Comparison of microscopic imaging strategies for evaluating immunocytochemical (PAP) steroid receptor heterogeneity

Computer based receptogram approach: an objective way of assessing immunohistochemistry of androgen receptor staining and its correlation with hormonal response in metastatic carcinoma of prostate

AIMS

To categorise the immunostaining heterogeneity of androgen receptors in metastatic carcinoma of the prostate using a pattern oriented approach and to correlate the results with response to hormonal treatment.

METHODS

Paraffin wax embedded tumour sections from 85 patients with metastatic carcinoma of the prostate were processed for immunocytochemistry and stained for the androgen receptor using antiandrogen receptor antibodies. A computer based image analysis system was used to analyse the pattern of nuclear immunostaining in a minimum of 500 nuclei/slide. Depending on the nuclear receptor content and concentration, receptogram patterns were established for each specimen. The receptogram pattern was correlated with clinical response to hormonal treatment.

RESULTS

Clinical response to hormonal treatment was documented using prostate specific antigen as the marker into responders (good, fair, stable) and non-responders. Forty four of 48 patients who responded to hormonal treatment had type 1 (35) or type 3 (nine) receptograms, which are characterised by a unimodal peak or multimodal peaks within a narrow concentration range. Thirteen of the 18 patients who stabilised had type 1 or type 3 receptograms. Seventeen of the 19 patients who did not respond to hormonal treatment had either type 2 or type 4 receptograms, which are characterised by skewed or bimodal androgen receptor distribution. Positive and negative predictive values of receptograms were 96.5% and 63%, respectively.

CONCLUSIONS

Image analysis of androgen receptor immunostaining with a receptogram oriented approach provides important prognostic information that can be used to predict response to hormone treatment in patients with metastatic carcinoma of the prostate.

Steroid Hormone Receptor Immunohistochemistry in Breast Cancer: Past, Present, and Future

This article reviews the development of steroid hormone receptor detection using the biochemical approach and the disadvantages inherent in these systems. The early history of methods for the in situ detection of receptors is related, culminating in the development of histologic immunoassays using monoclonal antibodies. Correlation of the latter with disease-free and overall survival and with clinical endocrine response are presented together with preliminary findings utilizing a new generation of antireceptor antibodies. Current problems with test scoring and interpretation are detailed with a section devoted to image analysis for assay quantification. Emphasis is placed on the fact that because so many different antibodies and tissue substrates have been employed in the past, these histologic receptor immunoassays cannot yet be considered to be fully validated. It is stressed that different laboratories must employ the same antibodies, substrates, detection systems and methods of scoring, and then correlate findings with measurable clinical end points. Only then can the assays be included in the brief list of approved breast cancer prognostic and predictive markers to eventually replace the routine biochemical methods of steroid receptor detection.

Image cytometric analysis in pathology

Image cytometry (ICM) is used in surgical pathology to quantify nuclear DNA content, nuclear and cytoplasmic immunostain. DNA aneuploidy is shown to be an independent negative prognostic factor in malignant melanoma, small cell carcinoma of the lung, esophageal, ovarian, endometrial, prostatic, urinary bladder, and papillary thyroid carcinoma. On bladder washings, DNA ploidy by ICM is used as an aid in diagnosis and management of recurrent transitional cell carcinoma of the bladder. Quantitation of nuclear immunostain for proliferation markers by ICM has clinical significance in prognosis and management of solid tumors of bladder, breast and ovary, astrocytoma, lymphoma, and malignant melanoma. Angiogenesis, measured by microvessel density is a predictor of prognosis in breast carcinoma and an independent predictor of metastasis for breast carcinoma, malignant melanoma, non-small cell lung carcinoma, and prostate carcinoma. Quantitated by ICM, angiogenesis is predictive of the presence or subsequent development of regional lymph node metastases in head and neck squamous carcinomas. Future prospects for ICM in pathology include the standardization of ICM techniques; extended clinical use of DNA ploidy for diagnosis, prognosis and as a help with therapeutic decisions; development of neural networks and quantification of fluorescence in situ hybridization to distinguish benign from malignant lesions of low malignant potential, and three-dimensional reconstruction of morphology from two-dimensional sections measured for prognostic parameters.

Estrogen- and progesterone receptors in normal cycling endometrium as studied by end-point titration

A thorough knowledge of the normal physiological fluctuations in estrogen- (ER) and progesterone receptors (PgR) is essential to characterize the changes in ER and PgR in the abnormal endometrium. We investigated the distribution of ER and PgR in frozen human cycling endometrial tissue using the commercially available ER- and PgR-ICA kits. Two-fold end-point titration (EPT) of ER and PgR antibodies was implemented to semi-quantitate more accurately ER and PgR. Semiquantitation of ER and PgR using EPT was significantly correlated to results obtained using either simple scoring or enzyme-immunoassay (EIA) methods. ER and PgR staining fluctuated in relation to the menstrual cycle. In most subphases PgR exceeded ER in both epithelial and stromal cells. Highest levels of ER and PgR were demonstrated in the glands of the functionalis in mid-to-late proliferative phases, whereas both receptors were almost undetectable by immunohistology in the glands of mid-to-late secretory phases. Endometrial stromal cells had high and nearly constant EPT values for PgR, but low values for ER throughout the menstrual cycle. EPT values for ER and PgR were generally higher in the basalis than in the functionalis but showed similar cyclic fluctuations. Our results further substantiate the view that the response to hormonal stimulation is cell-type specific, and suggest differences in steroid metabolism according to cell type and layer.

Reproducibility of subjective immunohistochemical estrogen- and progesterone receptor determination in human endometrium

To obtain a reliable scoring system for semi-quantitation of estrogen- (ER) and progesterone receptors (PgR) in human endometrial tissue, we investigated the reproducibility of subjective immunohistochemical ER and PgR determination. Specimens of frozen endometrial tissue were stained once (n = 129) or twice (n = 22) using the ER-ICA and PgR-ICA kits from Abbott. The semi-quantitative approach we used included subjective estimates of the overall staining intensity (I) and of the fraction of stained cells (%). Scoring was performed twice by the same observer and once by another observer (n = 87). Intra- and inter-observer agreement were evaluated using Kappa statistics. We found that more comprehensive scorings of I and % could not be agreed upon by the observers. Only simplified estimates of the fraction of cells stained and overall staining intensity were reproducible. Subjective estimates obtained by this method agreed with estimates obtained by counting (n = 38). Simplified H-scores, which were obtained by multiplication of the simplified estimates of % and I, were reproducible, too. In addition, semi-quantitation of ER and PgR by immunohistology was significantly correlated to quantitation by enzyme-immunoassay (n = 39). Thus, it was possible to reproducibly semi-quantitate ER and PgR only by employing a very simple immunohistochemical scoring of ER and PgR.