Highlights
- •Targeted PTEN mutations are associated with the loss of PTEN IHC expression in breast carcinomas.
- •PTEN alterations are only associated with tumours of the basal like subgroup arising in the context of a germline BRCA1 mutation
- •Aberrant BRCA1 and PTEN expression are independent events in sporadic TN breast tumours.
Abstract
The similarities between sporadic basal-like breast cancer (BLBC) and BRCA1-mutated breast tumours raise the possibility that deregulation of the same pathway
may underlie these tumour types. The aim of this study was to determine if PTEN aberrations are characteristic of both BRCA1 tumours and sporadic TN breast carcinomas with low BRCA1 expression, and can thus be used to identify sporadic tumours potentially sensitive
to PARP inhibitors. Twelve BRCA1 tumours, 19 non-BRCA familial breast tumours and 71 unselected TN breast carcinomas were screened for
PTEN mutations and assessed for PTEN expression and BRCA1 mRNA expression. Loss of PTEN expression was observed in 67% of BRCA1 tumours and more specifically in 89% of TN BRCA1 tumours highlighting the link between PTEN loss and BLBC in the context of germline BRCA1 mutations. Regarding unselected TN tumours, 56% showed PTEN expression loss and 35% displayed low BRCA1 mRNA expression. Unlike familial breast cancers with low BRCA1 mRNA expression, no significant correlation was observed between the loss of PTEN expression and low BRCA1 mRNA expression in this unselected TN tumours panel. Our data suggest that, unlike
the germinal context, PTEN and BRCA1 alterations in sporadic TN breast tumours are independent events.
Keywords
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Article info
Publication history
Published online: February 24, 2022
Accepted:
February 21,
2022
Received in revised form:
January 31,
2022
Received:
October 19,
2021
Identification
Copyright
© 2022 Elsevier Inc. All rights reserved.
