This book explores in depth the role of EGFR in cancer, focusing on the challenges and opportunities associated with targeting this key protein. It examines the mechanisms of receptor activation, the challenges posed by mutational heterogeneity, and the potential effects of reactive chemicals and pollutants on the efficacy of EGFR tyrosine kinase inhibitors. In addition, the book highlights current and future research aimed at elucidating these mechanisms and developing new therapeutic strategies to combat cancer. Ultimately, this book aims to provide readers with an in-depth understanding of EGFR and its role in cancer, while highlighting the importance of ongoing research in this field.