Biphasic Scatchard plots of oestrogen receptors are associated with low pS2 levels in human breast cancers.

In a series of 100 breast tumours, oestrogen receptors (ER) were analysed by Scatchard plots, progesterone receptors (PR) by enzyme immunoassay and pS2 by an immunoradiometric assay. Scatchard analysis gave information on receptor heterogeneity in that there was a large variation in Kd values obtained, from 0.001-2.95 nM. This variation was largely confined to tumours containing less than 70 fmol receptor per mg protein, while tumours with higher receptor concentrations were a more homogeneous population with low Kd values. An obvious correlation between ER and PR was found; moreover, pS2 was correlated to both ER and PR. In addition, 20 of the 100 tumours gave biphasic Scatchard plots, indicating the presence of at least two oestrogen-binding moieties, with Kd values and concentrations both in the range of those of receptors. The tumours displaying biphasic Scatchard plots had very low pS2 expression, regardless of ER concentrations; this was not true for PR. It is suggested that variability in responses to endocrine therapy may be related to the heterogeneity of the ER present in breast tumours.

Computerised counting of tumour infiltrating lymphocytes in 90 breast cancer specimens.

Tumour infiltrating lymphocytes (TILs) implicated in immunologic cytotoxicity were evaluated by immunohistochemistry and digitally counted in serial sections from 90 breast cancers in order to assess their number, the relationships between them and to tumour histology. CD3+, CD4+, CD8+, CD20+, CD25+ and CD56+ lymphocytes were found in 58 (64.4%), 52 (57.7%), 50 (55.5%), 22 (24.4%), 11 (12.2%) and 21 (23.3%) tumours, respectively. There was no difference in the number of TILs between pure infiltrating ductal (NOS) and non-ductal carcinomas, and no relationship between TILs and histological grades was found. CD3+ TILs directly correlated to age, while lymph node negative patients had tumours infiltrated by fewer CD4+ TILs with respect to lymph node positive patients. In 25/90 patients, randomly chosen, the status of peripheral blood lymphocytes was evaluated but no differences with respect to the status found in healthy blood donors was obtained; nonetheless while in some patients CD8+ TILs outnumbered CD4+ TILs in situ, the CD4/CD8 ratio was normal in their peripheral blood. The results show a considerable diversity of TILs among breast tumours, their lack of relationship with the status of the peripheral blood cells, and their potential important relationship with age (CD3+) and lymph node status (CD4+).

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 were significantly associated (Spearman's rank correlation: P < 0.0001) in tumours from lymph node-positive patients (N+), while such association did not reach significance in tumours taken from patients with negative lymph nodes (N-). Moreover, cathepsin D concentrations in pS2-rich tumours (pS2 above the median value, 5 ng mg-1 protein) were significantly higher (Mann-Whitney-Wilcoxon's rank-sum test: P = 0.00001) than 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 receptor (PR) (Spearman's rank correlation: P = 0.022). No significant differences in the expression of pS2 and cathepsin D taken from N+ and N- patients were found. Furthermore, no significant differences in pS2 and cathepsin D expression were obtained by stratifying tumours on the basis of their size (T). pS2 and cathepsin D values obtained in ER-positive/PR-positive tumours did not significantly differ from the values obtained in ER-positive/PR-negative and in ER-negative/PR-positive tumours. We conclude that pS2 could have a role in cathepsin D expression, and that it can be used in the assessment of a functioning oestrogen response machinery in those tumours that express only ER.

Immunohistochemical and immunoradiometric evaluations of total cathepsin D in human larynx.

By using a commercially available immunoradiometric technique (Cath-D-IRMA, Cis BioInt.) the distribution of total cathepsin D (cath-D) in 30 malignant and in the corresponding histologically-proven non-malignant fragments obtained from lymph node negative patients suffering from larynx cancer was investigated. In both tissues the oestrogen and progesterone receptors were also assayed. In 17 out of the 30 samples, the cath-D was also assayed by immunohistochemistry using the M1G8, a mouse monoclonal antibody raised against cath-D (Cis BioInt.). Our data indicate that cath-D is present in prismatic cells of the normal laryngeal epithelium and in the cancerous cells. In cancerous larynx, the outer cell layer of large tumour nests showed the highest degree of immunoreactivity, while fibroblasts and inflammatory cells always showed a very faint staining. Cathepsin D levels were 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 cath-D and progesterone receptor (PR) concentration values in the cancerous larynx was observed; accordingly, tumours expressing PR had significantly (P = 0.0005) higher cath-D levels than the tumours which did not contain the receptor. In contrast, such a relationship was absent in the non-malignant specimens. As regard the oestrogen receptor, no significant relationship between this and cath-D was observed. We conclude that cath-D measured by IRMA in tissue cytosols is mainly derived from cancerous cells, the contribution from fibroblasts and inflammatory cells being negligible. Cathepsin D overexpression and association with the PR in the malignant part of the larynx could indicate a possible role of the receptor in the biology of this disease.

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.

p53 associated with cathepsin D in primary breast cancer.

The p53 protein was identified in primary breast carcinomas by specific binding of PAb1801 and PAb240 antibodies. Using sodium dodecyl sulfate electrophoresis followed by immunoblotting on nitrocellulose membrane, the p53 protein was identified in 36 nuclear fractions obtained from 60 primary breast cancers; semiquantitation of p53 was performed by densitometric scanning. The total cathepsin D content, the estrogen and progesterone receptor concentration values and the axillary lymph node involvement were also assessed. Tumors expressing p53 had significantly higher levels of cathepsin D than those in which p53 was undetectable. p53 expression was strongly associated with low or negative estrogen receptor values; progesterone receptor concentrations were also significantly higher in p53-negative tumors than in those tumors with detectable p53 levels. Finally, a significant relationship between p53 expression and lymph node metastasis was observed. It was concluded that a positive association between p53 and cathepsin D values exists which is of prognostic interest in that both cathepsin D and p53 are associated with a high tumor grade and metastatic activity.

Transcriptionally active non-ligand binding oestrogen receptors in breast cancer.

Data were obtained on soluble oestrogen (ER) and progesterone (PR) receptors from 273 primary breast tumours, using an enzyme immunoassay (EIA) and ligand binding assay with dextran-coated charcoal (DCC) or isoelectric focussing separations. The p29 and total cathepsin D content was also assayed in the same samples. Tumours expressing ER (by either steroid binding assay or EIA) had higher levels of p29 than those which did not express the receptor (P < 0.0001). Moreover, tumours co-expressing ER, PR and p29 appeared to have higher levels of cathepsin D than those which were negative for at least one protein (P < 0.0001). Twenty out of the 273 human breast cancer samples, containing a level of ER positive by EIA, which did not bind labelled oestradiol, were identified; isoelectric focussing showed that such a receptor was also unable to bind hydroxytamoxifen. These tumours did not significantly differ from those in the whole population in their capacity to express ER (positive by EIA), PR, p29 and cathepsin D. It was concluded that the EIA can detect both a ligand binding ER and a receptor which is able to initiate PR transcription but does not bind radio-labelled ligands in vitro; such a receptor could have a bearing on the variability of tumour response to endocrine therapy.

Type II oestrogen binding site is associated with the major 4S oestrogen receptor isoform in breast tumours.

Using high resolution isoelectric focusing we have been able to identify a low affinity/high capacity oestrogen binding protein, which exhibits an apparent pI of 7.0. Using this system it can be separated from the previously described high affinity oestrogen receptor (ER) isoforms which focus at pI 6.1, 6.3, 6.6 and 6.8. The pI 7.0 protein was detected in 30/30 breast tumours analysed and had the binding characteristics of the cytoplasmic Type II ER (Kd = 88 +/- 8 nM). The concentration of this protein was shown to be significantly correlated with the concentration of the pI 6.6 species, which represents the major 4S isoform. It is not related to any other isoform of ER, and is expressed independently of the progesterone receptor. The importance of this observed relationship with respect to ER function remains obscure, but it may provide new insights into the role of the Type II oestrogen binding site in breast cancer.

Relation of cathepsin D level to the estrogen receptor in human breast cancer.

Seventy-three primary human breast cancers were analyzed to assess the presence of estrogen and progesterone receptors, the p29 protein, and the total cathepsin D status. No significant relationship was found between cathepsin D concentration and the presence of ER or PR, either by Fisher's exact test or Spearman's rank correlation (P greater than 0.1). However, a significant association was found between cathepsin D and p29 (Fisher's exact test, P less than 0.001) and between cathepsin D and steroid receptor status in samples expressing both estrogen and progesterone receptors (positive by steroid binding assay and enzyme immunoassay) (P less than 0.05). This association was more significant in tissues expressing estrogen and progesterone receptors as well as p29 (P less than 0.001). In contrast, cathepsin D synthesis was not related to tumor size, lymph node involvement, or patient's age (P greater than 0.05). Steroid receptors and cathepsin D were also assayed in samples of non-malignant tissue from 16 mastectomies; there was a significantly higher relative concentration of cathepsin D in the malignant specimens (Student's t-test, P less than 0.001).