ERBB receptors, including EGFR, HER2, HER3, and HER4, are critical in cancer development and progression. These receptors, when dysregulated, drive tumor growth and survival through signaling pathways such as PI3K/AKT, MEK/ERK, and STAT. Targeting these receptors with specific inhibitors has led to improved outcomes in cancers like HER2-positive breast cancer and EGFR-mutant lung cancer. However, resistance to these therapies remains a challenge, often due to alternative signaling pathways or mutations in the receptors themselves. HER2 is a key driver in breast cancer, with amplification leading to aggressive tumor growth. HER2-positive cancers show improved survival with HER2-targeted therapies like trastuzumab. However, resistance can occur through HER2 mutations, alternative splicing, or activation of other pathways. Similarly, EGFR mutations in lung cancer are common and often lead to resistance to first-generation EGFR inhibitors, necessitating the development of second- and third-generation inhibitors. HER3, while not a kinase itself, acts as a scaffold for signaling when dimerized with HER2 or EGFR. HER3 is essential for PI3K/AKT signaling, and its inhibition can enhance the efficacy of HER2-targeted therapies. HER4, though less studied, also contributes to signaling pathways. Resistance mechanisms include bypass signaling through other RTKs, such as MET or IGF-1R, which can activate alternative pathways. Additionally, mutations in the PI3K/AKT pathway, such as PIK3CA mutations, can confer resistance to HER2 and EGFR inhibitors. These mechanisms highlight the complexity of cancer signaling and the need for combination therapies and biomarker-driven approaches. In summary, ERBB receptor targeting has transformed cancer therapy, but resistance remains a significant hurdle. Understanding the molecular mechanisms of resistance is crucial for developing more effective treatments. Current research focuses on combination therapies, biomarker identification, and novel inhibitors to overcome resistance and improve patient outcomes.ERBB receptors, including EGFR, HER2, HER3, and HER4, are critical in cancer development and progression. These receptors, when dysregulated, drive tumor growth and survival through signaling pathways such as PI3K/AKT, MEK/ERK, and STAT. Targeting these receptors with specific inhibitors has led to improved outcomes in cancers like HER2-positive breast cancer and EGFR-mutant lung cancer. However, resistance to these therapies remains a challenge, often due to alternative signaling pathways or mutations in the receptors themselves. HER2 is a key driver in breast cancer, with amplification leading to aggressive tumor growth. HER2-positive cancers show improved survival with HER2-targeted therapies like trastuzumab. However, resistance can occur through HER2 mutations, alternative splicing, or activation of other pathways. Similarly, EGFR mutations in lung cancer are common and often lead to resistance to first-generation EGFR inhibitors, necessitating the development of second- and third-generation inhibitors. HER3, while not a kinase itself, acts as a scaffold for signaling when dimerized with HER2 or EGFR. HER3 is essential for PI3K/AKT signaling, and its inhibition can enhance the efficacy of HER2-targeted therapies. HER4, though less studied, also contributes to signaling pathways. Resistance mechanisms include bypass signaling through other RTKs, such as MET or IGF-1R, which can activate alternative pathways. Additionally, mutations in the PI3K/AKT pathway, such as PIK3CA mutations, can confer resistance to HER2 and EGFR inhibitors. These mechanisms highlight the complexity of cancer signaling and the need for combination therapies and biomarker-driven approaches. In summary, ERBB receptor targeting has transformed cancer therapy, but resistance remains a significant hurdle. Understanding the molecular mechanisms of resistance is crucial for developing more effective treatments. Current research focuses on combination therapies, biomarker identification, and novel inhibitors to overcome resistance and improve patient outcomes.