Whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes.

<h4>Background</h4>Intratumoral heterogeneity may help drive resistance to targeted therapies in cancer. In breast cancer, the presence of nodal metastases is a key indicator of poorer overall survival. The aim of this study was to identify somatic genetic alterations in early disseminat...

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Main Authors: Kevin Blighe, Laura Kenny, Naina Patel, David S Guttery, Karen Page, Julian H Gronau, Cyrus Golshani, Justin Stebbing, R Charles Coombes, Jacqueline A Shaw
Format: Article
Language:English
Published: Public Library of Science (PLoS) 2014-01-01
Series:PLoS ONE
Online Access:https://doi.org/10.1371/journal.pone.0115346
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author Kevin Blighe
Laura Kenny
Naina Patel
David S Guttery
Karen Page
Julian H Gronau
Cyrus Golshani
Justin Stebbing
R Charles Coombes
Jacqueline A Shaw
author_facet Kevin Blighe
Laura Kenny
Naina Patel
David S Guttery
Karen Page
Julian H Gronau
Cyrus Golshani
Justin Stebbing
R Charles Coombes
Jacqueline A Shaw
author_sort Kevin Blighe
collection DOAJ
description <h4>Background</h4>Intratumoral heterogeneity may help drive resistance to targeted therapies in cancer. In breast cancer, the presence of nodal metastases is a key indicator of poorer overall survival. The aim of this study was to identify somatic genetic alterations in early dissemination of breast cancer by whole genome next generation sequencing (NGS) of a primary breast tumor, a matched locally-involved axillary lymph node and healthy normal DNA from blood.<h4>Methods</h4>Whole genome NGS was performed on 12 µg (range 11.1-13.3 µg) of DNA isolated from fresh-frozen primary breast tumor, axillary lymph node and peripheral blood following the DNA nanoball sequencing protocol. Single nucleotide variants, insertions, deletions, and substitutions were identified through a bioinformatic pipeline and compared to CIN25, a key set of genes associated with tumor metastasis.<h4>Results</h4>Whole genome sequencing revealed overlapping variants between the tumor and node, but also variants that were unique to each. Novel mutations unique to the node included those found in two CIN25 targets, TGIF2 and CCNB2, which are related to transcription cyclin activity and chromosomal stability, respectively, and a unique frameshift in PDS5B, which is required for accurate sister chromatid segregation during cell division. We also identified dominant clonal variants that progressed from tumor to node, including SNVs in TP53 and ARAP3, which mediates rearrangements to the cytoskeleton and cell shape, and an insertion in TOP2A, the expression of which is significantly associated with tumor proliferation and can segregate breast cancers by outcome.<h4>Conclusion</h4>This case study provides preliminary evidence that primary tumor and early nodal metastasis have largely overlapping somatic genetic alterations. There were very few mutations unique to the involved node. However, significant conclusions regarding early dissemination needs analysis of a larger number of patient samples.
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spelling doaj-art-359cd41639f74ebf893bed745b8607f02025-08-20T02:22:39ZengPublic Library of Science (PLoS)PLoS ONE1932-62032014-01-01912e11534610.1371/journal.pone.0115346Whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes.Kevin BligheLaura KennyNaina PatelDavid S GutteryKaren PageJulian H GronauCyrus GolshaniJustin StebbingR Charles CoombesJacqueline A Shaw<h4>Background</h4>Intratumoral heterogeneity may help drive resistance to targeted therapies in cancer. In breast cancer, the presence of nodal metastases is a key indicator of poorer overall survival. The aim of this study was to identify somatic genetic alterations in early dissemination of breast cancer by whole genome next generation sequencing (NGS) of a primary breast tumor, a matched locally-involved axillary lymph node and healthy normal DNA from blood.<h4>Methods</h4>Whole genome NGS was performed on 12 µg (range 11.1-13.3 µg) of DNA isolated from fresh-frozen primary breast tumor, axillary lymph node and peripheral blood following the DNA nanoball sequencing protocol. Single nucleotide variants, insertions, deletions, and substitutions were identified through a bioinformatic pipeline and compared to CIN25, a key set of genes associated with tumor metastasis.<h4>Results</h4>Whole genome sequencing revealed overlapping variants between the tumor and node, but also variants that were unique to each. Novel mutations unique to the node included those found in two CIN25 targets, TGIF2 and CCNB2, which are related to transcription cyclin activity and chromosomal stability, respectively, and a unique frameshift in PDS5B, which is required for accurate sister chromatid segregation during cell division. We also identified dominant clonal variants that progressed from tumor to node, including SNVs in TP53 and ARAP3, which mediates rearrangements to the cytoskeleton and cell shape, and an insertion in TOP2A, the expression of which is significantly associated with tumor proliferation and can segregate breast cancers by outcome.<h4>Conclusion</h4>This case study provides preliminary evidence that primary tumor and early nodal metastasis have largely overlapping somatic genetic alterations. There were very few mutations unique to the involved node. However, significant conclusions regarding early dissemination needs analysis of a larger number of patient samples.https://doi.org/10.1371/journal.pone.0115346
spellingShingle Kevin Blighe
Laura Kenny
Naina Patel
David S Guttery
Karen Page
Julian H Gronau
Cyrus Golshani
Justin Stebbing
R Charles Coombes
Jacqueline A Shaw
Whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes.
PLoS ONE
title Whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes.
title_full Whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes.
title_fullStr Whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes.
title_full_unstemmed Whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes.
title_short Whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes.
title_sort whole genome sequence analysis suggests intratumoral heterogeneity in dissemination of breast cancer to lymph nodes
url https://doi.org/10.1371/journal.pone.0115346
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