Expression of stromelysin 3 in basal cell carcinomas

Stromelysin 3 is a member of the metalloproteinase family, which is express ed in various remodelling processes. The prognosis of breast cancers and sq uamous cell carcinomas is correlated to the level of expression of this pro tein. The purpose of the present work was to evaluate the expression of str omelysin 3 in the major types of basal cell carcinomas. We selected cases o f primary tumours that were fully excised, without previous biopsy: 40 Pink us tumors, 40 superficial, 40 nodular. 38 morpheiform basal cell carcinomas and 10 cases showing deep subcutaneous or muscular invasion. Immunohistoch emistry was carried out using monoclonal anti-ST3 antibodies (MC Rio, IGBMC Strasbourg), and evaluated on a semi-quantitative scale from 0 to 3. Positively stained cells were restricted to the periphery of the epithelial cells, which, by contrast, never expressed stromelysin 3. The global rate of expression was 27% in Pinkus tumors, 65% in superficial. 72.5% in nodula r, 87% in morpheiform and 100% in deeply invasive carcinomas. The rates of tumours showing the highest number of positively stained cells (class 2 or 3) were respectively 7.5%, 20%, 45%, 63% and 100%. This systematic study of stromelysin3 expression in basal cell carcinomas c onfirms that it is a marker of poor prognosis, because the rate of positive tumours was much higher in aggressive carcinomas. Moreover, the majority o f tumours showing an intense expression (i.e. the highest number of positiv ely stained cells in their stroma) were of the morpheiform and deeply invas ive types, which are of poor prognosis. Altogether, the studies performed o n cutaneous tumours are consistent with the theory of stromelysin 3 playing an active role in tumour progression.