Researchers at Ben-Gurion University of the Negev have made a groundbreaking discovery in the fight against triple-negative breast cancer (TNBC), a particularly aggressive and difficult-to-treat form of breast cancer. Their work has identified a crucial protein, protein kinase C-eta (PKC-eta), that plays a central role in enabling the metastatic spread of cancer cells. Metastasis—the process by which cancer cells move from the primary tumor site to other vital organs such as the lungs, liver, and brain—is the primary cause of mortality in breast cancer patients. This new insight into PKC-eta’s function offers a promising target for therapeutic intervention aimed at halting the deadly progression of the disease.
Triple-negative breast cancer lacks the expression of estrogen receptors, progesterone receptors, and human epidermal growth factor receptor-2 (HER2), which limits the efficacy of common hormone and targeted therapies. Consequently, TNBC patients often face poorer prognoses and higher rates of recurrence and metastasis. The research team from Ben-Gurion University, led by Professors Etta Livneh and Moshe Elkabets along with postdoctoral fellow Liju Vijaya Steltar, utilized an integrated approach combining detailed patient tumor data analysis, cell culture experiments, and rigorous animal model testing to unravel the molecular mechanisms by which PKC-eta contributes to cancer progression.
Their investigations revealed that PKC-eta significantly enhances the motility and invasiveness of breast cancer cells. On a molecular level, PKC-eta activates specific gene programs that empower cancer cells to detach from the primary tumor, navigate through the extracellular matrix, intravasate into the bloodstream, and eventually colonize secondary sites across various distant organs. This protein exerts its influence through direct interaction with the YAP protein, a pivotal effector in the Hippo signaling pathway, which is deeply implicated in controlling organ size, tissue homeostasis, and tumorigenesis, especially metastasis.
The Hippo–YAP pathway has garnered increased attention for its regulatory roles in cancer biology. YAP (Yes-associated protein) is known to act as a transcriptional coactivator that promotes gene expression patterns facilitating cell survival, proliferation, and migration. In this study, PKC-eta was shown to physically bind to and activate YAP, thus driving the expression of downstream genes that orchestrate the metastatic cascade. This revelation places PKC-eta as a novel upstream modulator of Hippo–YAP signaling in breast cancer metastasis, and specifically in the highly aggressive TNBC subtype.
When the researchers experimentally reduced PKC-eta expression or activity in both in vitro cell models and in vivo mouse models, the results were profound: tumor growth rates declined, and metastatic spread to critical organs such as the lungs and liver was substantially diminished. This direct correlation underscores PKC-eta’s potential as both a prognostic biomarker for aggressive tumors predisposed to metastasis and as a therapeutic target whose inhibition may improve patient outcomes by curbing metastatic disease progression.
Intriguingly, the research team did not stop at characterizing the pathogenic role of PKC-eta; they also identified a naturally occurring peptide encoded upstream of the PKC-eta mRNA sequence capable of targeting and degrading PKC-eta protein itself. In laboratory assays, introducing this peptide disrupted the regulatory influence of PKC-eta on YAP1, leading to a significant reduction in the migratory and invasive properties of cancer cells. This finding hints at a novel class of peptide-based therapeutics that could selectively degrade PKC-eta, effectively neutralizing its pro-metastatic function.
Such a molecularly targeted approach offers distinct advantages over conventional chemotherapy by potentially minimizing toxicity and improving specificity against metastatic breast cancer cells carrying high PKC-eta expression. The prospect of advancing this peptide through preclinical and clinical development could revolutionize treatment options for TNBC patients, a population currently underserved by existing anti-cancer drugs.
The study’s comprehensive methodology involved using patient tumor samples to correlate elevated PKC-eta levels with molecular markers indicative of poor clinical prognosis. This translational approach ensures the findings have direct relevance to human disease outside the experimental settings. The amalgamation of basic science, cell biology, and translational oncology in this work exemplifies the type of multidisciplinary research required to tackle complex cancers like TNBC.
Although promising, the authors acknowledge that these initial findings derived from cell culture and animal models require extensive further validation to assess safety, efficacy, and optimal delivery mechanisms for therapeutic peptides targeting PKC-eta in human patients. The molecular intricacies of PKC-eta and YAP interactions will also need deeper exploration to refine strategies that can exploit these pathways without disrupting normal cellular functions governed by Hippo signaling.
This research was made possible by generous funding from multiple prestigious sources, including the Israel Science Foundation, the Israeli Ministry of Science, Technology and Space, the U.S.–Israel Binational Science Foundation, and the Israel Cancer Research Foundation. The research team also benefited from a Kreitman Postdoctoral Fellowship awarded by Ben-Gurion University. Collaborative efforts such as this highlight the critical nature of international scientific partnerships in advancing cancer research worldwide.
In summary, the identification of PKC-eta as a pivotal regulator of breast cancer metastasis via the Hippo–YAP signaling pathway opens a compelling new avenue for tackling one of the deadliest mechanisms of cancer progression. The discovery of an endogenous peptide that degrades PKC-eta amplifies the translational potential of this research. If future clinical studies confirm these findings, PKC-eta-targeting therapies could dramatically alter the course of treatment for patients afflicted with triple-negative breast cancer, reducing mortality and improving long-term survival.
Such cutting-edge insights reflect the urgent need to go beyond tumor removal alone and to target the molecular machinery driving metastasis. By intervening in the metastatic cascade at the protein-signaling level, this new research could bring hope to a patient population that has long faced limited treatment options and poor prognoses. Continued investigation into PKC-eta and allied pathways promises to be a fertile ground for therapeutic innovation in the coming years.
Subject of Research: Cells
Article Title: PKC-eta promotes breast cancer metastasis by regulating the Hippo–YAP signaling pathway
News Publication Date: April 16, 2026
Web References: http://dx.doi.org/10.1038/s41392-026-02572-0
Keywords: Triple-negative breast cancer, PKC-eta, metastasis, Hippo signaling pathway, YAP protein, cancer cell migration, breast cancer treatments, peptide therapeutics, cancer biomarkers
