Understanding resistance to EGFR targeted therapies in head and neck cancers and breast cancer

A new review was published in Volume 16 of Oncotarget on June 25, 2025, titled "Challenges and resistance mechanisms to EGFR targeted therapies in head and neck cancers and breast cancer: Insights into RTK dependent and independent mechanisms."

Researchers from the University of Cincinnati and Cincinnati Veterans Affairs Medical Center reviewed current research on why Epidermal Growth Factor Receptor (EGFR)-targeted therapies often fail in breast and head and neck cancers. The article by Shreya Shyamsunder, Zhixin Lu, Vinita Takiar, and Susan E. Waltz explores how cancer cells evade these treatments by activating alternative survival pathways. This review offers an in-depth look at the molecular barriers to EGFR inhibition and provides insights that could inform the development of more effective and durable treatments.

EGFR is a critical protein that regulates cell growth and survival, and it is frequently overexpressed in breast and head and neck cancers. Although therapies targeting EGFR showed early promise, resistance has become a significant challenge. In breast cancer, resistance mechanisms include the movement of EGFR from the cell surface into the nucleus, where it promotes DNA repair, as well as ligand-dependent activation that helps tumor growth despite therapy. In head and neck cancers, resistance often arises from inflammatory signaling through the TLR4-MyD88 pathway and the loss of tumor suppressor genes like PTEN, which allow cancer cells to bypass EGFR inhibition. The review also describes how tumor cells in both cancers commonly activate other receptor tyrosine kinases (RTKs), such as MET, AXL, and RON, to continue growing even when EGFR is blocked.

By analyzing these resistance mechanisms, the authors highlight combination therapies from current research that target EGFR and other key molecular pathways. Strategies such as dual inhibition of EGFR and MET or blocking inflammation-driven survival signals may enhance treatment outcomes. Several clinical trials are evaluating these approaches in patients. For example, in breast cancer, combinations of EGFR inhibitors with chemotherapy and immune checkpoint inhibitors are being tested to improve responses, particularly in triple-negative breast cancer. In head and neck cancers, trials are investigating EGFR-blocking antibodies like cetuximab combined with immunotherapies such as pembrolizumab and nivolumab. These efforts aim to overcome resistance and provide more effective treatment options for patients with EGFR-driven tumors. The review also emphasizes the necessity of identifying biomarkers to predict which patients are most likely to benefit from EGFR-based therapies.

"A recent phase 1 study has shown that patients with recurrent or metastatic head and neck cancer who received BCA101, a bifunctional dual targeting drug that targets EGFR and TGF-β in combination with pembrolizumab, were able to achieve an overall response rate of 65%."

This work brings together current knowledge about EGFR resistance and illustrates the difficulties involved in treating breast and head and neck cancers. By mapping the many ways tumors overcome EGFR inhibition, the review highlights opportunities for more tailored and effective treatments in the future.