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Whole-genome profiling helps to classify phyllodes tumours of the breast
  1. Marick Laé1,
  2. Philippe La Rosa2,3,4,5,
  3. Jonas Mandel2,3,4,5,
  4. Fabien Reyal6,
  5. Philippe Hupé2,3,4,5,7,
  6. Philippe Terrier8,
  7. Jérôme Couturier9
  1. 1Service de Pathologie, Institut Curie, PSL Research University, Paris, France
  2. 2Institut Curie, Paris, France
  3. 3PSL Research University, Paris, France
  4. 4Inserm, U900, Paris, France
  5. 5Mines Paris Tech, Fontainebleau, France
  6. 6Service de chirurgie et SIRIC, Institut Curie, PSL Research University, Paris, France
  7. 7CNRS, UMR 144, Paris, France
  8. 8Service de Pathologie, Institut Gustave Roussy, Villejuif, France
  9. 9Service de Génétique, Institut Curie, PSL Research University, Paris, France
  1. Correspondence to Dr Marick Laé, Service de Pathologie, Institut Curie, 26 rue d'Ulm, Paris F-75248 Cedex, France; marick.lae{at}curie.fr

Abstract

Aims The aim of this study was to analyse a series of borderline and malignant phyllodes tumours (PTs) of the breast by whole-genome profiling to identify genomic markers that could help to recognise potentially malignant tumours within borderline tumours.

Methods We evaluated the genetic imbalances of a series of 53 PTs (30 borderline, 23 malignant) using the Human CNV370 BeadChip microarray (Illumina), containing 370 000 SNP markers and correlate this alterations with clinicopathological features.

Results Forty-five PTs (85%) showed chromosome copy number variations (CNVs). Twenty PTs (37%) showed five or more chromosomal imbalances (8/30 borderline (27%) and 12/23 malignant (52%)). The large-scale genetic changes associated with malignant were+7p (9/23), +1q (8/23), −10p (8/23), −13q14 (7/23), +8q (6/23) and +10q (6/23) and borderline were+1q (13/30), −13q14 (9/30), −6q (8/30) and −10p (8/30). Losses in 9p21.3, encompassing CDKN2A/B gene, were present in three tumours (malignant), whereas deletions of 13q, with a minimal region in 13q14.2 encompassing the RB1 gene, were found in 9/30 borderline and 7/28 malignant tumours. High-level amplifications were seen in eight tumours (seven malignant and one borderline): in 7p in three tumours (including EGFR in two), 7q31.2 (including TFEC and MET), 8q24.21 (including MYC) and 8q23.3 (including CSMD3) in one tumour each.

Conclusions Whole-genome profiling by SNP arrays in PTs leads to identify a high number of CNV, gains of 7p and 8q, losses of 13q and 10, losses in 9p21.3 (CDKN2A/B) and the presence of amplifications, especially involving EGFR, as markers of potentially malignant tumours.

  • BREAST PATHOLOGY
  • MOLECULAR PATHOLOGY
  • CYTOGENETICS

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Footnotes

  • This work has been presented at the 2015 American and Canadian Academy of Pathology (abstract, Laboratory Investigation (2015) 95, 30–75).

  • Handling editor Runjan Chetty

  • Contributors All contributors participated in the study and approved manuscript.

  • Funding CONTICANET.

  • Competing interests None declared.

  • Patient consent Obtained.

  • Ethics approval Breast Cancer Study Group of Institut Curie.

  • Provenance and peer review Not commissioned; externally peer reviewed.

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