EFFECT OF TUMOR SIZE ON THE ASSOCIATION BETWEEN PS2 AND CATHEPSIN-D IN PRIMARY BREAST-CANCER

Previous studies have shown that pS2 and cathepsin D are linked in lym ph node positive (N+) tumours, but not in tumours from lymph node nega tive (N-) patients. The purpose of this study was to understand whethe r or not size would effect the relationship between pS2 and cathepsin D. Findings were further extended to some subgroups of tumours obtaine d stratifying for T and N and particularly to the small (TI) but aggre ssive (N+) cancers (T1/N+) and to those of size greater than 2 cm (T2 and T3) but yet node negative (T2+T3/N-). Oestrogen (ER) and progester one (PR) receptors, pS2 and cathepsin D concentrations were therefore assayed in 355 primary breast cancers. ER, PR, pS2 and cathepsin D did not correlate to nodal status and size of the tumours; no significant differences in the expression of these four biological factors betwee n infiltrating ductal carcinomas without special features (NOS) and no n-NOS carcinomas were found. Multivariate analysis performed among cat hepsin D, ER, PR and pS2 indicated that, in T1 tumours, pS2 was the mo st important variable and the best predictor in cathepsin D determinat ion, while such association was absent in T2 and T3 tumours. pS2 and c athepsin D significantly associated also in tumours obtained from N+ p atients, and such correlation was highest in T1 tumours with positive axillary nodes (N+/T1). pS2 and cathepsin D did not associate in tumou rs taken from N- patients. Considering the NOS carcinomas, correlation between pS2 and cathepsin D in the N+, T1 and N+/T1 subgroups was hig her in the poorly differentiated grade 3 with respect to grade 1 and g rade 2 cancers. The data suggest that pS2 could have a role in catheps in D expression and we hypothesise that such control could be an early biological event occurring in the development and progression of part icularly aggressive (N+/grade 3), small (T1) breast cancers.