Increased MAPK1/3 Phosphorylation in Luminal Breast Cancer Related with PIK3CA Hotspot Mutations and Prognosis
Overview
Authors
Affiliations
Introduction: While mutations in PIK3CA are most frequently (45%) detected in luminal breast cancer, downstream PI3K/AKT/mTOR pathway activation is predominantly observed in the basal subtype. The aim was to identify proteins activated in PIK3CA mutated luminal breast cancer and the clinical relevance of such a protein in breast cancer patients.
Materials And Methods: Expression levels of 171 signaling pathway (phospho-)proteins established by The Cancer Genome Atlas (TCGA) using reverse phase protein arrays (RPPA) were in silico examined in 361 breast cancers for their relation with PIK3CA status. MAPK1/3 phosphorylation was evaluated with immunohistochemistry on tissue microarrays (TMA) containing 721 primary breast cancer core biopsies to explore the relationship with metastasis-free survival.
Results: In silico analyses revealed increased phosphorylation of MAPK1/3, p38 and YAP, and decreased expression of p70S6K and 4E-BP1 in PIK3CA mutated compared to wild-type luminal breast cancer. Augmented MAPK1/3 phosphorylation was most significant, i.e. in luminal A for both PIK3CA exon 9 and 20 mutations and in luminal B for exon 9 mutations. In 290 adjuvant systemic therapy naïve lymph node negative (LNN) breast cancer patients with luminal cancer, high MAPK phosphorylation in nuclei (HR=0.49; 95% CI, 0.25-0.95; P=.036) and in tumor cells (HR=0.37; 95% CI, 0.18-0.79; P=.010) was related with favorable metastasis-free survival in multivariate analyses including traditional prognostic factors.
Conclusion: Enhanced MAPK1/3 phosphorylation in luminal breast cancer is related to PIK3CA exon-specific mutations and correlated with favorable prognosis especially when located in the nuclei of tumor cells.
Maitisha G, Zhou J, Zhao Y, Han S, Zhao Y, Abliz A Heliyon. 2023; 9(11):e21759.
PMID: 38034788 PMC: 10681924. DOI: 10.1016/j.heliyon.2023.e21759.
Chen H, Li Q, Yi R, Li B, Xiong D, Peng H J Clin Lab Anal. 2022; 36(2):e24188.
PMID: 35023214 PMC: 8841138. DOI: 10.1002/jcla.24188.
Machida Y, Imai T Oncol Lett. 2021; 22(4):738.
PMID: 34466150 PMC: 8387855. DOI: 10.3892/ol.2021.12999.
Li Y, Wang C, Gao Y, Zhou L J Oncol. 2021; 2021:3632576.
PMID: 34367282 PMC: 8337125. DOI: 10.1155/2021/3632576.