HSPB1 and nonpapillary renal cell carcinoma: To investigate whether LMP actually occurred in ccRCC cells after Tat-hspb1 treatment, we first stained untreated and Tat-hspb1-treated 786-O cells with acridine orange (AO) [34], which accumulated in the lysosomes and exhibited red fluorescence in the acid compartment of the intact lysosomes but emitted green fluorescence when the lysosomal membrane integrity was disrupted.