The levels of BCRP in normal organs (kidney, liver, small and large intestine, heart, lungs, muscles, and tumor tissue) from healthy and S91 melanoma tumor-bearing DBA/2 mice were examined using the Western blotting (WB) technique, with the use of an anti-BCRP antibody (BXP-53) and an anti-β-actin antibody as reference. This evidence concerns the gene ACTB and neoplasm.