Oestrogen receptor assay. False positive analysis?

Aberrant Expression of Androgen Receptor Associated with High Cancer Risk and Extrathyroidal Extension in Papillary Thyroid Carcinoma

Male gender is a risk factor for mortality in patients with papillary thyroid carcinoma (PTC). This study investigated the impact of androgen receptor (AR) gene expression on the clinical features and progression of PTC. The levels of AR mRNA and protein in frozen, formalin-fixed, paraffin-embedded tissue samples from PTC and adjacent normal thyroid tissue were assessed by quantitative real-time polymerase chain reaction and immunohistochemical staining, respectively, and the relationships between AR expression and clinical features were analyzed. The thyroid cancer cell lines, BCPAP and TPC-1, were used to evaluate the effects of AR on the regulation of cell migration, and key epithelial-mesenchymal transition (EMT) markers. AR mRNA expression was significantly higher in normal thyroid tissue from men than women. The sex difference in AR mRNA expression diminished during PTC tumorigenesis, as AR mRNA expression levels were lower in PTC than normal thyroid tissues from both men and women. AR mRNA expression was significantly decreased in PTC patients with higher risk and in those with extrathyroidal extension. Overexpression of AR in BCPAP cells decreased cell migration and repressed the EMT process by down-regulating mRNA expression of N-cadherin, Snail1, Snail2, Vimentin, and TWIST1 and up-regulating E-cadherin gene expression. These results suggest that suppression of the androgen-AR axis may lead to aggressive tumor behavior in patients with PTC.

Gender differences in thyroid cancer: a critical review

It has long been known that the incidence of thyroid cancer in women is significantly higher than that in men. The objective of this article is to review gender differences in thyroid cancer, as well as epidemiological, clinical and experimental research on the role of sex hormones, their receptors and other molecular factors in this well-established thyroid cancer gender discrepancy. Although more common in women, thyroid cancer typically presents at a more advanced stage and with a worse disease prognosis in men. Clinical evidence on the impact of estrogen and other sex hormones on thyroid cancer has remained inconclusive, although numerous experimental studies have suggested that these hormones and their receptors may play a role in tumorigenesis and tumor progression. Studies of thyroid cancer cell lines suggest that an imbalance between the two estrogen receptor (ER) isoforms, α and β, may be responsible for the cell proliferation seen with estrogen treatment. Expression studies on thyroid tumors indicate that they express ER and possibly progesterone receptors and androgen receptors, but there is conflicting evidence as to whether or not there is a difference in receptor status between thyroid cancers, benign thyroid lesions and normal thyroid tissue. There have been few studies evaluating the ERα/ERβ profiles in thyroid tumors and normal thyroid tissue. Our understanding of the underlying basis for sex differences in thyroid cancer has improved over the last few decades, but the relationship between gender and thyroid cancer risk has remained elusive. Areas for future research include ERα/ERβ profiling of normal and neoplastic thyroid tissue, association between ER status and tumor dedifferentiation, and evaluation of the signaling pathways by which estrogen and other sex steroids exert their effects on thyroid cancer cells. Sex steroid receptors, and then downstream signaling pathways, represent promising future therapeutic targets for thyroid cancer treatment, and further study is required.

Estrogen and progesterone receptors in thyroid lesions

BACKGROUND

Given the higher incidence and better prognosis of thyroid cancers in women, the possibility arises that these lesions may be influenced by sex hormones. With the development of monoclonal antibodies to the estrogen and progesterone receptor proteins, receptor status can now be determined by immunohistochemical methods that allow direct localization of receptors in tissue.

METHODS

Using this technique, we have studied tissues of 11 patients, 2 of them pregnant, with thyroid lesions. Paraffin-embedded tissues were used. Positive controls consisted of known estrogen- and progesterone-positive breast carcinomas.

RESULTS

Examination of both the thyroid lesions and adjacent uninvolved thyroid tissue showed no nuclear reactivity with either estrogen or progesterone receptor antibodies. Our study did not confirm the previously reported incidence of estrogen and progesterone receptors in thyroid lesions.

CONCLUSIONS

We conclude that contrary to earlier indications, estrogen and progesterone receptor proteins are neither significantly detectable nor pertinent for follow-up or prognosis in the patient with thyroid neoplasia.

Hepatic cytosolic oestrogen receptors in patients with liver disease

Patients with liver disease present many of the features of 'feminized' hepatic metabolism. Oestrogens exert their effects through interaction with specific cellular high-affinity receptors (ER). We measured hepatic ER in 102 needle biopsies from patients with chronic alcoholic and non-alcoholic liver disease using an enzyme immunoassay. Fifteen patients with no or minimal changes in liver histology served as controls. The hepatic ER concentrations were significantly (P = 0.05) lower in the 44 men (median 13 fmol mg-1 protein, interquartile range 7-17 fmol mg-1 protein) compared to the 58 women (median 15 fmol mg-1 protein, interquartile range 10-21 fmol mg-1 protein). Patients with alcoholic liver disease (n = 63) had significantly (P < 0.05) lower ER concentrations than controls (n = 15) (median 13 fmol mg-1 protein, interquartile range 7-17 fmol mg-1 protein vs. median 16 fmol mg-1 protein, interquartile range 10-26 fmol mg-1 protein), and compared with patients with non-alcoholic liver disease (n = 24) (P < 0.05, median 20 fmol mg-1 protein, interquartile range 11-24 fmol mg-1 protein). ER concentrations were significantly lower (P < 0.05) in patients with alcoholic liver disease and alcoholic hepatitis (n = 21) compared to those without alcoholic hepatitis (n = 42) (medians 10 vs. 14 fmol mg-1 protein, interquartile ranges 6-15 fmol mg-1 protein vs. 9-18 fmol mg-1 protein), while ER concentrations did not differ significantly (P > 0.05) between actively drinking (median 13 fmol mg-1 protein, interquartile range 7-17 fmol mg-1 protein) and abstaining alcoholic patients (median 13 fmol mg-1 protein. interquartile range 7-18 fmol mg-1 protein). In summary, the small but significant variation in hepatic ER concentrations reflects variation in liver function rather than an effect of ethanol.

Enzyme immunoassay of oestrogen receptors in needle biopsies from human liver

For quantitative assessments of sex hormone receptors in liver tissue, ligand binding assays are inconvenient, as they require large biopsies (0.5-1.0 g). The present study shows that it is possible to measure oestrogen receptors (ER) quantitatively in needle biopsy specimens as small as 10 mg by modifications of a commercial enzyme immunoassay employing monoclonal antibodies. Sucrose gradient centrifugation and the dextran charcoal method served as reference methods. A consecutive series of needle biopsies from patients suspected of liver disease were investigated. The biopsies (n = 37) had a median weight of 14 mg and cytosolic protein concentrations greater than 1 mg/ml (median 1.28 mg/ml). The median ER concentration was 20 fmol/mg cytosolic protein (range 5 to 57 fmol/mg). The intra-assay coefficient of variation was 8.9%, the inter-assay 13.2%, and the detection limit 2.7 fmol/ml cytosol. Women had significantly higher ER concentrations (median 22 fmol/mg) compared to male patients (median 16 fmol/mg) (P = 0.007). The enzyme immunoassay measures ER in liver specimens as small as 10 mg, compared to the large tissue specimens necessary for the conventional DCC assay, and the method is a convenient tool for further studies of ER in routine needle biopsies from the liver.

Relationship between radioligand binding assay, immunoenzyme assay and immunohistochemical assay for estrogen receptors in human breast cancer and association with tumor differentiation

We have studied the merit of a new enzyme immunoassay (EIA) in relation to the results obtained with a conventional dextran-coated charcoal assay (DCC) of estrogen receptors (ER) in cytosols and nuclear extracts of human breast cancer tissue. The results of the two assays were related to cytosolic progesterone receptor content (PgR), semiquantified ER content in formalin-fixed paraffin embedded tissue specimens and tumor differentiation. The EIA was found stable at low cytosol protein concentrations (0.5 mg/ml). The EIA and DCC assays were highly correlated both in cytosols (r = 0.92, n = 57) and nuclear extracts (r = 0.82, n = 25), but the EIA slightly overestimated the ER values in both ER fractions. A significant correlation between ER in nuclear (ER(N] and cytosolic (ER(C] fractions was established with both assays (DCC: r = 0.90, n = 56; EIA: r = 0.83, n = 24). A qualitative relationship was established between PgR and ER fractions as determined with both assays, the best quantitative association was between PgR and ER(N(DCC] (r = 0.58, n = 34, P less than 0.001). A significant qualitative and quantitative relationship was found between semiquantified ER content in formalin-fixed, paraffin-embedded tissue and ER(C(DCC] (r = 0.88), ER(N(DCC] (r = 0.86], ER(C(EIA] (r = 0.60), ER(N(CIA] (r = 0.64) and PgR (r = 0.65). Finally, we found tumor differentiation to be significantly associated with ER content as determined with all assays except for ER(N(EIA]. We recommend the use of the DCC assay for routine analysis of ER until the clinical correlation of EIA results has been established.

Gynecomasty: estrogen and androgen receptors. A clinical-pathological investigation

The histology, estrogen (ER)- and androgen (AR)- receptor content, s-FSH, s-LH, s-17-beta-estradiol, U-17-ketosteroid and U-17-ketogenic steroid patterns were measured in a consecutive series of 20 patients operated on for gynecomasty. Two out of 22 specimens were ER-positive, and 4 out of 22 were AR-positive. No relationship was demonstrated between the histopathologic features, ie. active-intermediate-inactive gynecomasty, and the steroid receptor content in the present limited number of cases. In addition, there was no marked relationship between the histopathologic features and the hormone values.

Bone mineral content and estrogen receptors in women with breast tumors

The investigation was carried out to elucidate a possible relationship between the amount of estrogen receptors and bone mineral content in patients with breast tumors. Bone mineral content (BMC) was measured by photon absorptiometry in the distal forearm of 54 women with untreated breast carcinoma and 19 with benign breast tumor. The concentration of unoccupied high affinity estrogen receptors was measured in breast tumor biopsy specimens. Higher values of BMC were found in the total group of estrogen receptor-positive patients with breast carcinoma compared with estrogen receptor-negative patients, but not after dividing the patients into smaller groups according to age. No significant correlation could be seen between the amount of estrogen receptors and bone mineral content. In conclusion the present study could not support a relationship between the amount of estrogen receptors in breast cancer tissue and the amount of bone mineral and bone mass in women with breast tumors.

Ploidy level of human breast carcinoma. Relation to histopathologic features and hormone receptor content

The ploidy level was investigated by flow cytometric analysis in 143 cases of invasive intraductal mammary carcinoma. Aneuploidy was found in 70% of the tumours. Comparison of ploidy level with histopathologic features, hormone receptor status and clinical characteristics indicated that aneuploid tumours were mostly poorly differentiated (grade III) and oestrogen receptor negative (p less than 0.05). However, this applied only to postmenopausal patients. No correlation appeared between the progesterone receptor status and the ploidy level, but this parameter tended to predict the frequency of lymph node metastases. The possible prognostic significance of these findings is discussed.