Steroid receptor measurement in breast cancers: comparison between ligand binding and enzyme-immunoassay in cytosolic and nuclear extracts

Quantitative fluorescence cytometric measurement of estrogen and progesterone receptors: correlation with the hormone binding assay

We describe, here, a rapid flow cytometry technique for the detection and quantification of estrogen (ER) and progesterone (PgR) receptors in several human cell lines and in clinical samples obtained from breast cancer tumors. ER and PgR quantitation can be very useful in patients with breast cancer as their role in diagnosis and prognosis is well established. However ligand binding assays and immunohistochemical assays are difficult to measure heterogeneity in individual cells. On the other hand, flow cytometry is a convenient tool for quantification in individual cells. Flow cytometric results with breast cancer cell lines and clinical samples were compared to those obtained by quantitative biochemical ER and PgR performed by the standard dextran-coated charcoal biochemical assay. The latter assay is affected by the level of endogenous steroids. This is also the case in the routine measurement of ER/PgR in patient's tumor cells whereby estradiol molecules in patient's serum produced negative or low values in the biochemical assay. The mAbs used in our flow cytometric method bind to their specific ER or PgR independently of whether they are preoccupied by their ligands and they produce reliable results. With the use of beads calibrated in MESF (Molecules of Equivalent Soluble Fluorochrome) units, the ER and PgR can be measured on a per cell basis. The flow cytometric method showed a strong correlation with biochemical receptor assessments of either ER alpha (ER alphaDCC, r = 0.918, p = 0.073) or PgR (PgRDCC, r = 0.75, p = 0.001). This study demonstrates that ER alpha and PgR can be detected by flow cytometry on a per cell basis in intact cells, and can be quantitated reliably in terms of MESF without the limitations of competition with serum's estradiol molecules.

Pathologic and biological prognostic factors of breast cancers in short- and long-term hormone replacement therapy users

BACKGROUND

Breast cancer tumors occurring in hormone replacement therapy (HRT) users are less aggressive, but no studies have compared tumor aggressiveness among HRT users by length and mode of therapy.

METHODS

A total of 1105 consecutive postmenopausal patients treated for operable breast cancer at the European Institute of Oncology were identified. Women exposed to HRT were compared with HRT nonusers by clinical stage at presentation and pathologic and biological tumor characteristics. HRT duration and administration modality were analyzed in relation to tumor characteristics in the HRT group.

RESULTS

Better stage distribution, including smaller pathologic tumor diameter and fewer involved axillary lymph nodes, was seen in the HRT group. Estrogen receptor-positive tumors were more frequent in the control group, but this tendency was reversed with longer exposure to HRT. Histological grade III tumors were less frequent in the HRT group. More favorable prognostic factors were associated with HRT >5 years. The proliferative fraction was higher in patients with exposure <1 vs. >5 years and in oral versus transdermal users.

CONCLUSIONS

Breast cancers developing during HRT have better prognostic characteristics than those seen in HRT nonusers. A trend toward better prognostic characteristics with increasing duration of HRT was seen.

Evaluation of prognostic factors in male breast cancer

We conducted an analysis on 41 cases of male breast cancer (median age 54 y; range 25-82 y) in Kuwait. Most (51%) were stage II cancers with 65% arising in the left breast. There were 5 (12%) T1 tumours, 23 (56%) T2 tumours and 13 (32%) T3/T4 tumours. They were mostly (95%) infiltrating ductal carcinomas; 97% were grade 2 or 3. Axillary lymph node involvement was found in 69%. Estimated 5-year survival rates were 67% and 58% for overall and relapse free survival respectively. Favourable prognosis was associated with age below 50y, clinical stage I and II, small tumour size (T1, T2), low tumour grade and absence of nodal involvement or distant metastases; nodal status and grade were independent factors for relapse free survival in multivariate analysis. In 18 cases, an immunohistochemical study showed some degree of tumour antigen reaction for ER in 89% of cases, PR in 61%, pS2 in 44%, CathD in 72%, p53 in 56%, c-erbB-2 in 50%, Ki67 and PCNA in 100% and bcl-2 in 78%. There were significant associations between several of these factors but none influenced survival. Despite the high incidence of staining of ER, our data do not support the concept of an endocrine pathway that could be usefully antagonized with antioestrogens for therapeutic benefit, as in women.

Cytosol concentrations of CD44 isoforms in breast cancer tissue

The role of the adhesion molecule CD44 in the natural history of breast cancer is controversial. We investigated the CD44 isoform CD44v5 and CD44v6 concentrations in the cytosol of 90 breast cancer specimens, 9 fibroadenomas and 22 normal breast tissue specimens by means of ELISA. CD44v5 and CD44v6 cytosol concentrations were statistically significantly higher in breast cancer compared with fibroadenoma and normal breast tissue (Mann-Whitney U-test, p = 0.009 and p < 0.001, respectively). When CD44 isoforms were correlated with lymph node involvement, histological grading, histological type, tumor stage and age at diagnosis, we found no statistically significant correlation with any of the investigated clinico-pathological parameters. In univariate and multivariate analyses, CD44v5 and CD44v6 were of no prognostic relevance regarding disease-free survival in breast cancer patients (log-rank test, p = 0.16 and p = 0.08, respectively). Our results indicate that CD44 isoforms are increased in samples from tumors relative to normal tissue. Our data show that CD44v5 and CD44v6 isoform expression, although up-regulated by malignant transformation, is not required to acquire a metastatic phenotype in breast cancer. Furthermore, our data support the assumption that cytosolic CD44 isoforms are of no prognostic relevance for disease-free survival of breast cancer patients.