Expression of cathepsin D in head and neck cancer.

To determine overexpression of cathepsin D in head and neck tumours we examined cytosols from 53 primary tumours, nine cytosols of lymph node metastases and 12 cytosols from adjacent normal tissue. We found a significantly lower concentration in normal tissue compared with tumour cytosol as well as with metastases, even when we compared tumours and corresponding metastases pairwise. In addition, we found a significantly higher concentration of cathepsin D in five lymph node metastases than in the corresponding tumours. We conclude that the reported role of cathepsin D is not restricted to breast cancer but could also be important in head and neck cancer.