However, as discussed earlier, since tissue protein quantitation using ELISA assay is influenced by both biological expression of the target protein and the percentage of epithelial cells expressing the proteins, further analysis needs to be done to determine the percentage of epithelial cells in order to elucidate the biological expression of EpCAM and CTSL between normal prostate tissues and prostate tumors. Here, EPCAM is linked to prostate neoplasm.