Predicting factors for progression to castration resistance prostate cancer after biochemical recurrence in patients with clinically localized prostate cancer who underwent radical prostatectomy.

BACKGROUND: To determine prognostic factors associated with progression to castration-resistant prostate cancer following biochemical recurrence which is lethal prostate cancer and establish a risk stratification model of progression to castration-resistant prostate cancer. METHODS: We retrospectively reviewed the data of 550 patients who experienced biochemical recurrence after radical prostatectomy. The endpoint of the present study was progression to castration-resistant prostate cancer. The actuarial probabilities of progression to castration-resistant prostate cancer-free survival were determined using Kaplan-Meier analysis. Univariate and multivariate Cox proportional hazards regression analyses were used to identify independent predictors of biochemical recurrence. RESULTS: Fifty-two patients experienced progression to castration-resistant prostate cancer during the follow-up period. The progression to castration-resistant prostate cancer-free survival rate after biochemical recurrence at 10 years was 76.8%. In multivariate analysis, pathological Gleason score ≥ 9, lymphovascular invasion, and prostate-specific antigen velocity ≥ 0.4 ng/mL/year were independent predictive factors for progression to castration-resistant prostate cancer. The patients were stratified into three groups using a risk stratification model incorporating these variables. The 10-year progression to castration-resistant prostate cancer-free survival rates were 96.7% in the low-risk group, 84.7% in the intermediate-risk group, and 24.5% in the high-risk group. CONCLUSIONS: The present results suggest that the pathological Gleason score, lymphovascular invasion, and prostate-specific antigen velocity were independent predictive factors for progression to castration-resistant prostate cancer. The risk stratification model established in the present study could be useful for patient counseling and in identifying patients with a poor prognosis.

The significance of micro-lymphatic invasion and pathological Gleason score in prostate cancer patients with pathologically organ-confined disease and negative surgical margins after robot-assisted radical prostatectomy.

BACKGROUND: The development process of recurrence in prostate cancer patients with pathologically organ-confined (pT2) disease and negative surgical margins is unclear. The aim of the present study was to determine factors associated with the development of biochemical recurrence following robot-assisted radical prostatectomy among those prostate cancer patients. METHODS: We retrospectively reviewed the data of patients who underwent robot-assisted radical prostatectomy without neoadjuvant endocrine therapy. We evaluated prognostic factors in 1096 prostate cancer patients with pT2 disease and negative surgical margins. Univariate and multivariate Cox proportional hazards regression analyses were used to identify independent predictors for biochemical recurrence. RESULTS: Of the 1096 patients, 55 experienced biochemical recurrence during the follow-up period. The 5-year biochemical recurrence-free survival rate for patients with pT2 and negative surgical margins was 91.8%. On univariate analysis, clinical stage, biopsy Gleason score, percent of positive core, pathological Gleason score, and the presence of micro-lymphatic invasion were significantly associated with biochemical recurrence. On a multivariate analysis, the presence of micro-lymphatic invasion and a pathological Gleason score ≥ 4 + 3 were significant prognostic factors for biochemical recurrence. Based on these factors, we developed a risk stratification model. The biochemical recurrence-free survival rate differed significantly among the risk groups. CONCLUSIONS: The prognosis of prostate cancer patients with pT2 disease and negative surgical margins is favorable. However, patients with the presence of micro-lymphatic invasion and a pathological Gleason score ≥ 4 + 3 tend to experience biochemical recurrence more often after surgery. Therefore, careful follow-up might be necessary for those patients.

Comparing protein and mRNA expressions of the human epidermal growth factor receptor family in estrogen receptor-positive breast cancer.

The human epidermal growth factor receptor (HER) family plays a vital role in the development of resistance to treatments in estrogen receptor (ER)-positive breast cancer. This study investigated the correlation between protein and mRNA expressions of the HER family in ER-positive breast cancer. We dissected regions of invasive cancer from the frozen tissues of 34 patients with ER-positive breast cancer using laser-capture microdissection, followed by evaluation of the mRNA levels of the ER and HER family (EGFR, HER2, HER3, and HER4) using the quantitative reverse transcription polymerase chain reaction (qRT-PCR) assay. In addition, we assessed the protein expressions of the ER and HER family using an immunohistochemical (IHC) assay. A significant correlation was observed between the ER protein and mRNA expressions. For HER2, HER3, and HER4, protein expressions significantly correlated with mRNA levels. We established significant correlations of the mRNA level between EGFR versus HER2, as well as EGFR versus HER3. Furthermore, a significant correlation of the mRNA level between HER2 and HER3 was illustrated. In conclusion, IHC evaluation may be reliable and representable for mRNA. Hence, this study established a marked correlation between the mRNA expressions of HER family members in patients with ER-positive breast cancer.

Recent trends in microRNA research into breast cancer with particular focus on the associations between microRNAs and intrinsic subtypes.

MicroRNAs (miRNAs) are short non-coding RNAs that regulate the function of target genes at the post-transcriptional phase. miRNAs are considered to have roles in the development, progression and metastasis of cancer. Recent studies have indicated that particular miRNA signatures are correlated with tumor aggressiveness, response to drug therapy and patient outcome in breast cancer. On the other hand, in routine clinical practice, the treatment regimens for breast cancer are determined based on the intrinsic subtype of the primary tumor. Previous studies have shown that miRNA expression profiles of each intrinsic subtypes of breast cancer differ. In hormone receptor-positive/human epidermal growth factor receptor 2 (HER2)-negative breast cancer, miRNA expressions are found to be correlated with endocrine therapy resistance, progesterone receptor expression and heat shock protein activity. Some miRNAs are associated with resistance to HER2-targeted therapy and HER3 expression in HER2-positive breast cancer. In triple-negative breast cancer, miRNA expressions are found to be associated with BRCA mutations, immune system, epithelial-mesenchymal transition, cancer stem cell properties and androgen receptor expression. As it has been clarified that the expression levels and functions of miRNA differ among the various subtypes of breast cancer, and it is necessary to take account of the characteristics of each breast cancer subtype during research into the roles of miRNA in breast cancer. In addition, the discovery of the roles played by miRNAs in breast cancer might provide new opportunities for the development of novel strategies for diagnosing and treating breast cancer.

Possible role of the aromatase-independent steroid metabolism pathways in hormone responsive primary breast cancers.

Aromatase inhibitors (AIs) exert antiproliferative effects by reducing local estrogen production from androgens in postmenopausal women with hormone-responsive breast cancer. Previous reports have shown that androgen metabolites generated by the aromatase-independent enzymes, 5α-androstane-3ß, 17ß-diol (3ß-diol), androst-5-ene-3ß, and 17ß-diol (A-diol), also activate estrogen receptor (ER) α. Estradiol (E2) can also reportedly be generated from estrone sulfate (E1S) pooled in the plasma. Estrogenic steroid-producing aromatase-independent pathways have thus been proposed as a mechanism of AI resistance. However, it is unclear whether these pathways are functional in clinical breast cancer. To investigate this issue, we assessed the transcriptional activities of ER in 45 ER-positive human breast cancers using the adenovirus estrogen-response element-green fluorescent protein assay and mRNA expression levels of the ER target gene, progesterone receptor, as indicators of ex vivo and in vivo ER activity, respectively. We also determined mRNA expression levels of 5α-reductase type 1 (SRD5A1) and 3ß-hydroxysteroid dehydrogenase type 1 (3ß-HSD type 1; HSD3B1), which produce 3ß-diol from androgens, and of steroid sulfatase (STS) and 17ß-hydroxysteroid dehydrogenase type 1 (17ß-HSD type 1; HSD17B1), which produce E2 or A-diol from E1S or dehydroepiandrosterone sulfate. SRD5A1 and HSD3B1 expression levels were positively correlated with ex vivo and in vivo ER activities. STS and HSD17B1 expression levels were positively correlated with in vivo ER activity alone. Elevated expression levels of these steroid-metabolizing enzymes in association with high in vivo ER activity were particularly notable in postmenopausal patients. Analysis of the expression levels of steroid-metabolizing enzymes revealed positive correlations between SRD5A1 and HSD3B1, and STS and HSD17B1. These findings suggest that the SRD5A1-HSD3B1 as well as the STS-HSD17B pathways, could contributes to ER activation, especially postmenopause. These pathways might function as an alternative estrogenic steroid-producing, aromatase-independent pathways.

Androgen metabolite-dependent growth of hormone receptor-positive breast cancer as a possible aromatase inhibitor-resistance mechanism.

Aromatase inhibitors (AIs) have been reported to exert their antiproliferative effects in postmenopausal women with hormone receptor-positive breast cancer not only by reducing estrogen production but also by unmasking the inhibitory effects of androgens such as testosterone (TS) and dihydrotestosterone (DHT). However, the role of androgens in AI-resistance mechanisms is not sufficiently understood. 5α-Androstane-3ß,17ß-diol (3ß-diol) generated from DHT by 3ß-hydroxysteroid dehydrogenase type 1 (HSD3B1) shows androgenic and substantial estrogenic activities, representing a potential mechanism of AI resistance. Estrogen response element (ERE)-green fluorescent protein (GFP)-transfected MCF-7 breast cancer cells (E10 cells) were cultured for 3 months under steroid-depleted, TS-supplemented conditions. Among the surviving cells, two stable variants showing androgen metabolite-dependent ER activity were selected by monitoring GFP expression. We investigated the process of adaptation to androgen-abundant conditions and the role of androgens in AI-resistance mechanisms in these variant cell lines. The variant cell lines showed increased growth and induction of estrogen-responsive genes rather than androgen-responsive genes after stimulation with androgens or 3ß-diol. Further analysis suggested that increased expression of HSD3B1 and reduced expression of androgen receptor (AR) promoted adaptation to androgen-abundant conditions, as indicated by the increased conversion of DHT into 3ß-diol by HSD3B1 and AR signal reduction. Furthermore, in parental E10 cells, ectopic expression of HSD3B1 or inhibition of AR resulted in adaptation to androgen-abundant conditions. Coculture with stromal cells to mimic local estrogen production from androgens reduced cell sensitivity to AIs compared with parental E10 cells. These results suggest that increased expression of HSD3B1 and reduced expression of AR might reduce the sensitivity to AIs as demonstrated by enhanced androgen metabolite-induced ER activation and growth mechanisms. Androgen metabolite-dependent growth of breast cancer cells may therefore play a role in AI-resistance.

Differences in Analgesia Methods for Open Gastrointestinal Surgery Are Not Associated With Initial Postoperative Ambulation.

Background: A characteristic of modern medical care is the reduction in the length of hospital stay, and several facilities across Japan are working towards this goal. The presence of postoperative pain is correlated with the number of days to hospital discharge. Therefore, this study investigated the relationship between the analgesic methods used in clinical practice and the initial ambulation of postoperative laparotomy patients with severe postoperative worked incisional pain to enable better analgesic management in the future. Methods: This retrospective study collected information from the medical records of 117 patients who underwent laparotomy between December 1, 2019, and October 13, 2020, at the Department of Gastroenterology of the International University of Health and Welfare Mita Hospital. Based on the failure or success of the ambulation process, the patients were divided into the delayed and successful groups, respectively. Results: In the delayed group, patient-controlled epidural analgesia (PCEA) was used in 32 patients, intravenous patient-controlled analgesia (IV-PCA) was used in two patients, continuous worked incisional infiltration anesthesia was used in one patient, and transvenous acetaminophen was used in one patient for postoperative analgesia. In the successful group, PCEA was used in 66 patients, IV-PCA was used in 11 patients, continuous worked incisional infiltration anesthesia was used in three patients, and acetaminophen administered intravenously at patient's request was used in one patient (P = 0.094). Conclusions: No significant differences were observed between different postoperative analgesia methods, suggesting that there may be no association between postoperative ambulation and the postoperative analgesia method.

Predictors of Catheter-Related Bladder Discomfort After Surgery: A Literature Review.

Background: Indwelling bladder catheters are routinely used in clinical practice. Patients may experience postoperative indwelling catheter-related bladder discomfort (CRBD). This study aimed to perform a literature review to identify predictors of postoperative CRBD. Methods: We searched PubMed for relevant articles published between 2000 and 2020 using the search items "CRBD", "catheter-related bladder discomfort", and "prediction". Additionally, we searched for articles that matched the research objectives from the references of the extracted articles. We included only prospective observational studies involving human participants and excluded interventional studies, observational studies that did not report sample sizes, or observational studies that did not research on predictors of CRBD. We narrowed our search to the keyword "prediction" and found five references. We selected five studies that met the objectives of the study as the target literature. Results: Using the keywords "CRBD" and "catheter-related bladder discomfort", we identified 69 published articles. The results were narrowed down by the keyword "prediction", and five studies that recruited 1,147 patients remained. The predictors of CRBD can be divided into four factors: 1) patient factors; 2) surgical factors; 3) anesthesia factors; and 4) device and insertion technique factors. Conclusion: Our study suggests that patients with predictors of CRBD should be closely monitored to reduce postoperative patient suffering, and their quality of life should be improved after anesthesia.

ER-activating ability of breast cancer stromal fibroblasts is regulated independently of alteration of TP53 and PTEN tumor suppressor genes.

Carcinoma-associated fibroblasts (CAFs) are associated with tumor progression and metastasis, and are able to activate estrogen receptor (ER) in breast cancer. We established a stable transformant of a human breast cancer cell line to detect CAF-specific ER-activating ability, and found that this CAF ability varied among tumors. Some studies have reported a high frequency of alterations among tumor suppressor genes in stromal cells, but do not generally agree as to the frequency. Moreover, the activation mechanism of CAF-induced estrogen signals, including the effects of these gene aberrations, is not fully understood. We investigated the relevance of tumor suppressor gene aberrations and ER-activating ability in CAFs derived from 20 breast cancer patients. Although CAF-specific ER-activating abilities varied among individual cases, all CAFs maintained wild-type alleles for TP53 and PTEN. Also, copy number aberrations in these genes were not observed in any CAFs. Our results suggest that the ER-activating ability of the CAFs is regulated independently of aberrations in these genes; and that other mechanisms of tumor-stromal interaction may affect activation of estrogen signals in breast cancer.

Estrogen receptor-α directly regulates sensitivity to paclitaxel in neoadjuvant chemotherapy for breast cancer.

Neoadjuvant chemotherapy (NAC) has become the standard treatment for advanced breast cancer. Several prognostic markers, including estrogen receptor-α (ERα), are used to predict the response to NAC. However, the molecular significance of ERα expression in the efficacy of chemotherapy is not yet fully understood. To examine this issue, we first evaluated ERα transcriptional activity in breast cancer cells derived from pre-NAC specimens using estrogen response element-green fluorescent protein (ERE-GFP) as a reporter gene, and found that, in the cases for which ERα activities determined by GFP expression were not detected or low, pCR (pathological complete response) could be achieved even though ERα protein was expressed. Next, we examined the effects of alterations in ERα expression levels on sensitivity to paclitaxel, a key drug in NAC, by stable expression of ERα in ER-negative SKBR3 cells and by siRNA-mediated down-regulation of ERα in ER-positive MCF-7 cells, and showed that ERα expression and sensitivity to paclitaxel showed an inverse correlation. We also established paclitaxel-resistant MCF-7 cell clones and found that they have higher estrogen-induced ER activity than parent cells. Paclitaxel is a microtubule-stabilizing agent, while HDAC6 (histone deacetylase 6), which we previously identified as an estrogen-regulated gene, enhances cell motility by destabilizing microtubules via deacetylation of α-tubulin. Finally, we demonstrate herein that ERα knockdown in MCF-7 cells prevents deacetylation of α-tubulin, thereby increasing sensitivity to paclitaxel. Taken together, these results suggest that ERα expression directly regulates sensitivity to paclitaxel in NAC for breast cancer via the effect on microtubule stability.

A Literature Review of Factors Related to Postoperative Sore Throat.

Postoperative sore throat can occur as a complication in patients who have undergone surgery under general anesthesia. The incidence of postoperative sore throat ranges from 12.1% to 70%, and its effects include damage to the epithelium and mucosal cells caused by airway securement, damage to the vocal cords, congestion, blood clots, and factors such as an inappropriately large tube, cuff shape, cuff pressure, and airway securement. Notably, there are individual differences in pain thresholds, and the sensation of pain is affected by mental states, such as anxiety, and varies from person to person. Therefore, we conducted a literature review using PubMed to clarify patient factors related to the development of postoperative sore throat. The extracted keywords were "postoperative sore throat," "anesthesia," and "patient factors." We found 16 articles that met our search criteria. We expanded the search period and retrieved 19 cases from 1990 to 2020. We also included references that were judged to be closely related to the list of citations of the retrieved references. The study designs included were randomized controlled trials, clinical trials, meta-analyses, reviews, and systematic reviews. The results showed that female sex, smoking, and age were the most common patient factors. However, we could not find any literature that studied the relationship between postoperative sore throat and mental states such as anxiety.

One DNA Methylation Regulates CHIP Gene Expression of Human Breast Cancer and Predicts Recurrence.

BACKGROUND/AIM: Carboxyl terminus of Hsc70-interacting protein (CHIP) is a ubiquitin ligase that induces ubiquitination and degradation of its target proteins including oncoproteins. We reported that its down-regulation is associated with tumor progression and metastasis of breast cancer. However, the mechanism through which CHIP gene affects cancer cells is unclear. MATERIALS AND METHODS: We extracted RNA from 45 primary breast cancer samples and compared CHIP mRNA expression profiles, promoter DNA methylation status, and clinicopathological information. RESULTS: CHIP mRNA expression was significantly correlated with the tumor progression status. In several samples, a pinpoint CpG methylation in the CHIP gene promoter region was significantly correlated with CHIP mRNA expression. When this specific CpG was methylated in estrogen receptor (ER)-positive cases, a significant difference in 5-year recurrence was not found compared with ER-negative cases. CONCLUSION: CpG methylation contributes to the long-term prognosis of ER-positive breast cancer.

Prostate-specific antigen nomogram to predict advanced prostate cancer using area under the receiver operating characteristic curve boosting.

BACKGROUND: For prostate cancer, accurate prediction of the pathological stage before surgery is very important. Therefore, the aim of the present study was establishing the prostate-specific antigen (PSA) threshold nomogram to predict pathologically advanced prostate cancer using the novel method of area under the receiver operating characteristic curve boosting (AUCBoost). METHODS: The medical records of patients with clinically localized prostate cancer who underwent robot-assisted radical prostatectomy were retrospectively reviewed. Multivariate logistic regression analysis was performed to identify clinical covariates significantly associated with pathological tumor stage ≥3a. The best combination of the variables was determined by validated values of the area under the curve (AUC). The optimal individualized PSA threshold values were developed using AUCBoost. RESULTS: In the multivariate logistic regression analysis, PSA, prostate volume, clinical tumor stage, Gleason Grade Group, the number of positive cores, and the percentage of positive cores were independent predictive factors for pathological tumor stage ≥3a. A combination model comprising PSA, prostate volume, clinical tumor stage, percent positive core, and Gleason Grade Group produced the highest AUC for predicting pathological tumor stage ≥3a (AUC = 0.777). The PSA threshold values for detecting pathological tumor stage ≥3a were calculated and a table of individualized PSA threshold nomogram was developed using AUCBoost. CONCLUSIONS: We developed a nomogram of the PSA threshold values for predicting adverse pathological tumor stages of prostate cancer using a novel statistical method. Further validation is necessary; however, the individualized PSA threshold nomogram may be useful in determining treatment strategies before surgery.

Heregulin controls ERα and HER2 signaling in mammospheres of ERα-positive breast cancer cells and interferes with the efficacy of molecular targeted therapy.

Estrogen receptor (ER)α and the human epidermal growth factor receptor (HER) family are inversely expressed in ERα-positive cancer in association with resistance to hormonal therapy, but the mechanism underlying their relationship remains unknown. We analyzed the effect of HER family ligands on the expression of ER and the HER family in ERα-positive MCF-7 and T47D breast cancer cell lines in 3D spheroid culture. Here, we demonstrated for the first time that heregulin-1ß (HRG), a HER3 and HER4 ligand, most effectively regulated ER/HER family expression by decreasing ERα mRNA expression and increasing HER family mRNA expression. HRG treatment attenuated fulvestrant-mediated growth inhibition, and promoted the migration of MCF-7 cells. Moreover, HRG increased the CD44+/CD24- cell fraction and side population cells, both of which are recognized as prospective breast cancer stem cell markers. HRG activated both phosphatidylinositol 3-kinase/AKT/mammalian target of rapamycin (PI3K/AKT/mTOR) and mitogen-activated protein kinase (MAPK) pathways. Inhibitors of these pathways reduced the growth of MCF-7 cells, but the addition of HRG has different effects on these pathways. HRG blocked the inhibitory effect of mTOR inhibitors, such as rapamycin and everolimus, on cell growth but not that of a PI3K inhibitor. Furthermore, HRG slightly decreased the inhibitory effect of an AKT inhibitor on cell growth. In contrast, HRG enhanced the MEK inhibitor-induced inhibition of cell growth. These findings suggest that HRG-stimulated signaling pathways allow ERα-positive breast cancer cells to escape from growth inhibition caused by everolimus, via MAPK signaling and/or other signaling pathways. Everolimus improves progression-free survival in combination with exemestane as second-line therapy for metastatic hormone receptor-positive breast cancer. Our study suggests that HRG is a novel target for ERα-positive breast cancer therapy.

Characterization of a membrane-associated estrogen receptor in breast cancer cells and its contribution to hormone therapy resistance using a novel selective ligand.

The estrogen receptor (ER) plays a role in the progression of hormone-dependent breast cancer and is a hormone therapy target. Estrogen acts as a transcription factor (genomic action) and also produces a quick non-genomic reaction through intracellular signaling pathways. The membrane associated ER (mER) may regulate both these signals and hormone therapy resistance. However, the details remain unclear because a reliable method to distinguish the signals induced by the estradiol (E2)-mER and E2-nuclear ER complex has not been established. In the present study, we prepared the novel ligand Qdot-6-E2, selective for mER, by coupling E2 with insoluble quantum dot nano-beads. We investigated the characteristics of mER signaling pathways and its contribution to hormone therapy resistance using different cell lines including estrogen depletion resistant (EDR) cells with different mechanisms. Qdot-6-E2 stimulated proliferation of nuclear ER-positive cells, but nuclear ER-negative cells showed no response. In addition, Qdot-6-E2 indirectly activated nuclear ER and increased mRNA expression of target genes. We confirmed that E2 was not dissociated from Qdot-6-E2 using a mammalian one-hybrid assay. We visually demonstrated that Qdot-6-E2 acts from the outside of cells. The gene expression profile induced by Qdot-6-E2-mER was different from that induced by E2-nuclear ER. The effect of anti-ER antibody, the GFP-ER fusion protein localization, and the effect of palmitoyl acyltransferase inhibitor also indicated the existence of mER. Regarding intracellular phosphorylation signaling pathways, the MAPK (Erk 1/2) and the PI3K/Akt pathways were both activated by Qdot-6-E2. In EDR cells, only nuclear ER-positive cells showed increased cell proliferation with increased localization of ERα to the membrane fraction. These findings suggested that Qdot-6-E2 reacts with ERα surrounding the cell membrane and that mER signals help the cells to survive under estrogen-depleted conditions by re-localizing the ER to use trace amounts of E2 more effectively. We expect that Qdot-6-E2 is a useful tool for studying the mER.

Estrogen signaling pathway and its imaging in human breast cancer.

Recent remarkable progress in hormonal therapy has provided great benefit to breast cancer patients, but it also evokes novel issues: how accurately can the efficacy of each hormonal therapy be predicted and how can hormonal therapy-resistant patients be treated? These clinically important issues must be closely related to the biological events in each cancer, such as the alteration of intracellular multiple estrogen signaling pathways and the estrogen-related cancer microenvironment, which has recently revealed by molecular biological studies on estrogen and its receptors. However, the estrogen signaling status in individual breast cancers has not been clarified yet. Here we present the context of these issues and introduce our study of new tools which enable the visualization of estrogen signals in individual cancers. The assessment of estrogen receptor (ER)-alpha activity in individual cancers or ER-activating ability of the cancer microenvironment in each breast cancer patient revealed several new findings and interesting observations. We hope that these approaches provide new clues about the estrogen-dependent mechanisms of breast cancer development, and will be useful to advance the diagnosis and treatment of breast cancer patients.

Estrogen-related cancer microenvironment of breast carcinoma.

Stromal cells establish the microenvironment based on interaction with tumor cells, which is essential for cancer growth, invasion and metastasis. Fibroblasts are the primary component of stroma, and carcinoma-associated fibroblasts (CAFs) demonstrate tumor-promoting activities compared with normal counterparts. In breast cancers, stromal fibroblasts adjacent to the tumor express aromatase, a key enzyme in the synthesis of estrogen, resulting in in situ estrogen production, and aromatase is a primary target of endocrine therapy. Thus, stromal fibroblasts demonstrate multiple functions in the genesis and progression of breast cancers. In this paper, we discuss the importance of tumor-stromal crosstalk in breast cancers, and describe our system to predict the efficacy of endocrine therapy and to analyze estrogen signals in individual breast cancers.

Aromatase localization in human breast cancer tissues: possible interactions between intratumoral stromal and parenchymal cells.

Aromatase is a key enzyme in intratumoral estrogen production required for the production of estrogens through the conversion of serum androgens in postmenopausal breast cancer patients. There have been, however, controversies regarding the intratumoral localization of aromatase in human breast carcinoma tissues. Therefore, we have first examined the intratumoral localization of aromatase mRNA/protein in 19 breast carcinomas using laser capture microdissection/quantitative reverse transcription-PCR (RT-PCR) and immunohistochemistry. Aromatase mRNA and protein were detected in both intratumoral stromal and parenchymal cells in breast carcinoma tissues. Subsequent microarray expression profiling and clustering analyses, in addition to quantitative RT-PCR studies, showed a significant positive correlation between aromatase and estrogen-related receptor alpha mRNA expression in isolated carcinoma cells. We further examined an interaction between stromal cells isolated from human breast carcinoma tissues and breast carcinoma cell lines using a coculture system to study the biological characteristic of aromatase expression in carcinoma cells. Aromatase mRNA and enzyme activity and 17beta-hydroxysteroid dehydrogenase type 1 mRNA in breast carcinoma cell lines, including MCF-7 and SK-BR-3 cells, were up-regulated in the presence of patient-derived 32N or 74T intratumoral stromal cells. The results from steroid conversion assays were also consistent with the findings above. The results of our study also showed that aromatase inhibitors were more effective in inhibiting aromatization induced by coculture in MCF-7 than that in stromal 32N. The examination of the localization of aromatase and its regulation, including the interactions existing between different cell types in human breast carcinoma tissues, may provide important information as to achieving better clinical response to aromatase inhibitors in breast cancer patients.

Tumor microenvironmental growth factors induce long-term estrogen deprivation resistance in breast cancer.

BACKGROUND: Hormonal therapy is an effective treatment for luminal-like breast cancer. Aromatase inhibitor (AI) is widely used for estrogen receptor-positive, postmenopausal breast cancers. However, resistance is occurred and becomes a serious clinical concern. In general, progression of cancer strongly depends on tumor microenvironment, which may, therefore, also contribute to the development of AI resistance. METHODS: We evaluated tumor microenvironment-derived factors with respect to AI resistance using typical estrogen receptor-positive breast cancer cell lines. We established tumor microenvironment-dependent AI-resistant models and elucidated the underlying mechanisms. RESULTS: T-47D cells had a higher dependence on microenvironment-derived factors, such as estrogen or growth factors, for survival than MCF-7 cells. We, therefore, evaluated tumor microenvironment growth factors with respect to AI resistance using T-47D cells. We established three resistant cell lines (V1, V2, and V3) that survived estrogen deprivation and growth factor-supplemented conditions. These cell lines were deficient in estrogen receptor α expression and estrogen-dependent growth. Among six representative growth factors, epidermal growth factor was the most influential. In these models, HER2 protein was overexpressed without gene amplification and intracellular phosphorylation pathways were activated compared to parental cell lines. Molecular targeting inhibitors revealed that V1 and V2 primarily rely on the PI3 K pathway for survival, whereas V3 relies on the MAPK pathway. CONCLUSIONS: This study demonstrates the importance of tumor microenvironment-derived factors for the development of AI resistance. These resistant models did not utilize the same resistance mechanism, suggesting that flexible strategies are essential in conquering resistance.

Utility of Ki67 labeling index, cyclin D1 expression, and ER-activity level in postmenopausal ER-positive and HER2-negative breast cancer with neoadjuvant chemo-endocrine therapy.

In this study, we investigated the relationships of pathological response after neoadjuvant chemo-endocrine therapy with alterations in the Ki67 labeling index (LI), expression of cyclin D1 (CCND1) and progesterone receptor (PgR), and estrogen receptor (ER) activity in breast cancer. A total of 43 Japanese post-menopausal ER-positive and human epidermal growth factor receptor 2-negative invasive breast cancer patients with tumors >2 cm or positive lymph nodes were enrolled. Exemestane alone was administered for 2 months. Neoadjuvant chemo-endocrine therapy included four cycles of doxorubicin plus paclitaxel followed by weekly paclitaxel. The immunohistochemical expression of Ki67 LI, CCND1, and PgR, and ER activity were evaluated using core needle biopsy samples at the pretreatment and post-exemestane alone stages. ER activity was evaluated through transfection of an adenovirus vector carrying an estrogen-response element-green fluorescent protein gene. In current study, marked pathological responses (including 4.7% with pathological complete response) were obtained in 34.9% of patients. Ki67 LI and PgR expression were significantly decreased after treatment. High Ki67 LI at pretreatment was a significant predictive factor of marked pathological response. At the stage of post-exemestane alone, Ki67 LI was not significantly associated with pathological response; however, high CCND1 expression was significantly correlated with high Ki67 LI. Moreover, low-level ER activity at the post-exemestane alone stage was significantly associated with marked pathological response. In conclusions, pretreatment Ki67 LI was a predictor of response to neoadjuvant chemo-endocrine therapy. CCND1 expression and ER activity at the post-endocrine therapy alone stage may be useful in determining further treatments.