Balanced Translocations Disrupting SMARCB1 Are Hallmark Recurrent Genetic Alterations in Renal Medullary Carcinomas

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• 作者：Julien Calderaro^a ; ^b ; ^c ; ^&dagger ; ; ^{juliencalderaro@yahoo.fr" class="auth_mail" title="E-mail the corresponding author} ; Julien Masliah-Planchon^d ; ^e ; ^&dagger ; ; Wilfrid Richer^e ; ^f ; ^&dagger ; ; Laetitia Maillot^d ; Pascale Maille^a ; Ludovic Mansuy^g ; Claire Bastien^h ; Alexandre de la Taille^b ; ^c ; ⁱ ; Hé ; lè ; ne Boussion^j ; Cé ; cile Charpy^a ; Anne Jourdain^k ; Claire Blé ; chet^l ; Gaelle Pierron^d ; David Gentien^m ; Laurence Choudatⁿ ; Christophe Tournigand^c ; ^j ; Olivier Delattre^d ; ^e ; Yves Allory^a ; ^b ; ^c ; ^&Dagger ; ; Franck Bourdeaut^e ; ^f ; ^o ; ^&Dagger ;
• 关键词：Sickle cell disease ; Renal medullary carcinoma ; SMARCB1 ; Translocation
• 刊名：European Urology
• 出版年：2016
• 出版时间：June 2016
• 年：2016
• 卷：69
• 期：6
• 页码：1055-1061
• 全文大小：2111 K

文摘

Renal medullary carcinoma (RMC) is a rare and highly aggressive neoplasm that most often occurs in the setting of sickle cell trait or sickle cell disease (SCD). Most patients present with metastatic disease resistant to conventional chemotherapy, and therefore there is an urgent need for molecular insight to propose new therapies.

Objective

To determine the molecular alterations and oncogenic pathways that drive RMC development.

Design, setting, and participants

A series of five frozen samples of patients with RMC was investigated by means of gene expression profiling, array comparative genomic hybridization, and RNA and whole exome sequencing (WES).

Outcome measurements and statistical analysis

RNA and DNA sequencing read data were analyzed to detect gene fusions and somatic mutations. Gene fusions mutations were validated by real-time polymerase chain reaction and fluorescence in situ hybridization. Gene expression profiling was analyzed by unsupervised hierarchical clustering and Gene Set Enrichment Analysis (Broad Institute, Cambridge, MA, USA).

Results and limitations

We observed inactivation of the tumor suppressor gene SMARCB1 in all tumors. In all four cases developed in patients with SCD, we identified an original mechanism of interchromosomal balanced translocations that disrupt the SMARCB1 sequence and thus contribute to its inactivation. Gene expression profiling revealed that RMC shares common oncogenic pathways with pediatric malignant rhabdoid tumors, another tumor subtype characterized by SMARCB1 deficiency.

Conclusions

RMCs are characterized by an original mechanism of interchromosomal balanced translocations that disrupt the SMARCB1 sequence. WES reveals that RMCs show no other recurrent genetic alteration and an overall stable genome, underscoring the oncogenic potency of SMARCB1 inactivation.

Patient summary

Our comprehensive molecular study supports a pivotal role of the tumor suppressor gene SMARCB1 in the development of renal medullary carcinoma. The use of therapeutic strategies based on the biologic effects of its inactivation should now open new perspectives for this typically lethal malignancy.