Our exploration began with protein–ligand docking studies, employing computational simulations in order to unveil the intricate interactions between IRESSA and key proteins associated with breast cancer, namely Dihydrofolate reductase (PDBID: 4KD7), HER2 Kinase (PDBID: 3RCD), epidermal growth factor receptor (PDBID: 1M17), and NUDT5 (PDBID: 5NWH). The gene discussed is DHFR; the disease is breast cancer.