Immunoradiometric assay of pro-cathepsin D in breast cancer cytosol: relative prognostic value versus total cathepsin D.

In breast cancer cell lines, the maturation of pro-cathepsin D into enzymatically active cathepsin D is altered, leading to its increased secretion. In order to specifically assay pro-cathepsin D (52 kD form) in breast cancer cytosol, we monitored a solid phase sandwich radioimmunoassay using D9H8 and D7E3 monoclonal antibodies raised against human pro-cathepsin D from MCF7 cells. Pro-cathepsin D was assayed in 108 primary breast cancer cytosols in which total cathepsin D was previously found to be correlated with metastasis.

Prediction of relapse and survival in breast cancer patients by pS2 protein status.

Application of systemic adjuvant therapy for primary breast cancer patients requires a more accurate identification of patients at high risk for recurrence. We have quantitatively assessed the cytosolic levels of estrogen-regulated pS2 protein in tumors of 205 breast cancer patients (median follow-up, 47 mo). There were no significant associations between the level of pS2 protein and tumor size, lymph node status, and differentiation grade.

Mapping on the calf estrogen receptor of the binding domain for an antibody interfering with receptor activation.

The localization on the calf estrogen receptor of the binding domain for B36 (an IgM antibody which prevents and reverses the effects of receptor activation) has been studied by means of controlled proteolysis of the receptor-estradiol complex using trypsin, chymotrypsin, and papain. We successively determined for intact and proteolyzed receptor-estradiol complex (i) the abilities of estradiol-binding species to aggregate in low salt medium, to bind to nonspecific DNA absorbed onto cellulose, and to interact with B36 antibody in sucrose gradients; (ii) the hydrodynamic properties of estradiol-binding species, by gel permeation chromatography and sucrose gradient centrifugation in high salt media and (iii) the molecular weights of B36-reactive species, by immunoblot analysis. Three tryptic receptor fragments of Mr 36,000, 34,000, and 33,000 and two chymotryptic fragments of Mr 36,000 and 33,000 included both the hormone- and B36-binding domains but did not interact with DNA, whereas at least two receptor fragments resulting from the action of chymotrypsin and papain bound estradiol with high affinity but interacted neither with DNA nor with B36.

A monoclonal antibody to the estrogen receptor inhibits in vitro criteria of receptor activation by an estrogen and an anti-estrogen.

The effect of an IgM class monoclonal antibody (B36) (Greene, G. L., Fitch, F.

A monoclonal antibody to the estrogen receptor discriminates between the nonactivated and activated estrogen- and anti-estrogen-receptor complexes.

An IgM-class monoclonal antibody ( B36 ) [Greene, G. L., Fitch, F.