So over the past little while on the board I have been reading various members mention that they suffered from sore nipples and gyno symptoms when using HCG and blamed this on elevated estrogen levels due to the Human Chorionic Gonadotropin (HCG). This always bugged me as I remembered reading a study that suggested another possible explanation for the sensitivity. Well I finally found the study. I hope some of you find it useful/interesting.
____________________________________________________________
Presence of Luteinizing Hormone/Human Chorionic Gonadotropin Receptors in Male Breast Tissues
Harold E. Carlson, Philip Kane, Z. M. Lei, X. Li and C. V. Rao
Departments of Medicine (H.E.C.) and Pathology (P.K.), Stony Brook University, Stony Brook, New York 11794; and Department of Obstetrics, Gynecology and Women’s Health (Z.M.L., X.L., C.V.R.), University of Louisville, Louisville, Kentucky 40292
Abstract
Receptors for LH/human chorionic gonadotropin (hCG) have been found in a variety of nongonadal tissues including the female breast. Using in situ hybridization and immunohistochemistry, we demonstrated the presence of LH/hCG receptor mRNA and protein in normal male breast tissue obtained at autopsy (n = 4) and archival samples of benign gynecomastia (n = 14) and male breast carcinoma (n = 5). Although the function of these receptors remains to be determined, the findings suggest the possibility that LH and hCG may play a role in the pathogenesis of male breast disorders.
Introduction
ALTHOUGH RECEPTORS FOR LH/human chorionic gonadotropin (hCG) have traditionally been associated with gonadal tissues, recent studies have documented the presence of functional LH/hCG receptors in a variety of nongonadal organs including the adrenal, uterus, fallopian tubes, placenta, brain, retina, skin, bone, prostate, seminal vesicle, and female breast (1). In the human female, LH/hCG receptors were detected in epithelial cells in normal breast tissue, benign breast lesions, breast carcinoma tissue, and breast cancer cell lines (2, 3). Depending on the culture conditions, hCG exerts either a stimulatory or an inhibitory effect on the growth of female human breast cell lines (3, 4, 5). We therefore wished to determine whether human male breast tissue also expresses the LH/hCG receptor.
Materials and Methods
Tissue samples
Formalin-fixed, paraffin-embedded male breast tissues were obtained through the Department of Pathology at University Hospital-Stony Brook and the University of Louisville. Breast tissue was collected from four men at autopsy (ages 25–73 yr); none of these men was known to have breast disease antemortem. Fourteen archived breast tissue specimens were studied from 13 men, ages 15–78 yr, who underwent surgical excision of benign gynecomastia; bilateral specimens were obtained from one man. Table 1 presents the ages of the gynecomastia patients and the presumed causes of their breast enlargement. Archived breast tissue specimens were studied from five men, ages 49–69 yr, with breast carcinoma. The study was approved by the institutional review boards at Stony Brook University and the University of Louisville.
In situ hybridization (ISH)
For ISH, the sections were treated for 30 min at 37 C with 60 mM Tris-HCl, pH 7.5, containing 5 µg/ml proteinase K and 5 mM EDTA. The sections were then prehybridized in moist chambers for 3 h at 55 C with a mixture containing 50% formamide, 5x sodium chloride/sodium citrate (SSC), 1x Denhardt’s solution, 1 mg/ml yeast tRNA, 100 µg/ml heparin, and 5 mM EDTA. Hybridization was then performed in the same reaction mixture containing fluorescein-uridine triphosphate-labeled riboprobes transcribed from human LH/hCG receptor cDNA, obtained from Dr. Aaron J. W. Hsueh at Stanford University School of Medicine (Palo Alto, CA). Hybridization with sense probe under identical conditions served as a procedural control. After hybridization, the slides were washed twice with 1x SSC and then with 2x SSC for 15 min each, and then twice with 0.2x SSC for 30 min each time at 55 C. Hybridization signals were detected using an antifluorescein alkaline phosphatase conjugate and 5-nitroblue tetrazolium/5-bromo-4-chloro-3-indolylphosphate, which gave a blue color.
Immunohistochemistry (IHC)
IHC was performed by an avidin immunoperoxidase method using a polyclonal LH/hCG receptor antibody raised against a synthetic N terminus amino acid sequence of 15–38 (a gift from Dr. Patrick Roche, who is now at Ventana Medical Systems, Tucson, AZ). The sections were incubated overnight at 4 C with a 1:350 dilution of the receptor antibody. For the procedural control, the receptor antibody was preabsorbed with excess receptor peptide.
Histological scoring and statistics
Microscopically determined relative IHC and ISH scores were visually estimated on several high-power microscopic fields for three different sections from each tissue block. Each specimen was given a score from 0 (no staining) to 4 (most intense staining) based on the average signal intensity in the epithelial cells. Although these are subjective scores, we are cautious about objectively scoring the signal intensities in the entire area of three different sections from each tissue block. The mean IHC and ISH scores for each specimen category were analyzed by one-way ANOVA and Dunnett’s multiple comparison test.
Slides from gynecomastia specimens were also stained with hematoxylin and eosin; the degree of epithelial proliferation, periductal round cell infiltrate, and duct epithelial atypia was scored on a scale of 1 (minimal) to 3 (marked).
Linear regression analysis was used to examine possible correlations between the IHC and ISH scores in the entire group of 23 breast tissue specimens. The same linear regression analysis was used to determine whether IHC or ISH scores correlated with scores for epithelial proliferation, periductal round cell infiltrate, or duct epithelial atypia in the gynecomastia specimens.
Results
On routine hematoxylin and eosin staining (Fig. 1), normal male breast tissue obtained at autopsy showed a few ductules, whereas breast tissue removed from patients with gynecomastia or breast cancer showed features typical of those conditions.
ISH analysis revealed the presence of hybridization signals for human LH/hCG receptor mRNA in normal, gynecomastia, and cancer specimens. These signals were abundant in epithelial elements (Fig. 2). Signal intensity appeared more intense in breast cancer specimens than in normal male breast or gynecomastia samples. As expected, the procedural control using sense probe showed no hybridization signals (Fig. 2E). There was a trend toward higher mean ISH scores in the gynecomastia and cancer specimens than in the normal male breast tissues (Table 1), although this did not reach statistical significance.
IHC revealed the presence of receptor immunostaining in all specimens (Fig. 3). As with ISH, receptor immunostaining was particularly abundant in epithelial cells. There was no staining following preabsorption of the antibody with excess receptor peptide (Fig. 3E). As with ISH, there was a nonsignificant trend toward higher mean IHC scores in the gynecomastia and cancer specimens than in the normal male breast tissues (Table 1). IHC scores were significantly correlated with ISH scores over the entire sample (n = 23), with r = 0.51; P < 0.05.
Examination of hematoxylin- and eosin-stained sections of gynecomastia tissues revealed variable degrees of epithelial proliferation, periductal round cell infiltrate, and duct epithelial hyperplasia. None of these features were significantly correlated with either ISH results or immunohistochemical demonstration of the LH/hCG receptor protein (Table 1).
Discussion
To our knowledge, this is the first study to demonstrate the presence of LH/hCG receptor mRNA and protein in normal male breast tissue as well as in a variety of benign and malignant human male breast disorders. These results parallel previous demonstrations of LH/hCG receptors in analogous female breast tissues (1, 2). In cultured female human breast epithelial cells, LH/hCG signaling exerts an antiproliferative effect under some culture conditions, decreases the expression of estrogen receptors, and activates apoptotic gene expression (2, 3, 4). However, in cultured MCF-7 human breast cancer cells, hCG has also been reported to stimulate cell growth by promoting intracellular conversion of androgens to estrogens (5). Thus, the actions of hCG on the female breast appear to be complex.
The normal male breast specimens obtained at autopsy were selected for further study because ductules could be demonstrated on routine histological examination. Thus, it is possible that the normal male breasts examined in this study may actually have come from men with mild, undiagnosed gynecomastia. Older series reported a 40–55% prevalence of histological gynecomastia in males at autopsy (6, 7); similarly, careful breast examination has revealed the presence of palpable breast tissue in 30–70% of normal men, with the highest prevalence being seen in older age groups (8, 9). Nevertheless, it may be argued that these men with palpable breast tissue are still typical of the normal male population.
At present, the functions of LH/hCG receptors in the male breast remain unknown. It is possible, however, that they may be involved in the pathogenesis of gynecomastia or male breast cancer growth. Gynecomastia is common among men with testicular failure, a state associated with elevated serum LH levels, and in patients with hCG-secreting neoplasms (10, 11); although gynecomastia is usually attributed to an estrogen/androgen imbalance occurring under these conditions, it may also be due, in part, to a more direct action of LH or hCG on the male breast. In addition, it has been suggested that endogenous gonadotropins may play a direct stimulatory role in the growth of the normal female breast (12), which makes it possible that a similar phenomenon may occur in males. Finally, hCG and its subunits appear to be produced by normal and, particularly, malignant female breast epithelial cells (13, 14, 15), raising the possibility of an autocrine or paracrine action within the breast itself. The mechanism of such a direct action on the breast is unclear; however, it has been reported that LH and hCG modestly decrease both androgen receptor protein and type 2 5-reductase protein in skin appendages (16). If also present in the breast, such an effect would decrease the inhibitory effects of androgen on epithelial proliferation (17) and could conceivably contribute to the development of gynecomastia or breast cancer.
In summary, normal male breast tissue and archival samples of gynecomastia and male breast cancer contain LH/hCG receptor mRNA transcripts and protein. These findings lay groundwork for further studies on the role of LH and hCG in the pathophysiology of male breast disorders.
Acknowledgments
We thank Gabor Ambrus, M.D. (Department of Pathology, University of Louisville), for collecting one normal male breast tissue autopsy specimen.
Footnotes
Abbreviations: hCG, Human chorionic gonadotropin; IHC, immunohistochemistry; ISH, in situ hybridization; SSC, sodium chloride/sodium citrate.
Received October 29, 2003.
Accepted April 25, 2004.
References
1. Rao CV 2001 Multiple novel roles of luteinizing hormone. Fertil Steril 76:1097–1100[CrossRef][Medline]
2. Meduri G, Charnaux N, Loosfelt H, Jolivet A, Spyratos F, Brailly S, Milgrom E 1997 Luteinizing hormone/human chorionic gonadotropin receptors in breast cancer. Cancer Res 57:857–864[Abstract]
3. Lojun S, Bao S, Lei ZM, Rao CV 1997 Presence of functional luteinizing hormone/chorionic gonadotropin (hCG) receptors in human breast cell lines: implications supporting the premise that hCG protects women against breast cancer. Biol Reprod 57:1202–1210[Abstract]
4. Srivastava P, Russo J, Mgbonyebi OP, Russo IH 1998 Growth inhibition and activation of apoptotic gene expression by human chorionic gonadotropin in human breast epithelial cells. Anticancer Res 18:4003–4010[Medline]
5. Tanaka Y, Kuwabara K, Okazaki T, Fujita T, Oizumi I, Kaiho S, Ogata E 2000 Gonadotropins stimulate growth of MCF-7 human breast cancer cells by promoting intracellular conversion of adrenal androgens to estrogens. Oncology 59(Suppl 1):19–23
6. Williams MJ 1963 Gynecomastia. Its incidence, recognition and host characterization in 447 autopsy cases. Am J Med 34:103–112
7. Andersen JA, Gram JB 1982 Male breast at autopsy. Acta Pathol Microbiol Immunol Scand [A] 90:191–197[Medline]
8. Nuttall FQ 1979 Gynecomastia as a physical finding in normal men. J Clin Endocrinol Metab 48:338–340[Abstract]
9. Niewoehner CB, Nuttall FQ 1984 Gynecomastia in a hospitalized male population. Am J Med 77:633–638[Medline]
10. Braunstein GD 1993 Gynecomastia. N Engl J Med 328:490–495[Free Full Text]
11. Hershkovitz E, Leiberman E 2002 Gynecomastia: a review. Endocrinologist 12:321–332
12. Pertzelan A, Yalon L, Kauli R, Laron Z 1982 A comparative study of the effect of oestrogen substitution therapy on breast development in girls with hypo- and hypergonadotrophic hypogonadism. Clin Endocrinol (Oxf) 16:359–368[Medline]
13. Abney TO, Teran A-Z, Mahesh VB, Mullins WB, Greenblatt RB 1988 Fibrocystic breast disease: the significance of ß-human chorionic gonadotropin and other polypeptides in breast cyst fluid. Fertil Steril 49:638–643[Medline]
14. Reimer T, Koczan D, Muller H, Friese K, Krause A, Thiesen HJ, Gerber B 2000 Human chorionic gonadotrophin-ß transcripts correlate with progesterone receptor values in breast carcinomas. J Mol Endocrinol 24:33–41[Abstract/Free Full Text]
15. Taback B, Chan AD, Kuo CT, Bostick PJ, Wang H-J, Giuliano AE, Hoon DSB 2001 Detection of occult metastatic breast cancer cells in blood by a multimolecular marker assay: correlation with clinical stage of disease. Cancer Res 61:8845–8850[Abstract/Free Full Text]
16. Bird J, Li X, Lei ZM, Sanfilippo J, Yussman MA, Rao CV 1998 Luteinizing hormone and human chorionic gonadotropin decrease type 2 5-reductase and androgen receptor protein levels in women’s skin. J Clin Endocrinol Metab 83:1776–1782[Abstract/Free Full Text]
17. Dimitrakakis C, Zhou J, Bondy CA 2002 Androgens and mammary growth and neoplasia. Fertil Steril 77(Suppl 4):S26–S33
____________________________________________________________
Presence of Luteinizing Hormone/Human Chorionic Gonadotropin Receptors in Male Breast Tissues
Harold E. Carlson, Philip Kane, Z. M. Lei, X. Li and C. V. Rao
Departments of Medicine (H.E.C.) and Pathology (P.K.), Stony Brook University, Stony Brook, New York 11794; and Department of Obstetrics, Gynecology and Women’s Health (Z.M.L., X.L., C.V.R.), University of Louisville, Louisville, Kentucky 40292
Abstract
Receptors for LH/human chorionic gonadotropin (hCG) have been found in a variety of nongonadal tissues including the female breast. Using in situ hybridization and immunohistochemistry, we demonstrated the presence of LH/hCG receptor mRNA and protein in normal male breast tissue obtained at autopsy (n = 4) and archival samples of benign gynecomastia (n = 14) and male breast carcinoma (n = 5). Although the function of these receptors remains to be determined, the findings suggest the possibility that LH and hCG may play a role in the pathogenesis of male breast disorders.
Introduction
ALTHOUGH RECEPTORS FOR LH/human chorionic gonadotropin (hCG) have traditionally been associated with gonadal tissues, recent studies have documented the presence of functional LH/hCG receptors in a variety of nongonadal organs including the adrenal, uterus, fallopian tubes, placenta, brain, retina, skin, bone, prostate, seminal vesicle, and female breast (1). In the human female, LH/hCG receptors were detected in epithelial cells in normal breast tissue, benign breast lesions, breast carcinoma tissue, and breast cancer cell lines (2, 3). Depending on the culture conditions, hCG exerts either a stimulatory or an inhibitory effect on the growth of female human breast cell lines (3, 4, 5). We therefore wished to determine whether human male breast tissue also expresses the LH/hCG receptor.
Materials and Methods
Tissue samples
Formalin-fixed, paraffin-embedded male breast tissues were obtained through the Department of Pathology at University Hospital-Stony Brook and the University of Louisville. Breast tissue was collected from four men at autopsy (ages 25–73 yr); none of these men was known to have breast disease antemortem. Fourteen archived breast tissue specimens were studied from 13 men, ages 15–78 yr, who underwent surgical excision of benign gynecomastia; bilateral specimens were obtained from one man. Table 1 presents the ages of the gynecomastia patients and the presumed causes of their breast enlargement. Archived breast tissue specimens were studied from five men, ages 49–69 yr, with breast carcinoma. The study was approved by the institutional review boards at Stony Brook University and the University of Louisville.
In situ hybridization (ISH)
For ISH, the sections were treated for 30 min at 37 C with 60 mM Tris-HCl, pH 7.5, containing 5 µg/ml proteinase K and 5 mM EDTA. The sections were then prehybridized in moist chambers for 3 h at 55 C with a mixture containing 50% formamide, 5x sodium chloride/sodium citrate (SSC), 1x Denhardt’s solution, 1 mg/ml yeast tRNA, 100 µg/ml heparin, and 5 mM EDTA. Hybridization was then performed in the same reaction mixture containing fluorescein-uridine triphosphate-labeled riboprobes transcribed from human LH/hCG receptor cDNA, obtained from Dr. Aaron J. W. Hsueh at Stanford University School of Medicine (Palo Alto, CA). Hybridization with sense probe under identical conditions served as a procedural control. After hybridization, the slides were washed twice with 1x SSC and then with 2x SSC for 15 min each, and then twice with 0.2x SSC for 30 min each time at 55 C. Hybridization signals were detected using an antifluorescein alkaline phosphatase conjugate and 5-nitroblue tetrazolium/5-bromo-4-chloro-3-indolylphosphate, which gave a blue color.
Immunohistochemistry (IHC)
IHC was performed by an avidin immunoperoxidase method using a polyclonal LH/hCG receptor antibody raised against a synthetic N terminus amino acid sequence of 15–38 (a gift from Dr. Patrick Roche, who is now at Ventana Medical Systems, Tucson, AZ). The sections were incubated overnight at 4 C with a 1:350 dilution of the receptor antibody. For the procedural control, the receptor antibody was preabsorbed with excess receptor peptide.
Histological scoring and statistics
Microscopically determined relative IHC and ISH scores were visually estimated on several high-power microscopic fields for three different sections from each tissue block. Each specimen was given a score from 0 (no staining) to 4 (most intense staining) based on the average signal intensity in the epithelial cells. Although these are subjective scores, we are cautious about objectively scoring the signal intensities in the entire area of three different sections from each tissue block. The mean IHC and ISH scores for each specimen category were analyzed by one-way ANOVA and Dunnett’s multiple comparison test.
Slides from gynecomastia specimens were also stained with hematoxylin and eosin; the degree of epithelial proliferation, periductal round cell infiltrate, and duct epithelial atypia was scored on a scale of 1 (minimal) to 3 (marked).
Linear regression analysis was used to examine possible correlations between the IHC and ISH scores in the entire group of 23 breast tissue specimens. The same linear regression analysis was used to determine whether IHC or ISH scores correlated with scores for epithelial proliferation, periductal round cell infiltrate, or duct epithelial atypia in the gynecomastia specimens.
Results
On routine hematoxylin and eosin staining (Fig. 1), normal male breast tissue obtained at autopsy showed a few ductules, whereas breast tissue removed from patients with gynecomastia or breast cancer showed features typical of those conditions.
ISH analysis revealed the presence of hybridization signals for human LH/hCG receptor mRNA in normal, gynecomastia, and cancer specimens. These signals were abundant in epithelial elements (Fig. 2). Signal intensity appeared more intense in breast cancer specimens than in normal male breast or gynecomastia samples. As expected, the procedural control using sense probe showed no hybridization signals (Fig. 2E). There was a trend toward higher mean ISH scores in the gynecomastia and cancer specimens than in the normal male breast tissues (Table 1), although this did not reach statistical significance.
IHC revealed the presence of receptor immunostaining in all specimens (Fig. 3). As with ISH, receptor immunostaining was particularly abundant in epithelial cells. There was no staining following preabsorption of the antibody with excess receptor peptide (Fig. 3E). As with ISH, there was a nonsignificant trend toward higher mean IHC scores in the gynecomastia and cancer specimens than in the normal male breast tissues (Table 1). IHC scores were significantly correlated with ISH scores over the entire sample (n = 23), with r = 0.51; P < 0.05.
Examination of hematoxylin- and eosin-stained sections of gynecomastia tissues revealed variable degrees of epithelial proliferation, periductal round cell infiltrate, and duct epithelial hyperplasia. None of these features were significantly correlated with either ISH results or immunohistochemical demonstration of the LH/hCG receptor protein (Table 1).
Discussion
To our knowledge, this is the first study to demonstrate the presence of LH/hCG receptor mRNA and protein in normal male breast tissue as well as in a variety of benign and malignant human male breast disorders. These results parallel previous demonstrations of LH/hCG receptors in analogous female breast tissues (1, 2). In cultured female human breast epithelial cells, LH/hCG signaling exerts an antiproliferative effect under some culture conditions, decreases the expression of estrogen receptors, and activates apoptotic gene expression (2, 3, 4). However, in cultured MCF-7 human breast cancer cells, hCG has also been reported to stimulate cell growth by promoting intracellular conversion of androgens to estrogens (5). Thus, the actions of hCG on the female breast appear to be complex.
The normal male breast specimens obtained at autopsy were selected for further study because ductules could be demonstrated on routine histological examination. Thus, it is possible that the normal male breasts examined in this study may actually have come from men with mild, undiagnosed gynecomastia. Older series reported a 40–55% prevalence of histological gynecomastia in males at autopsy (6, 7); similarly, careful breast examination has revealed the presence of palpable breast tissue in 30–70% of normal men, with the highest prevalence being seen in older age groups (8, 9). Nevertheless, it may be argued that these men with palpable breast tissue are still typical of the normal male population.
At present, the functions of LH/hCG receptors in the male breast remain unknown. It is possible, however, that they may be involved in the pathogenesis of gynecomastia or male breast cancer growth. Gynecomastia is common among men with testicular failure, a state associated with elevated serum LH levels, and in patients with hCG-secreting neoplasms (10, 11); although gynecomastia is usually attributed to an estrogen/androgen imbalance occurring under these conditions, it may also be due, in part, to a more direct action of LH or hCG on the male breast. In addition, it has been suggested that endogenous gonadotropins may play a direct stimulatory role in the growth of the normal female breast (12), which makes it possible that a similar phenomenon may occur in males. Finally, hCG and its subunits appear to be produced by normal and, particularly, malignant female breast epithelial cells (13, 14, 15), raising the possibility of an autocrine or paracrine action within the breast itself. The mechanism of such a direct action on the breast is unclear; however, it has been reported that LH and hCG modestly decrease both androgen receptor protein and type 2 5-reductase protein in skin appendages (16). If also present in the breast, such an effect would decrease the inhibitory effects of androgen on epithelial proliferation (17) and could conceivably contribute to the development of gynecomastia or breast cancer.
In summary, normal male breast tissue and archival samples of gynecomastia and male breast cancer contain LH/hCG receptor mRNA transcripts and protein. These findings lay groundwork for further studies on the role of LH and hCG in the pathophysiology of male breast disorders.
Acknowledgments
We thank Gabor Ambrus, M.D. (Department of Pathology, University of Louisville), for collecting one normal male breast tissue autopsy specimen.
Footnotes
Abbreviations: hCG, Human chorionic gonadotropin; IHC, immunohistochemistry; ISH, in situ hybridization; SSC, sodium chloride/sodium citrate.
Received October 29, 2003.
Accepted April 25, 2004.
References
1. Rao CV 2001 Multiple novel roles of luteinizing hormone. Fertil Steril 76:1097–1100[CrossRef][Medline]
2. Meduri G, Charnaux N, Loosfelt H, Jolivet A, Spyratos F, Brailly S, Milgrom E 1997 Luteinizing hormone/human chorionic gonadotropin receptors in breast cancer. Cancer Res 57:857–864[Abstract]
3. Lojun S, Bao S, Lei ZM, Rao CV 1997 Presence of functional luteinizing hormone/chorionic gonadotropin (hCG) receptors in human breast cell lines: implications supporting the premise that hCG protects women against breast cancer. Biol Reprod 57:1202–1210[Abstract]
4. Srivastava P, Russo J, Mgbonyebi OP, Russo IH 1998 Growth inhibition and activation of apoptotic gene expression by human chorionic gonadotropin in human breast epithelial cells. Anticancer Res 18:4003–4010[Medline]
5. Tanaka Y, Kuwabara K, Okazaki T, Fujita T, Oizumi I, Kaiho S, Ogata E 2000 Gonadotropins stimulate growth of MCF-7 human breast cancer cells by promoting intracellular conversion of adrenal androgens to estrogens. Oncology 59(Suppl 1):19–23
6. Williams MJ 1963 Gynecomastia. Its incidence, recognition and host characterization in 447 autopsy cases. Am J Med 34:103–112
7. Andersen JA, Gram JB 1982 Male breast at autopsy. Acta Pathol Microbiol Immunol Scand [A] 90:191–197[Medline]
8. Nuttall FQ 1979 Gynecomastia as a physical finding in normal men. J Clin Endocrinol Metab 48:338–340[Abstract]
9. Niewoehner CB, Nuttall FQ 1984 Gynecomastia in a hospitalized male population. Am J Med 77:633–638[Medline]
10. Braunstein GD 1993 Gynecomastia. N Engl J Med 328:490–495[Free Full Text]
11. Hershkovitz E, Leiberman E 2002 Gynecomastia: a review. Endocrinologist 12:321–332
12. Pertzelan A, Yalon L, Kauli R, Laron Z 1982 A comparative study of the effect of oestrogen substitution therapy on breast development in girls with hypo- and hypergonadotrophic hypogonadism. Clin Endocrinol (Oxf) 16:359–368[Medline]
13. Abney TO, Teran A-Z, Mahesh VB, Mullins WB, Greenblatt RB 1988 Fibrocystic breast disease: the significance of ß-human chorionic gonadotropin and other polypeptides in breast cyst fluid. Fertil Steril 49:638–643[Medline]
14. Reimer T, Koczan D, Muller H, Friese K, Krause A, Thiesen HJ, Gerber B 2000 Human chorionic gonadotrophin-ß transcripts correlate with progesterone receptor values in breast carcinomas. J Mol Endocrinol 24:33–41[Abstract/Free Full Text]
15. Taback B, Chan AD, Kuo CT, Bostick PJ, Wang H-J, Giuliano AE, Hoon DSB 2001 Detection of occult metastatic breast cancer cells in blood by a multimolecular marker assay: correlation with clinical stage of disease. Cancer Res 61:8845–8850[Abstract/Free Full Text]
16. Bird J, Li X, Lei ZM, Sanfilippo J, Yussman MA, Rao CV 1998 Luteinizing hormone and human chorionic gonadotropin decrease type 2 5-reductase and androgen receptor protein levels in women’s skin. J Clin Endocrinol Metab 83:1776–1782[Abstract/Free Full Text]
17. Dimitrakakis C, Zhou J, Bondy CA 2002 Androgens and mammary growth and neoplasia. Fertil Steril 77(Suppl 4):S26–S33
