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Gross, E.* ; van Tinteren, H.* ; Li, Z.* ; Raab, S.* ; Meul, C.* ; Avril, S.* ; Laddach, N.* ; Aubele, M. ; Propping, C.* ; Gkazepis, A.* ; Schmitt, M.* ; Meindl, A.* ; Nederlof, P.M.* ; Kiechle, M.* ; Lips, E.H.*

Identification of BRCA1-like triple-negative breast cancers by quantitative multiplex-ligation-dependent probe amplification (MLPA) analysis of BRCA1-associated chromosomal regions: A validation study.

BMC Cancer 16:811 (2016)
Verlagsversion DOI
Open Access Gold
Creative Commons Lizenzvertrag
BACKGROUND: Triple-negative breast cancer (TNBC) with a BRCA1-like molecular signature has been demonstrated to remarkably respond to platinum-based chemotherapy and might be suited for a future treatment with poly(ADP-ribose)polymerase (PARP) inhibitors. In order to rapidly assess this signature we have previously developed a multiplex-ligation-dependent probe amplification (MLPA)-based assay. Here we present an independent validation of this assay to confirm its important clinical impact. METHODS: One-hundred-forty-four TNBC tumor specimens were analysed by the MLPA-based "BRCA1-like" test. Classification into BRCA1-like vs. non-BRCA1-like samples was performed by our formerly established nearest shrunken centroids classifier. Data were subsequently compared with the BRCA1-mutation/methylation status of the samples. T-lymphocyte infiltration and expression of the main target of PARP inhibitors, PARP1, were assessed on a subset of samples by immunohistochemistry. Data acquisition and interpretation was performed in a blinded manner. RESULTS: In the studied TNBC cohort, 63 out of 144 (44 %) tumors were classified into the BRCA1-like category. Among these, the MLPA test correctly predicted 15 out of 18 (83 %) samples with a pathogenic BRCA1-mutation and 20 of 22 (91 %) samples exhibiting BRCA1-promoter methylation. Five false-negative samples were observed. We identified high lymphocyte infiltration as one possible basis for misclassification. However, two falsely classified BRCA1-mutated tumors were also characterized by rather non-BRCA1-associated histopathological features such as borderline ER expression. The BRCA1-like vs. non-BRCA1-like signature was specifically enriched in high-grade (G3) cancers (90 % vs. 58 %, p = 0.0004) and was also frequent in tumors with strong (3+) nuclear PARP1 expression (37 % vs. 16 %; p = 0.087). CONCLUSIONS: This validation study confirmed the good performance of the initial MLPA assay which might thus serve as a valuable tool to select patients for platinum-based chemotherapy regimens. Moreover, frequent PARP1 upregulation in BRCA1-like tumors may also point to susceptibility to treatment with PARP inhibitors. Limitations are the requirement of high tumor content and high-quality DNA.
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Publikationstyp Artikel: Journalartikel
Dokumenttyp Wissenschaftlicher Artikel
Schlagwörter Brca1 ; Brcaness ; Dna Repair ; Mlpa Assay ; Parp1 ; Triple-negative Breast Cancer; Homologous Recombination Deficiency; Long-term Survival; Sporadic Breast; Copy Number; Poly(adp-ribose) Polymerase; Neoadjuvant Chemotherapy; Promoter Methylation; Genomic Instability; Ovarian Cancers; Parp Inhibitors
ISSN (print) / ISBN 1471-2407
e-ISSN 1471-2407
Zeitschrift BMC Cancer
Quellenangaben Band: 16, Heft: , Seiten: , Artikelnummer: 811 Supplement: ,
Verlag BioMed Central
Verlagsort London
Begutachtungsstatus Peer reviewed