The prognostic value of the expression of collagenase IV, cathepsin D and metallothionein in squamous cell carcinomas of the skin determined by immunohistochemistry.

We analyzed 53 specimens from primary squamous cell carcinomas of the skin for the expression of collagenase IV, cathepsin D and metallothionein by means of immunohistochemistry along with histological data. We compared tumors that metastasized (30) with tumors that did not (23) during a follow-up period of at least 5 years. The expression of the two proteolytic enzymes cathepsin D and collagenase IV was also assessed at the invading front of the tumors. Statistical analyses revealed significant differences for the overall expression of cathepsin D (P < 0.05), expression of cathepsin at the invading front (P < 0.05) and the tumor thickness (P < 0.01). The results showed that cathepsin D may be a prognostic factor for squamous cell carcinomas of the skin. We then combined the results of parameters with statistically significant differences by multiplication. The prognostic value of such a combined risk-factor score showed higher confidence than any of the single parameters alone: a sensitivity of 63.3%, a specificity of 87.0% and an efficiency of 73.6%. This kind of combined risk-factor score might be used to more accurately detect patients at high risk of metastasis.