Androgens and breast cancer in men and women

Incidence of prostate, colorectal and male breast cancers in relation with statins and testosterone replacement therapy: SEER-Medicare 2007-2015

INTRODUCTION

Statins and testosterone replacement therapy (TTh) have been inconsistently associated with a reduced risk of hormone-related cancers (HRCs, prostate [PCa], colorectal [CRC], and male breast cancers [BrCa]). Yet, the joint association of statins and TTh with the incidence of these cancers, and whether these associations vary by race, remains poorly understood. The objective of this retrospective cohort study is to examine the independent and joint effects of pre-diagnostic use of statins and TTh on the risk of HRCs, including PCa, CRC, and male BrCa.

MATERIALS

and Methods: In 105,690 men (≥65 yrs) identified using the SEER-Medicare 2007-2015 data, we identified 82,578 White and 10,256 Black men. Pre-diagnostic prescription of statins and TTh was ascertained for this analysis and categorized into four groups (Neither users, statins alone, TTh alone and Dual users). Multivariable Time-varying Cox proportional hazards and Accelerated Failure Time (AFT) models were performed.

RESULTS

We found inverse joint associations of statins and TTh with incident HRCs before (aHR: 0.39; 95 % CI: 0.35-0.44) and after 3 years of follow-up (aHR: 0.74; 95 % CI: 0.67-0.82). This included a lower risk for advanced stage HRC (only <3 years follow-up). Similar joint associations were identified with incident PCa, aggressive PCa, incident CRC, and its specific right- and left-sided CRC (only <3 years follow-up). In general, the inverse associations persisted among White (mainly <3 years follow-up) and Black men (high-grade HRC and <3 years follow-up). Findings from the AFT analysis were similar.

DISCUSSION

Pre-diagnostic use of statins and TTh were, independently and jointly, associated with reduced risks of HRC and specific cancer sites at three years of follow-up overall, and among White and Black men. Greatest associations of HRCs risk reduction were observed among dual users (statins plus TTh). Further studies are needed to validate these findings, including larger samples of Black men, and male BrCa sites.

Effect of statins and testosterone replacement therapy on incident cardiovascular disease among male hormone-related cancer survivors

Purpose

Statins and testosterone replacement therapy (TTh) have been previously linked with prostate, colorectal and male breast cancer (hereinafter we will refer as hormone related cancers [HRCa]), and cardiovascular disease (CVD). However, there is a poor understanding about the combined association of statins and TTh with incident CVD among HRCa survivors and a matched cancer-free cohort.

Methods

We identified 44,330 men of whom 22,165 were previously diagnosed with HRCa, and 22,165 were age-and index-matched cancer-free in SEER-Medicare 2007-2015. Pre-diagnostic prescription of statins and TTh prior to CVD development was ascertained for this analysis in the two matched cohorts. Weighted multivariable-adjusted conditional logistic regression models were used to evaluate the independent and combined associations of statins and TTh with CVD.

Results

We found that use of statins (OR = 0.51, 95% CI: 0.46-0.55) and TTh (OR = 0.81, 95% CI: 0.67-0.97) were each independently inversely associated with incident CVD in the overall sample. TTh plus statins was also inversely associated with CVD. Associations were similar in the matched cancer-free cohort. Among HRCa survivors, only statins and combination of TTh plus statins (OR = 0.60, 95% CI: 0.44-0.98) were inversely associated with CVD, but the independent use of TTh was not associated with CVD.

Conclusion

In general, pre-diagnostic use of statins and TTh, prior to CVD development, independently or in combination, were inversely associated with CVD in the overall, cancer-free population, and among HRCa survivors (mainly combination). Independent effects and combination of statins and TTh remained to be confirmed with specific CVD outcomes among HRCa survivors.

Natural products derived from medicinal plants and microbes might act as a game-changer in breast cancer: a comprehensive review of preclinical and clinical studies

Breast cancer (BC) is the most prevalent neoplasm among women. Genetic and environmental factors lead to BC development and on this basis, several preventive - screening and therapeutic interventions have been developed. Hormones, both in the form of endogenous hormonal signaling or hormonal contraceptives, play an important role in BC pathogenesis and progression. On top of these, breast microbiota includes both species with an immunomodulatory activity enhancing the host's response against cancer cells and species producing proinflammatory cytokines associated with BC development. Identification of novel multitargeted therapeutic agents with poly-pharmacological potential is a dire need to combat advanced and metastatic BC. A growing body of research has emphasized the potential of natural compounds derived from medicinal plants and microbial species as complementary BC treatment regimens, including dietary supplements and probiotics. In particular, extracts from plants such as Artemisia monosperma Delile, Origanum dayi Post, Urtica membranacea Poir. ex Savigny, Krameria lappacea (Dombey) Burdet & B.B. Simpson and metabolites extracted from microbes such as Deinococcus radiodurans and Streptomycetes strains as well as probiotics like Bacillus coagulans and Lactobacillus brevis MK05 have exhibited antitumor effects in the form of antiproliferative and cytotoxic activity, increase in tumors' chemosensitivity, antioxidant activity and modulation of BC - associated molecular pathways. Further, bioactive compounds like 3,3'-diindolylmethane, epigallocatechin gallate, genistein, rutin, resveratrol, lycopene, sulforaphane, silibinin, rosmarinic acid, and shikonin are of special interest for the researchers and clinicians because these natural agents have multimodal action and act via multiple ways in managing the BC and most of these agents are regularly available in our food and fruit diets. Evidence from clinical trials suggests that such products had major potential in enhancing the effectiveness of conventional antitumor agents and decreasing their side effects. We here provide a comprehensive review of the therapeutic effects and mechanistic underpinnings of medicinal plants and microbial metabolites in BC management. The future perspectives on the translation of these findings to the personalized treatment of BC are provided and discussed.

Use of weight loss medications in relation with prostate, colorectal and male breast cancers among older men: SEER-Medicare 2007-2015

BACKGROUND

The association of weight loss medications with prostate (PCa), colorectal (CRC) or male breast cancers, including assessment of these cancers combined (HRCs, hormone-associated cancers) remain poorly understood. Testosterone replacement therapy (TTh) is reported to be inversely associated with obesity, PCa and CRC, but it is unclear whether TTh modifies the association of weight loss medications with HRCs.

METHODS

In 49,038 men (≥ 65 years) of SEER-Medicare, we identified 15,471 men diagnosed with PCa, 4836 with CRC, and 141 with male breast cancers. Pre-diagnostic prescription of weight loss medications and TTh was ascertained for this analysis. Weighted multivariable-adjusted conditional logistic and Cox proportional hazards (mortality) models were conducted.

RESULTS

We found an inverse association between use of weight loss medications and incident PCa (OR 0.59, 95% CI 0.57-0.62), CRC (OR 0.86, 95% CI 0.80-0.92), and HRCs (OR 0.65, 95% CI 0.62-0.68). Similar associations were observed for advanced stage at diagnosis of PCa and CRC. Effects of weight loss medications on PCa and HRC remained significant irrespective of the use of TTh but were only suggestive with CRC with positive TTh use. No associations were observed with male breast cancer and HRCs mortality.

CONCLUSION

Pre-diagnostic use of weight loss medications reduced the incidence of PCa, CRC, and HRCs. These associations persisted in the same direction irrespective of the history of TTh use. Future studies are needed to confirm these findings and to identify underlying biological mechanisms of weight loss medications and TTh on the risk of cancer.

Metformin and testosterone replacement therapy inversely associated with hormone-associated cancers (prostate, colorectal and male breast cancers) among older White and Black men

BACKGROUND

The independent and joint association of metformin and testosterone replacement therapy (TTh) with the incidence of prostate, colorectal, and male breast cancers remain poorly understood, including the investigation of the risk of these cancers combined (HRCs, hormone-associated cancers) among men of different racial and ethnic background.

METHODS

In 143,035 men (≥ 65 yrs old) of SEER-Medicare 2007-2015, we identified White (N = 110,430), Black (N = 13,520) and Other Race (N = 19,085) men diagnosed with incident HRC. Pre-diagnostic prescription of metformin and TTh was ascertained for this analysis. Weighted multivariable-adjusted conditional logistic and Cox proportional hazards models were conducted.

RESULTS

We found independent and joint associations of metformin and TTh with incident prostate (odds ratio [OR]joint  = 0.44, 95% confidence interval [CI]: 0.36-0.54) and colorectal cancers (ORjoint  = 0.47, 95% CI: 0.34-0.64), but not with male breast cancer. There were also inversed joint associations of metformin and TTh with HRCs (ORjoint  = 0.45, 95% CI: 0.38-0.54). Similar reduced associations with HRCs were identified among White, Black, and Other Race men.

CONCLUSION

Pre-diagnostic use of metformin and TTh were, independently and jointly, inversely associated with incident prostate and colorectal cancers. The risk of HRCs was also reduced among White, Black and Other Race men. Greatest reduced associations of prostate and colorectal cancers and HRCs were mainly observed in combination of metformin and TTh. Larger studies are needed to confirm the independent and joint association of metformin plus TTh with these cancers in understudied and underserved populations.

Breast Cancer Incidence Reduction in Women Treated with Subcutaneous Testosterone: Testosterone Therapy and Breast Cancer Incidence Study

Objective

Testosterone (T) therapy has been shown to be breast protective in both pre- and post-menopausal patients. Additionally, estradiol (E) does not cause breast cancer (BC) in the majority of the world's literatures. This study aimed to investigate the incidence of invasive BC (IBC) in pre- and postmenopausal women treated with T therapy and T in combination with E (T/E).

Materials and Methods

Since January 2010, a total of 2,377 pre- and post-menopausal women were treated with T or T/E implants. IBC rates were reported based on newly diagnosed IBC cases in the total study. Total cases divided by the total sample size and years in study was expressed as an incidence per 100,000 person-years (P-Ys). The BC incidence was compared with age-specific Surveillance Epidemiology and End Results (SEER) incidence rates.

Results

As of October 2020, 14 cases diagnosed with IBC have been found in 9,746 P-Y of follow up for an incidence of 144 cases per 100,000 P-Y, substantially less than the age-specific SEER incidence rates (223/100,000), placebo arm of Women's Health Initiative Study (330/100,000), and never users of hormone therapy from the Million Women Study (312/100,000).

Conclusion

T and/or T/E pellet implants significantly reduced the incidence of BC in pre- and post-menopausal women. The addition of E did not increase the incidence over using T alone. This is the second multi-year long-term study demonstrating the benefits of T therapy in reducing the incidence of IBC.

Physical activity, obesity and sedentary behavior in cancer etiology: epidemiologic evidence and biologic mechanisms

An estimated 30–40% of cancers can be prevented through changes in modifiable lifestyle and environmental risk factors known to be associated with cancer incidence. Despite this knowledge, there remains limited awareness that these associations exist. The purpose of this review article was to summarize the epidemiologic evidence concerning the contribution of physical activity, sedentary behavior, and obesity to cancer etiology and to provide an overview of the biologic mechanisms that may be operative between these factors and cancer incidence. Strong and consistent evidence exists that higher levels of physical activity reduce the risk of six different cancer sites (bladder, breast, colon, endometrial, esophageal adenocarcinoma, gastric cardia), whereas moderate evidence inversely associates physical activity with lung, ovarian, pancreatic and renal cancer, and limited evidence inversely correlates physical activity with prostate cancer. Sedentary behavior, independent of physical activity, has been shown to increase the risk of colon, endometrial, and lung cancers. Obesity is an established risk factor for 13 different cancer sites (endometrial, postmenopausal breast, colorectal, esophageal, renal/kidneys, meningioma, pancreatic, gastric cardia, liver, multiple myeloma, ovarian, gallbladder, and thyroid). The main biologic mechanisms whereby physical activity, sedentary behavior, and obesity are related to cancer incidence include an effect on endogenous sex steroids and metabolic hormones, insulin sensitivity, and chronic inflammation. Several emerging pathways related to oxidative stress, DNA methylation, telomere length, immune function, and gut microbiome are presented. Key recommendations for future research in both the epidemiology and biology of the associations between physical activity, sedentary behavior, obesity, and cancer risk are also provided.

Incidence of invasive breast cancer in women treated with testosterone implants: a prospective 10-year cohort study

BACKGROUND

Testosterone implants have been used for over eighty years to treat symptoms of hormone deficiency in pre and postmenopausal women. Evidence supports that androgens are breast protective. However, there is a lack of data on the long-term effect of testosterone therapy on the incidence of invasive breast cancer (IBC). This study was specifically designed to investigate the incidence of IBC in pre and postmenopausal women (presenting with symptoms of androgen deficiency) treated with subcutaneous testosterone implants or testosterone implants combined with anastrozole.

METHODS

The 10-year prospective cohort study was approved in March 2008 at which time recruitment was initiated. Recruitment was closed March 2013. Pre and postmenopausal women receiving at least two pellet insertions were eligible for analysis (N = 1267). Breast cancer incidence rates were reported as an unadjusted, un-weighted value of newly diagnosed cases divided by the sum of 'person-time of observation' for the at-risk population. Incidence rates on testosterone therapy were compared to age-specific Surveillance Epidemiology and End Results (SEER) incidence rates and historical controls. Bootstrap sampling distributions were constructed to verify comparisons and tests of significance that existed between our results and SEER data.

RESULTS

As of March 2018, a total of 11 (versus 18 expected) cases of IBC were diagnosed in patients within 240-days following their last testosterone insertion equating to an incidence rate of 165/100000 p-y, which is significantly less than the age-matched SEER expected incidence rate of 271/100000 p-y (p < 0.001) and historical controls.

CONCLUSION

Long term therapy with subcutaneous testosterone, or testosterone combined with anastrozole, did not increase the incidence of IBC. Testosterone should be further investigated for hormone therapy and breast cancer prevention.

Establishing a Cohort of Transgender Men and Gender Nonconforming Individuals to Understand the Molecular Impact of Testosterone on Breast Physiology

Purpose: To characterize a cohort of transgender men and masculine-centered gender nonconforming individuals who underwent gender-affirming chest-contouring surgeries at our institution between 2013 and 2018.

Methods: Demographics, medical history, and breast histopathological assessment for 340 patients were retrieved from medical records.

Results: Most of our patients were white, non-Hispanic (75.0%), were taking testosterone (83.2%), and opted for chest-contouring surgery after 12–14 months of testosterone therapy. Ten patients were parous (2.9%). Seventy-nine (23.2%) and 27 (7.9%) patients had a family history of breast cancer or ovarian cancer, respectively. One transgender man was incidentally diagnosed with ductal carcinoma in situ at chest-contouring surgery.

Conclusion: Future studies on this cohort will provide valuable insights about the impact of testosterone on breast physiology.

Impaired redox regulation of estrogen metabolizing proteins is important determinant of human breast cancers

Estrogen evidently involves critically in the pathogenesis of gynaecological-cancers. Reports reveal that interference in estrogen-signalling can influence cell-cycle associated regulatory-processes in female reproductive-organs. The major determinants that influence E2-signallings are estrogen-receptor (ER), estrogen-sulfotransferase (SULT1E1), sulfatase (STS), and a formylglycine-generating-enzyme (FGE) which regulates STS activity. The purpose of this mini review was to critically analyze the correlation between oxidative-threats and redox-regulation in the process of estrogen signalling. It is extensively investigated and reported that oxidative-stress is linked to cancer. But no definite mechanism has been explored till date. The adverse effects of oxidative-threat/free-radicals (like genotoxic-effects, gene-regulation, and mitochondrial impairment) have been linked to several diseases like diabetes/cardiovascular-syndrome/stroke and cancer. However, a significant correlation between oxidative-stress and gynaecological-cancers are repeatedly reported without pointing a definite mechanism. For the first time in our study we have investigated the relationship between oxidative stress and the regulation of estrogen via estrogen metabolizing proteins. Reports reveal that ER, SULT1E1, STS and FGE are target-molecules of oxidative-stress and may function differently in oxidizing and reducing environment. In addition, estrogen itself can induce oxidative-stress. This fact necessitates identifying the critical connecting events between oxidative-stress and regulation of estrogen-associated-molecules (ER, SULT1E1, STS, and FGE) that favors tumorigenesis/carcinogenesis. The current review focus is on unique redox-regulation of estrogen and its regulatory-molecules via oxidative-stress. This mechanistic-layout may identify new therapeutic-targets and open further scopes to treat gynecological-cancers more effectively.

Subcutaneous testosterone-letrozole therapy before and concurrent with neoadjuvant breast chemotherapy: clinical response and therapeutic implications

OBJECTIVE

Hormone receptor-positive breast cancers respond favorably to subcutaneous testosterone combined with an aromatase inhibitor. However, the effect of testosterone combined with an aromatase inhibitor on tumor response to chemotherapy was unknown. This study investigated the effect of testosterone-letrozole implants on breast cancer tumor response before and during neoadjuvant chemotherapy.

METHODS

A 51-year-old woman on testosterone replacement therapy was diagnosed with hormone receptor-positive invasive breast cancer. Six weeks before starting neoadjuvant chemotherapy, the patient was treated with subcutaneous testosterone-letrozole implants and instructed to follow a low-glycemic diet. Clinical status was followed. Tumor response to "testosterone-letrozole" and subsequently, "testosterone-letrozole with chemotherapy" was monitored using serial ultrasounds and calculating tumor volume. Response to therapy was determined by change in tumor volume. Cost of therapy was evaluated.

RESULTS

There was a 43% reduction in tumor volume 41 days after the insertion of testosterone-letrozole implants, before starting chemotherapy. After the initiation of concurrent chemotherapy, the tumor responded at an increased rate, resulting in a complete pathologic response. Chemotherapy was tolerated. Blood counts and weight remained stable. There were no neurologic or cardiac complications from the chemotherapy. Cost of therapy is reported.

CONCLUSIONS

Subcutaneous testosterone-letrozole was an effective treatment for this patient's breast cancer and did not interfere with chemotherapy. This novel combination implant has the potential to prevent side effects from chemotherapy, improve quality of life, and warrants further investigation.

MECHANISMS IN ENDOCRINOLOGY: Medical consequences of doping with anabolic androgenic steroids: effects on reproductive functions

Anabolic androgenic steroids (AASs) are appearance and performance-enhancing drugs (APEDs) used in competitive athletics, in recreational sports, and by body-builders. The global lifetime prevalence of AASs abuse is 6.4% for males and 1.6% for women. Many AASs, often obtained from the internet and dubious sources, have not undergone proper testing and are consumed at extremely high doses and in irrational combinations, also along with other drugs. Controlled clinical trials investigating undesired side effects are lacking because ethical restrictions prevent exposing volunteers to potentially toxic regimens, obscuring a causal relationship between AASs abuse and possible sequelae. Because of the negative feedback in the regulation of the hypothalamic-pituitary-gonadal axis, in men AASs cause reversible suppression of spermatogenesis, testicular atrophy, infertility, and erectile dysfunction (anabolic steroid-induced hypogonadism). Should spermatogenesis not recover after AASs abuse, a pre-existing fertility disorder may have resurfaced. AASs frequently cause gynecomastia and acne. In women, AASs may disrupt ovarian function. Chronic strenuous physical activity leads to menstrual irregularities and, in severe cases, to the female athlete triad (low energy intake, menstrual disorders and low bone mass), making it difficult to disentangle the effects of sports and AASs. Acne, hirsutism and (irreversible) deepening of the voice are further consequences of AASs misuse. There is no evidence that AASs cause breast carcinoma. Detecting AASs misuse through the control network of the World Anti-Doping Agency (WADA) not only aims to guarantee fair conditions for athletes, but also to protect them from medical sequelae of AASs abuse.

Rapid response of breast cancer to neoadjuvant intramammary testosterone-anastrozole therapy: neoadjuvant hormone therapy in breast cancer

Objective

Experimental and clinical data support the inhibitory effect of testosterone on breast tissue and breast cancer. However, testosterone is aromatized to estradiol, which exerts the opposite effect. The aim of this study was to determine the effect of testosterone, combined with the aromatase inhibitor anastrozole, on a hormone receptor positive, infiltrating ductal carcinoma in the neoadjuvant setting.

Methods

To determine clinical response, we obtained serial ultrasonic measurements and mammograms before and after therapy. Three combination implants—each containing 60 mg of testosterone and 4 mg of anastrozole—were placed anterior, superior, and inferior to a 2.4-cm tumor in the left breast. Three additional testosterone-anastrozole implants were again placed peritumorally 48 days later.

Results

By day 46, there was a sevenfold reduction in tumor volume, as measured on ultrasound. By week 13, we documented a 12-fold reduction in tumor volume, demonstrating a rapid logarithmic response to intramammary testosterone-anastrozole implant therapy, equating to a daily response rate of 2.78% and a tumor half-life of 23 days. Therapeutic systemic levels of testosterone were achieved without elevation of estradiol, further demonstrating the efficacy of anastrozole combined with testosterone.

Conclusions

This novel therapy, delivered in the neoadjuvant setting, has the potential to identify early responders and to evaluate the effectiveness of therapy in vivo. This may prove to be a new approach to both local and systemic therapies for breast cancer in subgroups of patients. In addition, it can be used to reduce tumor volume, allowing for less surgical intervention and better cosmetic oncoplastic results.

Dietary lignan intake and androgen receptor expression in breast tumors

PURPOSE

Lignans, a class of phytoestrogen commonly found in the Western diet, have been linked to decreased breast cancer risks in epidemiologic studies. Similar to estrogen receptors, the androgen receptor (AR), a prognostic factor in breast tumors, may be affected by lignans. However, few studies have investigated this link in the context of breast cancer etiology. We evaluated the relationship between dietary lignan intake and AR expression in incident breast tumors.

METHODS

Tumor tissue, epidemiological, and clinical data were collected from 216 women with incident, primary, histologically confirmed breast cancer enrolled in the Roswell Park Cancer Institute (RPCI) Data Bank and BioRepository (DBBR). On average, three tumor cores from each participant were assembled into a tissue micro array. After immunohistochemical staining, a trained RPCI pathologist determined AR status of each core. Lignan intake was calculated from a food frequency questionnaire collected upon enrollment into the DBBR.

RESULTS

We observed a weak positive association between dietary lignans and AR expression [β (SE) 27.6 (17.0), p 0.10], and there was no significant difference in lignan intake across categories of AR expression (p = 0.09, R (2) = 0.35).

CONCLUSION

Our results do not support a clear relationship between dietary lignan intake and AR expression. This investigation is the first, to our knowledge, to examine dietary lignan intake and AR expression in breast tumors. Further research is needed within a larger, more representative sample to determine whether lignan intake is truly associated with AR expression.

Benefits and risks of testosterone treatment for hypoactive sexual desire disorder in women: a critical review of studies published in the decades preceding and succeeding the advent of phosphodiesterase type 5 inhibitors

With advancing age, there is an increase in the complaints of a lack of a libido in women and erectile dysfunction in men. The efficacy of phosphodiesterase type 5 inhibitors, together with their minimal side effects and ease of administration, revolutionized the treatment of erectile dysfunction. For women, testosterone administration is the principal treatment for hypoactive sexual desire disorder. We sought to evaluate the use of androgens in the treatment of a lack of libido in women, comparing two periods, i.e., before and after the advent of the phosphodiesterase type 5 inhibitors. We also analyzed the risks and benefits of androgen administration. We searched the Latin-American and Caribbean Health Sciences Literature, Cochrane Library, Excerpta Medica, Scientific Electronic Library Online, and Medline (PubMed) databases using the search terms disfunção sexual feminina/female sexual dysfunction, desejo sexual hipoativo/female hypoactive sexual desire disorder, testosterona/testosterone, terapia androgênica em mulheres/androgen therapy in women, and sexualidade/sexuality as well as combinations thereof. We selected articles written in English, Portuguese, or Spanish. After the advent of phosphodiesterase type 5 inhibitors, there was a significant increase in the number of studies aimed at evaluating the use of testosterone in women with hypoactive sexual desire disorder. However, the risks and benefits of testosterone administration have yet to be clarified.

Effect of androgens on different breast cancer cells co-cultured with or without breast adipose fibroblasts

About 70% of breast tumors express androgen receptors. In addition, there is clinical evidence suggesting that androgens can inhibit mammary epithelial proliferation. Vice versa, there is also significant evidence indicating that androgens can increase the risk of breast cancer via multiple mechanisms, e.g. direct conversion to estrogens that can bind to the estrogen receptor and thereby stimulate cell proliferation. We examined the effect of testosterone (T) and dihydroxytestosterone (DHT) on cell proliferation, pS2 and Ki-67 expression in three different breast cancer cell lines alone or in co-culture with primary human breast adipose fibroblasts (BAFs) obtained from breast cancer patients. In the co-cultures, T induced cell proliferation, pS2 and Ki-67 expression in the estrogen receptor positive (ER(+)) MCF-7 and T47D cells. This was not observed in the (ER(-)) MDA-MB-231 cells. The differences might be explained by the high expression of aromatase, which converts androgens to estrogens in BAFs followed by ER-mediated cell proliferation. In line with this absence of increased cell proliferation, pS2 and Ki-67 expression was observed in the presence of DHT, which is not a substrate for aromatase. In contrast, DHT caused a significant suppression of cell proliferation (68% and 38%), pS2 and Ki-67 expression in the (ER(+)) MCF-7 and T47D cells. More importantly, DHT decreased cell proliferation in (ER(-)) MDA-MB-231 cells by 38%. The results suggest that androgens that cannot be aromatized, like DHT, may provide a perspective for treatment of breast cancer patients, especially those with triple negative breast cancer.

Androgen receptor may be responsible for gender disparity in gastric cancer

Men are at a higher risk of developing gastric cancer than women. However, the exact mechanisms responsible for the gender differences remain unclear. Recently, a number of epidemiological and genotyping studies have attributed the gender disparity in male-predominant cancers to the disruption of androgen receptor (AR) homeostasis. Moreover, previous data indicated that AR expression is an independent unfavorable prognostic factor in gastric cancer, suggesting that AR may play an important role in gastric carcinogenesis. In addition, mounting evidence suggests that AR is involved in many signaling pathways associated with gastric carcinogenesis. On the basis of the aforementioned evidence, we postulate that AR exhibits oncogenic properties in gastric cancer via several possible mechanisms, which may partly explain the higher prevalence of gastric cancer among males.

Androgens inhibit the stimulatory action of 17β-estradiol on normal human breast tissue in explant cultures

BACKGROUND

The data concerning the effects and safety of androgen in human breast tissue are conflicting.

OBJECTIVE

Our aim was to analyze the effects of androgens on normal human breast tissue (HBT).

APPROACH

We cultured explants of HBT (obtained from reduction mammoplasty operations of postmenopausal women) with or without testosterone (T) and 5α-dihydrotestosterone (DHT) or in combination with 17β-estradiol (E(2)) for 7 and 14 d to study the effects of androgens on proliferation, apoptosis, target gene expression, and steroid receptors. The androgen receptor (AR) and estrogen receptor (ER) dependences of the effects were studied with the antihormones bicalutamide and fulvestrant, respectively.

RESULTS

The hormone responsiveness of cultured breast tissue was assessed by assaying apolipoprotein-D and prostate-specific antigen expression increased by androgens and amphiregulin and trefoil factor-1 expression induced by E(2) treatment. T and DHT reduced proliferation and increased apoptosis in breast epithelium, the effects of which were reversed by bicalutamide. In combination with E(2), they suppressed E(2)-stimulated proliferation and cell survival. DHT also inhibited basal (P < 0.05) and E(2)-induced expression of cyclin-D1 mRNA (P < 0.05). Immunohistochemistry showed that T (P < 0.05) and DHT (P < 0.05) increased the relative number of AR-positive cells, whereas ERα-positive (P < 0.001) cell numbers were strongly decreased. The percentage of ERβ-positive cells remained unchanged. E(2) treatment increased ERα-positive (P < 0.01) cells, whereas AR- (P < 0.05) and ERβ-expressing (P < 0.001) cells diminished. These effects were repressed in combination cultures of E(2) with T and DHT.

CONCLUSION

T and DHT inhibited proliferation and increased apoptosis in the epithelium of cultured normal HBT and opposed E(2)-stimulated proliferation and cell survival in an AR-dependent manner. These effects were associated with changes in the proportions of ERα- and AR-positive epithelial cells.