Determination of steroid hormone-dependency of tumours utilizing tissue sections. Survey of histochemical techniques and their application in surgical pathology

Oestrogen and progesterone receptor immunocytochemistry in human hyperplastic and neoplastic endometrium

Proliferative disorders of the endometrium may be associated with autocrine and paracrine actions between stromal and epithelial cells. To determine whether the stromal-epithelial relation with respect to oestrogen receptor (OR) and progesterone receptor (PR) is disturbed in (pre)malignant endometrium immunocytochemical OR and PR expression was quantitated by computerized image analysis. This was studied in the stromal and epithelial cells of endometrial specimens diagnosed as hyperplasia (n = 14), atypical hyperplasia (n = 16), and adenocarcinoma (n = 33). Paraffin sections were used for optimal preservation of histomorphology. A progressive loss of OR and PR content occurred with increasing malignant transformation. Stromal cells in atypical hyperplasia (P = 0.0007) and well-differentiated adenocarcinoma (P = 0.0008) exhibited a relative loss of PR content as compared with epithelial cells (P = 0.036 and P = 0.17, respectively). In atypical hyperplasia, the decrease in stromal PR content was not in parallel with persistent stromal OR immunostaining. Furthermore, stromal PR expression in atypical hyperplasia was significantly (P = 0.004) lower than in the surrounding hyperplasia, whereas the stromal OR staining as well as the epithelial OR and PR staining did not differ significantly. These observations may reflect a disturbance in hormonal interrelationships between endometrial cells in the development of endometrial neoplasia, indicating that stroma may modulate epithelial growth by paracrine mechanisms.

Quality control in immunocytochemistry: experiences with the oestrogen receptor assay

AIMS

To evaluate the feasibility of an interlaboratory quality control programme in immunohistochemistry.

METHODS

Several pathology laboratories were asked to carry out immunohistochemical oestrogen receptor staining on a set of freeze dried cryostat sections of breast cancer tissue. The sections and protocols for staining and semi-quantitative scoring were mailed to the participating laboratories in two trials. The oestrogen receptor content of the breast cancer samples was determined by radioligand binding assay on the tumour cytosol.

RESULTS

In the first trial 11 laboratories (response rate 60%) participated. Eight (73%) of the participants scored within a 95% confidence interval and all but one correctly classified the tumour as receptor positive. In the second trial all 20 participating laboratories (response rate 55%) correctly scored one tumour sample as negative and 18 of them (90% of respondents) correctly classified the two other tumour samples as receptor positive. In a quantitative evaluation a histochemical score within 95% confidence interval limits was provided by eight (40%) and 12 (60%) of the participants.

CONCLUSIONS

Semiquantitative scoring of immunocytochemical staining is valuable for performing correlative inter-laboratory studies, although this scoring protocol may not be required for diagnosis or prognosis. Significant inter-laboratory variability exists, leading to qualitatively correct receptor classification in 100% of receptor negative and 80% of receptor positive cases, and quantitative agreement in only about half of the cases. The perceived variability is not caused by systematic differences in the choice of the immunocytochemical technique, or the mailing of freeze dried sections. Quality control programmes should be included in the standard procedures of each diagnostic immunohistochemistry laboratory.

Immunohistochemical study of androgen receptor in benign hyperplastic and cancerous human prostates

Androgen receptor was detected immunohistochemically in benign as well as malignant prostatic tissues by using a monoclonal rat anti-human androgen receptor antibody (AN 1-15). In both benign and malignant cells, the androgen receptor was exclusively localized in nuclei. In hyperplastic prostate, the androgen receptor was stained in the glandular and the stromal cells. In the gland, cells facing the lumen were stained more intensively than those adjacent to the basal membrane. In cancer tissue, receptor-positive and -negative cancer cells were intermingled. The percent of strongly positive cancer cells was correlated inversely with grade. Relapsed cells showed a low population of strongly positive cells irrespective of grade.

Steroid receptors and giant cell tumor of bone

The cell of origin and giant cell tumor remains unknown, but on the basis of most experimental evidence it is probably a mesenchymal cell showing some macrophage characteristics. The clinical features which have led people to suggest that this tumor may be a steroid receptor positive lesion are tenuous at best. Early histochemical data suggesting a presence of estrogen and progesterone receptors in giant cell tumor have not been substantiated by further studies. Immunohistochemical techniques have not identified estrogen receptors in giant cell tumor. Multiple biochemical techniques have failed to identify clinically significant levels of estrogen or progesterone receptors in giant cell tumor.

An evaluation of potentially suitable fixatives for immunoperoxidase staining of estrogen receptors in imprints and frozen sections of breast carcinoma

The estrogen receptor (ER) content of breast carcinoma is generally accepted as valuable in predicting clinical outcome and tumour response to hormonal manipulation. We applied a new immunocytochemical assay for estrogen receptors (Abbott ERICA Monoclonal) to 20 breast tumours, and examined the efficacy of 16 fixation procedures before immunoperoxidase staining of frozen sections and imprint preparations. Our findings indicate that the fixatives of choice are periodatelysine-paraformaldehyde at 22 degrees C, or 10% formalin followed by acetone at -10 degrees C. These fixation procedures are simpler, less time-consuming, and provide superior staining, tumour cytomorphology and higher ER values than the 3-reagent sequence recommended by Abbott Laboratories. There was a significant correlation between the ER scores in the frozen sections and the imprints. Positive ER cytosol results correlated with the staining index in the frozen sections, and the ER scores in the imprints. We conclude that imprints are suitable preparations for ER analysis by the immunoperoxidase technique, particularly for small tumour specimens.

Relationships between oestrogen receptor,epidermal growth factor receptor, ER-D5, and P24 oestrogen regulated protein in human breast cancer

Proteins regulated by or related to the oestrogen receptor (ER) may prove to be more reliable indicators of prognosis and hormone sensitivity then expression of the receptor itself. It has been shown recently that expression of epidermal growth factor receptor (EGFR) is associated with a poor prognosis in breast cancer. In a series of 60 breast cancers, we have studied relationships between ER, ER-D5 oestrogen receptor related protein, P24 oestrogen regulated protein, and EGFR using an immunohistochemical technique employing monoclonal antibodies in each case. In addition, radioligand binding assays for ER and EGFR were carried out and tumour histological grade was determined. Seventy-one per cent and forty-three per cent of tumours stained for ER-D5 and P24, respectively, but there was no relationship between staining for these and ER or EGFR status. There was a significant correlation between staining for ER and EGFR, and the respective biochemical assays. Relating ER to EGFR, very few ER-positive cases expressed EGFR, but this relationship fell short of significance. The prognostic significance of expression of the epitopes recognized by the ERD5 and P24 antibodies must await assessment of clinical outcome.

Quantification of oestrogen receptors in breast cancer: radiochemical assay on cytosols and cryostat sections compared with semiquantitative immunocytochemical analysis

A radiochemical oestrogen receptor assay on cytosol was correlated with a radiochemical and an immunohistochemical oestrogen receptor assay using cryostat sections from 50 breast cancer specimens. Oestrogen receptors were reliably quantitated in 6 micron cryostat sections with Scatchard analysis using radiolabelled oestradiol, and a good quantitative and qualitative relation with cytosol oestrogen receptor assay was found. Parallel sections were used for routine histological tissue verification and for direct comparison with immunohistochemistry for oestrogen receptor. Specific immunoperoxidase staining with a rat monoclonal antibody was scored by semiquantitative evaluation of the staining intensity of cancer cell nuclei. Oestrogen receptor scoring was highly reproducible when performed by the same observer. The semiquantitative immunohistochemical oestrogen receptor score correlated significantly better with the radiochemical assay on sections than with cytosol assay. Oestrogen receptor in breast cancer can be reliably assayed by semiquantitative evaluation of cryostat sections immunostained for oestrogen receptor, but only if the procedure is adequately standardised. The results underline the importance of cellular heterogeneity as a cause of variation in oestrogen receptor assay evaluation in breast cancer.