The relative labeling percentages (cathepsin B and K: 4%; cathepsin S: 1%) were insignificant, except for cathepsin V (27%), the closest homolog of cathepsin L, relative to cathepsin L. Interestingly, U87-MG glioma cell extracts did not present any cathepsin L for detection with the P3 probe. The gene discussed is CTSL; the disease is central nervous system cancer.