ABCG2 and squamous cell carcinoma: Zhang et al. have been reported that, through the specific inhibition of PI3K 110α and 110β subunits by BAY-1082439, which is a highly selective PI3K inhibitor and via Crispr/Cas9 gene knockout method, P-gp/ABCB1 and BCRP/ABCG2 were downregulated and the drug sensitivity was reestablished in human epidermoid carcinoma and non-small cell lung cancer (NSCLC) MDR cells.