PIK3CA mutations in breast cancer: A Tunisian series

Mariem Ben Rekaya; Farah Sassi; Essya Saied; Linda Bel Haj Kacem; Nada Mansouri; Sinda Zarrouk; Saifeddine Azouz; Soumaya Rammeh

doi:10.1371/journal.pone.0285413

PIK3CA mutations in breast cancer: A Tunisian series

PLoS One. 2023 May 17;18(5):e0285413. doi: 10.1371/journal.pone.0285413. eCollection 2023.

Authors

Mariem Ben Rekaya¹, Farah Sassi², Essya Saied¹, Linda Bel Haj Kacem^{1

2}, Nada Mansouri³, Sinda Zarrouk⁴, Saifeddine Azouz⁴, Soumaya Rammeh^{1

2}

Affiliations

¹ Faculty of Medicine of Tunis, UR17ES15, University Tunis El Manar, Tunis, Tunisia.
² Pathology Department, Charles Nicolle Hospital, Tunis, Tunisia.
³ Pathology Department, Military Hospital, Tunis, Tunisia.
⁴ Pasteur Institute of Tunis, Genomics Platform, University of Tunis El Manar Tunis, Tunisia.

Abstract

Background: The aim of this study was to analyze PIK3CA mutations in exons 9 and 20 in breast cancers (BCs) and their association with clinicopathological characteristics.

Methods: Mutational analysis of PIK3CA exon 9 and 20 was performed by Sanger sequencing in 54 primary BCs of Tunisian women. The associations of PIK3CA mutations with clinicopathological characteristics were analyzed.

Results: Fifteen exon 9 and exon 20 PIK3CA variants were identified in 33/54 cases (61%). PIK3CA mutations including pathogenic (class 5/Tier I) or likely pathogenic (class 4/Tier II) occurred in 24/54 cases (44%): 17/24 cases (71%) in exon 9, 5/24 cases (21%) in exon 20 and 2/24 cases (8%) in both exons. Of these 24 cases, 18 (75%) carried at least one of the three hot spot mutations: E545K (in 8 cases), H1047R (in 4 cases), E542K (in 3 cases), E545K/E542K (in one case), E545K/H1047R (in one case) and P539R/H1047R (in one case). Pathogenic PIK3CA mutations were associated with negative lymph node status (p = 0.027). Age distribution, histological SBR tumor grading, estrogen and progesterone receptors, human epidermal growth factor receptor 2, and molecular classification were not correlated with PIK3CA mutations (p > 0.05).

Conclusion: The frequency of somatic PIK3CA mutations in BCs of Tunisian women is slightly higher than that of BCs of Caucasian women and more observed in exon 9 than in exon 20. PIK3CA mutated status is associated with negative lymph node status. These data need to be confirmed in larger series.

Copyright: © 2023 Ben Rekaya et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Breast Neoplasms* / genetics
Breast Neoplasms* / pathology
Class I Phosphatidylinositol 3-Kinases / genetics
Female
Humans
Mutation

Substances

Class I Phosphatidylinositol 3-Kinases
PIK3CA protein, human

Supplementary concepts

Tunisian people

Grants and funding

This study was supported by the Tunisian-Algerian project funded by the Tunisian Ministry of high education and research entitled: “Study of tumor biomarkers for theranostic purposes with the aim of setting up validated molecular tests in clinical practice”: PRD/TN/DZ/21/08. The authors state that the funders had no role in study design, data collection and analysis, decision to publish, or preparation of the manuscript.