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J Pathol. 2012 May;227(1):42-52. doi: 10.1002/path.3990. Epub 2012 Mar 21.

Genomic and mutational profiling of ductal carcinomas in situ and matched adjacent invasive breast cancers reveals intra-tumour genetic heterogeneity and clonal selection.

Author information

1
Molecular Pathology Team, The Breakthrough Breast Cancer Research Centre, The Institute of Cancer Research, London SW3 6JB, UK.
2
Department of Anatomic Pathology, Hospital Universitario 12 de Octubre, Madrid, Spain.
3
Department of Tumour Biology, Institut Curie, 75005 Paris, France.
4
Cancer Research UK Clinical Trials Unit, The Institute of Cancer Research, Sutton SM2 5NG, UK.
5
Department of Biomedical Sciences and Human Oncology, University of Turin, Turin, Italy.
6
Hospital Universitario Virgen del Rocio, Seville, Spain.
7
Signal Transduction Laboratory, Cancer Research UK London Research Institute, London WC2A 3LY, UK.
#
Contributed equally

Abstract

The mechanisms underlying the progression from ductal carcinoma in situ (DCIS) to invasive ductal carcinoma (IDC) of the breast are yet to be fully elucidated. Several hypotheses have been put forward to explain the progression from DCIS to IDC, including the selection of a subpopulation of cancer cells with specific genetic aberrations, and the acquisition of new genetic aberrations or non-genetic mechanisms mediated by the tumour microenvironment. To determine whether synchronously diagnosed ipsilateral DCI and IDCs have modal populations with distinct repertoires of gene copy number aberrations and mutations in common oncogenes, matched frozen samples of DCIS and IDC were retrieved from 13 patients and subjected to microarray-based comparative genomic hybridization (aCGH) and Sequenom MassARRAY (Oncocarta v 1.0 panel). Fluorescence in situ hybridization and Sanger sequencing were employed to validate the aCGH and Sequenom findings, respectively. Although the genomic profiles of matched DCI and IDCs were similar, in three of 13 matched pairs amplification of distinct loci (ie 1q41, 2q24.2, 6q22.31, 7q11.21, 8q21.2 and 9p13.3) was either restricted to, or more prevalent in, the modal population of cancer cells of one of the components. Sequenom MassARRAY identified PIK3CA mutations restricted to the DCIS component in two cases, and in a third case the frequency of the PIK3CA mutant allele reduced from 49% in the DCIS to 25% in the IDC component. Despite the genomic similarities between synchronous DCIS and IDC, our data provide strong circumstantial evidence to suggest that in some cases the progression from DCIS to IDC is driven by the selection of non-modal clones that harbour a specific repertoire of genetic aberrations.

PMID:
22252965
PMCID:
PMC4975517
DOI:
10.1002/path.3990
[Indexed for MEDLINE]
Free PMC Article

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