ABCG2 and squamous cell carcinoma: Collectively, this is the first study to display that PEGylated liposomal epirubicin and TH1-5 lead to cell death in human squamous carcinoma and pluripotent testicular embryonic carcinoma cells through the reduced epirubicin efflux via the TH1-5-mediated inhibition of ABC transporters and the caspase-dependent activation of the intrinsic mitochondrial pathway of apoptosis triggered by epirubicin in the liposomal formulation.