ABCG2 and neoplasm: Furthermore, TAS3351 is not a substrate of P-glycoprotein (P-gp) and the breast cancer-resistant protein (BCRP) and exhibits significant brain penetrability, resulting in anti-tumor efficacy in mice with intracranial allografts.<h4>Conclusions</h4>These findings indicate that TAS3351 is a promising therapeutic candidate for patients with NSCLC whose tumors have relapsed or are refractory to treatment due to the C797S and T790M mutations, and the brain metastases.