ABCG2 and squamous cell carcinoma: Zhang et al. reported that using BAY-1082439 and CRISPR/Cas9 to knock out Pik3ca and Pik3cb can inhibit the activation of PI3K 110α and 110β catalytic subunits, downregulating ABC transporters P-gp/ABCB1 and BCRP/ABCG2, thereby re-establishing drug sensitivity in resistant epidermoid carcinoma and non-small cell lung cancer (NSCLC) cells[148].