) between patients with MYC and non-MYC amplified AS. Patients with AS displaying MYC protein overexpression had significantly shorter OS than those without (p = 0.028).Although MYC amplification is characteristic for secondary radiotherapy-associated and Stewart-Treves AS, it is not exclusive to these groups and can also be found in a subset of pAS. Overall concordance of FISH and IHC is rather poor. Only primary breast AS showed 100 % concordance. Therefore MYC expression as surrogate marker should be used with caution. The role of MYC/MYC as a prognostic indicator is undefined, however resulting tailored treatment options could be considered.     

Characterization of trisomy 8 in pediatric undifferentiated sarcomas using advanced molecular cytogenetic techniques

Pediatric undifferentiated soft tissue sarcomas (USTS) are a rare group of neoplasms that are unclassifiable despite the application of immunohistochemical, cytogenetic, and molecular techniques. To date, there is a dearth of studies looking at the cytogenetic and molecular genetic alterations in such tumors. Trisomy 8, a frequent molecular alteration in neoplasia, is seen in several soft tissue sarcomas, including Ewing sarcoma/primitive neuroectodermal tumor (ES/PNET), synovial sarcoma, and leiomyosarcoma. Because USTS share several clinicobiological features with the aforementioned tumors, the occurrence of alterations in chromosome 8 was studied in 11 pediatric USTS using a combination of interphase fluorescence in situ hybridization (FISH), spectral karyotyping (SKY), and genomic profiling with oligonucleotide array comparative genomic hybridization (aCGH). The copy number status of MYC was also assessed on the same tumors using dual-color FISH, with the aim of delineating the degree and intratumoral distribution of MYC amplification in this tumor. A near-uniform presence of an increase in MYC copy number was observed, along with an increase in chromosome 8 copy number in all the tumors. SKY and aCGH analysis of tumors exhibiting trisomy 8 confirmed the numerical imbalances. The occurrence of trisomy 8 in a subset of pediatric USTS confirms a shared genomic alteration with several other soft tissue sarcomas. Further studies are required to determine the clinical implications of such a finding.     

MYC amplification and TERT expression in breast tumor progression

The complex roles of genomic instability, MYC oncogene amplification, activation of telomerase, and p53 function still remain to be fully described in breast tumors. MYC stimulates the telomerase catalytic subunit, TERT, which interacts with p53. Oncogene MYC amplification analysis was performed on 27 paraffin-embedded breast tumor samples by fluorescence in situ hybridization, selected on the basis of chromosomal instability. TERT immunostaining was performed on a larger group of breast tumor sections. All tumor samples were analyzed for TP53 mutation, genomic index, S-phase fraction, and pathological stages. Amplification of MYC was detected in 16 of 27 tumors (59%) and found to be associated with TNM stages I and II (P = 0.018), genomic index > 1.5 (P = 0.033), and S-phase fraction > 5% (P = 0.020). No association was found between MYC amplification and TERT immunostaining or TP53 mutations. Analysis of TERT in 103 primary breast tumors showed > 50% nuclei immunostaining in 58% of cases. High TERT immunostaining associated with genomic index > 1.5 (P = 0.017), high S-phase fraction (P = 0.056), and TP53 mutations (P = 0.030). No association was found between TERT staining and TNM stages. This study supports early involvement of MYC amplification in breast tumor progression. Both MYC amplification and TERT expression appear to be associated with high genomic instability and proliferation. TERT association with TP53 mutations indicates that TERT activity is downregulated by functional p53 protein in breast tumors.     

MicroRNA与淋巴增殖性疾病

在动植物基因组中广泛存在一类非编码蛋白的小RNA,即microRNA（miRNA）。miRNA在肿瘤的形成和转录后调节基因表达中起重要作用。miR-15a和miR-16-1表达水平的改变与慢性淋巴细胞白血病（CLL）有关,原癌基因bcl-2可能是miR-15a和miR-16-1的靶基因;活化B细胞型弥漫性大B细胞淋巴瘤（DLBCL）、儿童Burkitt淋巴瘤等肿瘤细胞miR-155的拷贝数明显增高,认为miR-155表达水平可以作为DLBCL诊断和预后的重要指标;miR-17-92簇（miR-15a, miR-16-1, miR-155, miR-17-92 cluster, miR-142）是一组可能的肿瘤相关基因。     

MiR-17-92 cluster is a novel regulatory gene of cardiac ischemic/reperfusion injury

The miR-17-92 cluster is an important microRNA cluster in the animals. It was mainly investigated as an oncogene in tumors but never studied in cardiovascular disease. On one aspect, miR-17-92 cluster is documented to play anti-apoptotic roles in tumor cells, including hypoxia-induced apoptosis. The families of miR-17, miR-19, and miR-92 promote resistance to apoptosis by directly inhibiting pro-apoptotic protein, and by the two major cell survival signaling pathways—PI3K/AKT, and MAPK/ERK. On the other aspect, the component members of miR-17-92 cluster are high expressed in the hearts of canine and mice, suggesting that there are effect targets of the cluster in the myocardium. So that, we hypothesized that the miR-17-92 cluster may protect the heart by diminishing the apoptosis and alleviating ischemia/reperfusion injury. This may be a new regulating target for patients with myocardial infarction and undergoing cardiac surgery.     

Lymphoproliferative disease and autoimmunity in mice with increased miR-17-92 expression in lymphocytes

The genomic region encoding the miR-17-92 microRNA (miRNA) cluster is often amplified in lymphoma and other cancers, and cancer cells carrying this amplification have higher expression of miRNA in this cluster. Retroviral expression of miR-17-92 accelerates c-Myc-induced lymphoma development, but precisely how higher expression of miR-17-92 promotes lymphomagenesis remains unclear. Here we generated mice with higher expression of miR-17-92 in lymphocytes. These mice developed lymphoproliferative disease and autoimmunity and died prematurely. Lymphocytes from these mice showed more proliferation and less activation-induced cell death. The miR-17-92 miRNA suppressed expression of the tumor suppressor PTEN and the proapoptotic protein Bim. This mechanism probably contributed to the lymphoproliferative disease and autoimmunity of miR-17-92-transgenic mice and contributes to lymphoma development in patients with amplifications of the miR-17-92 coding region.     

Amplification of EIF3S3 Gene Is Associated with Advanced Stage in Prostate Cancer

Gain of the long arm of chromosome 8 (8q) is one of the most common gains found in the advanced prostate cancer by comparative genomic hybridization. We have previously identified a putative target gene for the 8q gain, EIF3S3, that encodes a p40 subunit of eukaryotic translation initiation factor 3 (eIF3). Here, we studied the frequency of the EIF3S3 amplification in different stages of prostate cancer and co-amplification of EIF3S3 and oncogene MYC. In addition, prognostic utility of the EIF3S3 copy number alteration was evaluated. The analyses were done with fluorescence in situ hybridization and tissue microarray technology. High-level amplification of EIF3S3 was found in 11 of 125 (9%) of pT1/pT2 tumors, 12 of 44 (27%) of pT3/pT4 tumors, and 8 of 37 (22%) of lymph node metastases as well as in 26 of 78 (33%) and 15 of 30 (50%) of hormone refractory locally recurrent tumors and metastases, respectively. The amplification was associated with high Gleason score (P < 0.001). One of the 79 tumors with EIF3S3 amplification had only two copies of MYC, whereas all tumors with amplification of MYC had also amplification of EIF3S3 indicating common co-amplification of the genes. Gain of EIF3S3 was associated with poor cancer-specific survival in incidentally found prostate carcinomas (P = 0.023). In the analyses of prostatectomy-treated patients, the amplification was not statistically significantly associated with progression-free time. In conclusion, amplification of EIF3S3 gene is common in late-stage prostate cancer suggesting that it may be functionally involved in the progression of the disease.     

Aberrant keratin expression is common in primary hepatic malignant vascular tumors: A potential diagnostic pitfall

Malignant vascular neoplasms such as epithelioid hemangioendothelioma (EHE) and angiosarcoma (AS) can arise within the liver. The aim of this study was to study the expression of keratins CK7, AE1/AE3 and OSCAR in primary hepatic EHE and AS. 9 cases of hepatic EHE and 13 cases of hepatic AS were stained with ERG, CK7, keratin AE1/AE3 and keratin OSCAR. Their expression was graded as 1+ (1–25% of tumor cells positive), 2+ (26–50%), 3+ (51–75%) or 4+ (>75%). ERG was positive in all 9 (100%) EHEs and all 13 (100%) ASs. CK7 was positive in 5/9 (56%) EHEs (2, 1+; 1, 2+; 1, 3+; 1, 4+) and 1/13 (8%) AS (2+). Keratin OSCAR was positive in 6/9 (67%) EHEs (5, 1+; 1, 2+) and 4/13 (31%) ASs (2, 1+; 1, 2+; 1, 4+). Keratin AE1/AE3 was positive in 6/9 (67%) EHEs (3, 1+; 3; 2+) and 4/13 (31%) ASs (2, 1+; 1, 2+; 1, 4+). Overall, 6/ 9 (67%) EHEs were positive for at least one keratin marker, of which 5 were positive for all 3 keratins (AE1/AE3, OSCAR and CK7) while 1 was positive only for 2 keratins (OSCAR and AE1/AE3). 4/13 (31%) of ASs were positive for both keratins OSCAR and AE1/AE3, of which 1 case was also positive for CK7. Aberrant keratin expression is common in primary hepatic EHEs (67%) and ASs (31%). Awareness of this diagnostic pitfall is important for avoiding misdiagnosis of these primary hepatic malignant vascular tumors as carcinomas.     

Trisomy 4 and double minutes in acute myeloid leukemia: further evidence that double minutes can occur as the primary cytogenetic abnormality

The specific association of trisomy 4 and double minutes (dmin) is rare and is usually reported in patients with acute myeloid leukemia (AML), primarily M2 and M4 subtypes. Several previous reports describing this combination suggested that trisomy 4 was the primary cytogenetic abnormality, and that the presence of the dmin was secondary. We describe a 79-year-old male who presented with myelodysplasia, transforming to AML-M2. Cytogenetic analysis of bone marrow aspirate cultures showed a 46,XY,dmin[12]/47,XY,+4,dmin[7]/46, XY[6] karyotype. The number of dmin ranged from 1 to 150. Fluorescence in situ hybridization (FISH) analysis showed that the dmin were derived from amplification of the MYC oncogene. Dual-color interphase FISH analysis was performed with D4Z1 and MYC probes and showed no evidence of a clone containing trisomy 4 without dmin. These data suggest that dmin may also occur as the primary cytogenetic abnormality in patients with trisomy 4 and dmin.     

Combined array comparative genomic hybridization and tissue microarray analysis suggest PAK1 at 11q13.5-q14 as a critical oncogene target in ovarian carcinoma

Amplification of chromosomal regions leads to an increase of DNA copy numbers and expression of oncogenes in many human tumors. The identification of tumor-specific oncogene targets has potential diagnostic and therapeutic implications. To identify distinct spectra of oncogenic alterations in ovarian carcinoma, metaphase comparative genomic hybridization (mCGH), array CGH (aCGH), and ovarian tumor tissue microarrays were used in this study. Twenty-six primary ovarian carcinomas and three ovarian carcinoma cell lines were analyzed by mCGH. Frequent chromosomal overrepresentation was observed on 2q (31%), 3q (38%), 5p (38%), 8q (52%), 11q (21%), 12p (21%), 17q (21%), and 20q (52%). The role of oncogenes residing in gained chromosomal loci was determined by aCGH with 59 genetic loci commonly amplified in human tumors. DNA copy number gains were most frequently observed for PIK3CA on 3q (66%), PAK1 on 11q (59%), KRAS2 on 12p (55%), and STK15 on 20q (55%). The 11q13-q14 amplicon, represented by six oncogenes (CCND1, FGF4, FGF3, EMS1, GARP, and PAK1) revealed preferential gene copy number gains of PAK1, which is located at 11q13.5-q14. Amplification and protein expression status of both PAK1 and CCND1 were further examined by fluorescence in situ hybridization and immunohistochemistry using a tissue microarray consisting of 268 primary ovarian tumors. PAK1 copy number gains were observed in 30% of the ovarian carcinomas and PAK1 protein was expressed in 85% of the tumors. PAK1 gains were associated with high grade (P < 0.05). In contrast, CCND1 gene alterations and protein expression were less frequent (10.6% and 25%, respectively), suggesting that the critical oncogene target of amplicon 11q13-14 lies distal to CCND1. This study demonstrates that aCGH facilitates further characterization of oncogene candidates residing in amplicons defined by mCGH.     

Genomic and immunophenotypical characterization of pure micropapillary carcinomas of the breast

Pure invasive micropapillary carcinoma (MPC) is a special histological type that accounts for 0.7-3% of all breast cancers. MPC has a distinctive growth pattern and a more aggressive clinical behaviour than invasive ductal carcinomas of no special type (IDC-NSTs). To define the molecular characteristics of MPCs, we profiled a series of 12 MPCs and 24 grade and oestrogen receptor (ER)-matched IDC-NSTs using high-resolution microarray comparative genomic hybridization (aCGH). In addition, we generated a tissue microarray containing a series of 24 MPCs and performed immunohistochemical analysis with ER, PR, Ki-67, HER2, CK5/6, CK14, CK17, EGFR, topoisomerase-IIalpha, cyclin D1, caveolin-1, E-cadherin, and beta-catenin antibodies. In situ hybridization probes were employed to evaluate the prevalence of amplification of HER2, TOP2A, EGFR, CCND1, MYC, ESR1, and FGFR1 genes. aCGH analysis demonstrated that MPCs significantly differed from IDC-NSTs at the genomic level. Gains of 1q, 2q, 4p, 6p, 6q23.2-q27, 7p, 7q, 8p, 8q, 9p, 10p, 11q, 12p, 12q, 16p, 17p, 17q, 19p, 20p, 20q, and 21q, and losses of 1p, 2p, 6q11.1-q16.3, 6q21-q22.1, 9p, 11p, 15q, and 19q were more prevalent in MPCs. High-level gains/amplifications of 8p12-p11, 8q12, 8q13, 8q21, 8q23, 8q24, 17q21, 17q23, and 20q13 were significantly associated with MPCs. A comparison between 24 MPCs and a series of 48 grade and ER-matched IDC-NSTs revealed that high cyclin D1 expression, high proliferation rates, and MYC (8q24) amplification were significantly associated with MPCs. Our results demonstrate that MPCs have distinct histological features and molecular genetic profiles supporting the contention that they constitute a distinct pathological entity.     

MYC gene amplification is often acquired in lethal distant breast cancer metastases of unamplified primary tumors

In breast cancer, amplification of MYC is consistently observed in aggressive forms of disease and correlates with poor prognosis and distant metastases. However, to date, a systematic analysis of MYC amplification in metastatic breast cancers has not been reported. Specifically, whether the MYC amplification status may change in metastases in comparison to the corresponding primary breast tumor, and potential variability among different metastases within the same patient have also not been assessed. We generated single patient tissue microarrays consisting of both primary breast carcinomas and multiple matched systemic metastases from 15 patients through our previously described rapid autopsy program. In total, the 15 tissue microarrays contained 145 primary tumor spots and 778 spots derived from 180 different metastases. In addition, two separate tissue microarrays were constructed composed of 10 matched primary breast cancers and corresponding solitary metastases sampled not at autopsy but rather in routine surgical resections. These two tissue microarrays totaled 50 primary tumor spots and 86 metastatic tumor spots. For each case, hormone receptor status, HER2/neu, EGFR and CK5/6 expression were assessed, and the cases were characterized as luminal, basal-like or HER2 based on published criteria. Both fluorescence in situ hybridization and immunohistochemistry for MYC was performed on all cases. Of the 25 cases, 24 were evaluable. While 4 of 24 primary tumors (16%) demonstrated MYC amplification, an additional 6 (25% of total evaluable cases) acquired MYC amplification in their systemic metastases. Of note, there was remarkably little heterogeneity in MYC copy number among different metastases from the same patient. MYC immunoreactivity was increased in metastases relative to matched primaries in the surgical cohort, although there was no perfect correlation with MYC amplification. In conclusion, amplification of MYC is a frequent event in breast cancer, but occurs more frequently as a diffuse, acquired event in metastatic disease than in the corresponding primary. These observations underscore the importance of MYC in breast cancer progression/metastasis, as well as its relevance as a potential therapeutic target in otherwise incurable metastatic disease.     

应用间期荧光原位杂交技术检测原发性肝细胞癌c-myc基因扩增的临床意义

目的：探讨c-myc基因在原发性肝细胞癌中的扩增及其与临床及预后的关系。方法：应用间期核荧光在位杂交技术对100例原发性肝癌和6例带卫星结节的肝癌组织标本进行检测。结果：92％（92例）原发性肝癌组织存在c-myc基因扩增,其中高拷贝数扩增达37％（37例）,低拷贝数扩增55％（55例）,只有8％（8例）,无扩增,结合临床资料分析,c-myc扩增与患者临床分期,肿瘤大小和病理类型无明显相关（P＞0．05）,原发肿瘤和相应卫星结节肿瘤组织具有相似的c-myc基因扩增水平和相同病理类型的特点,在可随诊两年半的90例病例中,91．1％（82例）病例有c-myc基因扩增,其中高拷贝数扩增34例,低拷贝数扩增48例,无扩增8例,分析c-myc扩增程度与患者术后复发的时间及生存期关系,发现c-myc高拷贝数扩增的病例术后1年内复发率（70．6％,24／34）高于c-myc低拷贝数扩增（39．6％,19／48）和无扩增者（12．5％,1／8）,三者这产差异有显著性意义（P＜0．05）,而在术后＞12个月的复发率则与c-myc不同扩增程度间差异无显著性意义（P＞05）,另外,c-myc高拷贝数扩增者术后2年存活率明显低于低拷数扩增和无扩增者（P＝0．01）,结论：原发性肝细胞癌存在高频率的C-myc基因扩增,基因扩增与患者临床分期,肿瘤大小和病理类型无明显相关性,但与患者预后有关,高拷贝数扩增者复发时间是,复发率高,生存期短。     

miR-17~92 cooperates with RB pathway mutations to promote retinoblastoma

The miR-17~92 cluster is a potent microRNA-encoding oncogene. Here, we show that miR-17~92 synergizes with loss of Rb family members to promote retinoblastoma. We observed miR-17~92 genomic amplifications in murine retinoblastoma and high expression of miR-17~92 in human retinoblastoma. While miR-17~92 was dispensable for mouse retinal development, miR-17~92 overexpression, together with deletion of Rb and p107, led to rapid emergence of retinoblastoma with frequent metastasis to the brain. miR-17~92 oncogenic function in retinoblastoma was not mediated by a miR-19/PTEN axis toward apoptosis suppression, as found in lymphoma/leukemia models. Instead, miR-17~92 increased the proliferative capacity of Rb/p107-deficient retinal cells. We found that deletion of Rb family members led to compensatory up-regulation of the cyclin-dependent kinase inhibitor p21Cip1. miR-17~92 overexpression counteracted p21Cip1 up-regulation, promoted proliferation, and drove retinoblastoma formation. These results demonstrate that the oncogenic determinants of miR-17~92 are context-specific and provide new insights into miR-17~92 function as an RB-collaborating gene in cancer.     

Postradiation cutaneous angiosarcoma after treatment of breast carcinoma is characterized by MYC amplification in contrast to atypical vascular lesions after radiotherapy and control cases: clinicopathological, immunohistochemical and molecular analysis of 66 cases

Postradiation cutaneous vascular lesions after treatment of breast carcinoma comprise a heterogeneous group of benign, atypical, and malignant lesions and are best regarded as points along a morphological spectrum. We analyzed a series of cutaneous angiosarcomas after treatment of breast cancer in comparison with control cases and cases of atypical vascular lesions with special emphasis on the expression and amplification of MYC. The 66 cases were divided into control cases (5), cases in which a slight vascular proliferation was seen after radiotherapy of breast cancer (12), cases of atypical vascular lesions after radiotherapy (16), cases of postradiation cutaneous angiosarcomas (25), and cases of angiosarcomas of skin and soft tissues unrelated to radiotherapy (8). None of the control cases (2 M, 3 F, 20-76 years), of cases showing slight vascular proliferation, dermal fibrosis and inflammation after radiotherapy of breast cancer (12 F, 48-79 years), of cases of atypical vascular lesions after radiotherapy (16 F, 29-81 years), and of cases of angiosarcomas of skin and soft tissues unrelated to radiotherapy (3 M, 5 F, 25-92 years) showed an amplification of MYC by FISH analysis. In striking contrast, in all cases of postradiation cutaneous angiosarcomas (25 F, 46-95 years), MYC amplification was found by FISH analysis in a variable number of counted nuclei. Immunohistochemically, strong positive nuclear staining for MYC and prox-1 was seen in cases of postradiation cutaneous angiosarcoma, whereas control cases and cases of atypical vascular proliferation after radiotherapy were negative for MYC, and stained only focally positive for prox-1 in a number of cases. In conclusion, the presence of MYC amplification represents an important additional diagnostic tool in the distinction of postradiation cutaneous angiosarcomas from atypical vascular lesions after radiotherapy. Immunohistochemical stainings for MYC are useful for mapping of these lesions and for careful tumor margin control.     

miR-17 and miR-20a Expression in IL-2 Signaling Pathway in Jurkat T Cells

Background: the miR-17-92 cluster is known as an oncogene (oncomiR-1) overexpressed in most cancers. However, recent studies have shown that these miRNAs were downregulated in some cancers. Thus, some or all members of miR-17-92 cluster may have dual activity: apoptosis induction or inhibition. Objectives: For a better understanding of miR-17-92 cluster activities, we focused on the function of mir-17 and mir-20a as two members of miR-17-92 cluster in Jurkat cells activated by phytohemagglutinin (PHA). Materials and Methods: Jurkat cells were stimulated by PHA for 24 h. P-lenti-mico-GFP plasmids containing miR-17 or miR-20a and an empty vector (blank) were transfected into activated Jurkat cells using Lipofectamine 2000 reagent. Cell viability was measured using XTT assay after transfection. Putative targets of these miRNAs were predicted by Targetscan and miRWalk algorithms in JAK/STAT and PI3K/AKT signaling pathways. Then the expression of several putative targets was evaluated by quantitative RT-PCR. Results: Transfection of mir-17 and mir-20a decreased the proliferation in activated Jurkat cells. In silico investigations revealed that mir-17 and mir-20a potentially target JAK1, AKT1 and AKT3. Q-RT-PCR analysis illustrated that these targets were downregulated in Jurkat cells after transfection with miR-17 and miR-20a. Conclusions: According to our findings, it seems that mir-17 and mir-20a expression, two members of miR-17-92 cluster, is dependent on cell condition and cell type; as a result, their ectopic expression in activated Jurkat cells may lead to cell death.     

Secondary genomic rearrangements involving immunoglobulin or MYC loci show similar prevalences in hyperdiploid and nonhyperdiploid myeloma tumors

The pathogenesis of multiple myeloma (MM) is thought to involve at least two pathways, which generate hyperdiploid (HRD) or nonhyperdiploid (NHRD) tumors, respectively. Apart from chromosome content, the two pathways are distinguished by five primary immunoglobulin heavy chain (IGH) rearrangements (4p16, FGFR3, and MMSET; 6p21, CCND3; 11q13, CCND1; 16q23, MAF; 20q12, MAFB) that are present mainly in NHRD tumors. To determine the prevalence and structures of IGH, immunoglobulin (IG) light chain, and MYC genomic rearrangements in MM, we have done comprehensive metaphase fluorescent in situ hybridization analyses on 48 advanced MM tumors and 47 MM cell lines. As expected, the prevalence of the five primary IGH rearrangements was nearly 70% in NHRD tumors, but only 12% in HRD tumors. However, IGH rearrangements not involving one of the five primary partners, and IG light chain rearrangements, have a similar prevalence in HRD and NHRD tumors. In addition, MYC rearrangements, which are thought to be late progression events that sometimes do not involve an IG heavy or light chain locus, also have a similar prevalence in HRD and NHRD tumors. In contrast to the primary IGH rearrangements, which usually are simple balanced translocations, these other IG rearrangements usually have complex structures, as previously described for MYC rearrangements in MM. We conclude that IG light chain and MYC rearrangements, as well as secondary IGH rearrangements, make similar contributions to the progression of both HRD and NHRD MM tumors.