Expression of cathepsin D in malignant and in the corresponding non-malignant node-negative laryngeal samples: Correlation with receptors for androgen, glucocorticoid, oestrogen and progesterone

A standard immunoradiometric technique was used to investigate the distribution of the intracellular aspartic proteinase cathepsin D in 33 malignant and in the corresponding histologically-proven non-malignant fragments obtained from lymph node negative patients suffering from larynx cancer. In both tissues the androgen, glucocorticoid, oestrogen and progesterone receptors were also assayed. Our data indicate that cathepsin D was present in both tissues, with level significantly higher (P < 0. 0001) in the cancerous fragments (with a mean of 33 +/- 3.4 pmol/mg protein) than in the corresponding non-cancerous specimen (with a mean of 20.8 +/- 2 pmol/mg protein). A significant positive association (P < 0.001) between cathepsin D and PR concentration values in the cancerous larynx was observed; accordingly, tumours expressing PR had significantly (P = 0.0005) higher cathepsin D levels than the tumours which did not contain the receptor. In contrast, such a relationship was absent in the non-malignant specimens. As regards the other steroid receptors, no significant relationship between them and cathepsin D was observed. We conclude that cathepsin D may have a role also in laryngeal carcinoma and that its association with the PR could indicate a possible role of the receptor in the biology of this disease.