IMMUNORADIOMETRIC DETECTION OF PS2 AND TOTAL CATHEPSIN-D IN PRIMARY BREAST-CANCER BIOPSIES - THEIR CORRELATION WITH STEROID-RECEPTORS

Commercially available immunoradiometric assays were used for pS2 and total cathepsin D determination in the cytosol fraction obtained from 266 primary breast cancers. We show that pS2 and cathepsin D values we re significantly associated (Spearman's rank correlation: P<0.0001) in tumours from lymph node-positive patients (N+), while such associatio n did not reach significance in tumours taken from patients with negat ive lymph nodes (N-). Moreover, cathepsin D concentrations in pS2-rich tumours (pS2 above the median value, 5 ng mg(-1) protein) were signif icantly higher (Mann-Whitney-Wilcoxon's rank-sum test: P = 0.00001) th an those obtained in the samples expressing less than 5 ng of pS2 per mg of protein. pS2 was also correlated to both the oestrogen receptor (ER) (Spearman's rank correlation: P<0.0001) and the progesterone rece ptor (PR) (Spearman's rank correlation: P = 0.022). No significant dif ferences in the expression of pS2 and cathepsin D taken from N+ and N- patients were found. Furthermore, no significant differences in pS2 a nd cathepsin D expression were obtained by stratifying tumours on the basis of their size (T). pS2 and cathepsin D values obtained in ER-pos itive/PR-positive tumours did not significantly differ from the values obtained in ER-positive/PR-negative and in ER-negative/PR-positive tu mours. We conclude that pS2 could have a role in cathepsin D expressio n, and that it can be used in the assessment of a functioning oestroge n response machinery in those tumours that express only ER.