Stromal Caveolin-1 Expression Research Articles

Caveolin-1 protein expression as a prognostic biomarker of gastrointestinal tumours: A systematic review and meta-analysis.

Gastrointestinal (GI) cancers remain a major threat worldwide, accounting for over 30% of cancer deaths. The identification of novel prognostic biomarkers remains a challenge despite significant advances in the field. The CAV1 gene, encoding the caveolin-1 protein, remains enigmatic in cancer and carcinogenesis, as it has been proposed to act as both a tumour promoter and a tumour suppressor. To analyse the differential role of caveolin-1 expression in both tumour cells and stroma in relation to prognosis in GI tumours, we performed a systematic review and meta-analysis according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses (PRISMA) guidelines; PROSPERO registration number: CRD42022299148. Our analysis showed that high levels of caveolin-1 in tumour cells were associated with poor prognosis and inferior overall survival (OS) in oesophageal and pancreatic cancer and hepatocellular carcinoma (HCC), but not in gastric and colorectal cancer. Importantly, our study showed that higher stromal caveolin-1 expression was associated with significantly longer OS and disease-free survival in colorectal cancer. Analysis of stromal caveolin-1 expression in the remaining tumours showed a similar trend, although it did not reach statistical significance. The data suggest that caveolin-1 expression in the tumour cells of oesophageal, pancreatic cancer and HCC and in the stroma of colorectal cancer may be an important novel predictive biomarker for the clinical management of these diseases in a curative setting. However, the main conclusion of our analysis is that caveolin-1 expression should always be assessed separately in stroma and tumour cells.

Abstract P3-02-12: CAV1, MCT1, and MCT4 expression in ductal carcinoma in situ of the breast and its association with clinicopathologic features

Abstract Background: Multicompartment tumor metabolism and metabolic coupling are markers of aggressive tumor behavior, clinically manifested as disease recurrence and progression. Loss of caveolin-1(CAV1) in stromal cells and upregulation of monocarboxylate transporters (MCTs), especially MCT1 and MCT4, in both stromal and cancer cells have been identified as playing an important role in the metabolic coupling necessary for release and uptake of metabolites. However, this phenomenon has only scarcely been described in ductal carcinoma in situ (DCIS) of the breast. The purpose of this study was to investigate the role of CAV1, MCT1, and MCT4 in DCIS carcinogenesis and its association with clinicopathologic factors. Materials and methods: CAV1, MCT1, and MCT4 expression was examined in 9 pairs of DCIS tissues and matched normal adjacent tissues at mRNA and protein levels by qRT-PCR, RNAscope in situ hybridization (ISH) and immunohistochemistry. Immunohistochemical staining of CAV1, MCT1, and MCT4 was done in 79 DCIS samples with known hormone receptor (HR) and human epidermal growth factor 2 (HER2) expression using tissue microarray. Results: CAV1 mRNA expression by qRT-PCR analysis was significantly decreased in DCIS tissues compared to their corresponding normal tissues. On the other hand, MCT1 and MCT4 mRNA expression in DCIS tissues were increased compared with corresponding normal tissues and the difference was statistically significant in MCT1. Compared with their corresponding normal tissues, DCIS tissues showed decreased stromal CAV1 mRNA and protein expression and increased epithelial MCT1 and MCT4 mRNA and protein expression by ISH and immunohistochemistry. Low stromal CAV1, high epithelial MCT1, and high epithelial MCT4 expressions were observed in 29 (36.7%), 51 (64.6%) and 15 (18.9%) cases with DCIS, respectively. Low stromal CAV1 expression was significantly associated with high nuclear grade (P < 0.05). High epithelial MCT4 expression was associated with larger tumor size and HER2 positivity (P < 0.05 and P < 0.05, respectively). Although not statistically significant, low stromal CAV1 and high epithelial MCT4 expression tended to be associated with recurrence of DCIS. No associations were observed between stromal CAV1 expression and epithelial MCT 1 or MCT4 expression. Conclusions: These results suggested that changes in CAV1, MCT1, and MCT4 are associated with carcinogenesis of DCIS, and further studies are needed for their clinical usefulness. Keywords: Ductal carcinoma in situ; CAV1; MCT1; MCT4; Metabolism Citation Format: Ji Shin Lee, Nah Ihm Kim, Min Ho Park. CAV1, MCT1, and MCT4 expression in ductal carcinoma in situ of the breast and its association with clinicopathologic features [abstract]. In: Proceedings of the 2019 San Antonio Breast Cancer Symposium; 2019 Dec 10-14; San Antonio, TX. Philadelphia (PA): AACR; Cancer Res 2020;80(4 Suppl):Abstract nr P3-02-12.

Stromal Caveolin-1 and Caveolin-2 Expression in Primary Tumors and Lymph Node Metastases.

The expression of caveolin-1 (CAV1) in both tumor cell and cancer-associated fibroblasts (CAFs) has been found to correlate with tumor aggressiveness in different epithelial tumor entities, whereas less is known for caveolin-2 (CAV2). The aim of this study was to investigate the clinicopathological significance and prognostic value of stromal CAV1 and CAV2 expression in lung cancer. The expression of these two genes was investigated at protein level on a tissue microarray (TMA) consisting of 161 primary tumor samples. 50.7% of squamous cell lung cancer (SCC) tumors showed strong expression of CAV1 in the tumor-associated stromal cells, whereas only 15.1% of adenocarcinomas (AC) showed a strong CAV1 expression (p < 0.01). A strong CAV2 stromal expression was found in 46.0% of the lung tumor specimens, with no significant difference between the subtypes. Neither CAV1 nor CAV2 stromal expression was associated with any other clinicopathological factor including survival. When the stromal expression in matched primary tumors and lymph node metastases was compared, both CAV1 and CAV2 expressions were frequently found lost in the corresponding stroma of the lymph node metastasis (40.6%, p = 0.003 and 38.4%, p = 0.001, resp.). Loss of stromal CAV2 in the lymph node metastases was also significantly associated with earlier death (p = 0.011). In conclusion, in contrast to the expression patterns in the tumor tissue of lung cancer, stromal expression of CAV1 in primary tumors was not associated with clinical outcome whereas the stromal expression of especially CAV2 in the metastatic lymph nodes could be associated with lung cancer pathogenesis.

Caveolin-1 expression as a prognostic marker in triple negative breast cancers of Asian women

BackgroundTriple-negative breast cancers (TNBCs) are defined by their lack of oestrogen receptor, progesterone receptor and epidermal growth factor receptor 2. Although heterogeneous, the majority are aggressive and treatment options are...

Weak stromal Caveolin-1 expression in colorectal liver metastases predicts poor prognosis after hepatectomy for liver-only colorectal metastases

Loss of stromal Caveolin-1 (CAV1) expression is associated with poor prognosis in various cancers. We evaluated the prognostic value of CAV1 expression of both cancer cells and stromal cells in colorectal liver metastases (CRLM) in patients undergoing hepatectomy. In this retrospective study, 109 patients were enrolled. CAV1 expression was studied by immunohistochemistry. The staining was scored semiquantitatively as weak or strong. Disease-free survival (DFS) and overall survival (OS) were calculated using both Kaplan–Meier and multivariate Coxregression methods. Weak stromal CAV1 expression was associated with decreased DFS and OS in univariate and in multivariate analysis (HR 2.00; 95% CI, 1.24–3.22; P = 0.004, and HR 2.47; 95% CI, 1.28–4.76; P = 0.007, respectively). Cancer cell CAV1 expression was not associated with DFS and OS. Five-year DFS and OS rates were 13% and 43%, respectively, in patients with weak stromal CAV1 expression and 40% and 71%, respectively, in patients with strong stromal CAV1 expression. In this study, we indicate that weak stromal CAV1 expression in CRLM is an adverse prognostic factor in patients who undergo liver resection for liver-only colorectal metastases. We suggest validation of this finding in an independent cohort and consideration of risk stratification for post-hepatectomy adjuvant follow-up and therapy.

Expression of caveolin-1 in breast cancer stroma as apotential prognostic biomarker of survival andprogression: ameta-analysis.

It has been shown that caveolin-1 plays a potential role as a diagnostic and prognostic biomarker in various cancer types. The aim of the present study was to clarify whether caveolin-1 expressed in the breast cancer stroma could be aprognostic factor for breast cancer patients. We searched the PubMed, ScienceDirect and Web of Science databases for published literature investigating associations between stromal caveolin-1 expression and survival outcome in breast cancer patients. With respect to survival outcomes, the pooled hazard ratios (HRs) of caveolin-1 and the 95% confidence intervals (CI) were calculated. Our meta-analysis identified atotal of 10studies involving 2072 cases. Further investigation demonstrated that a lack of caveolin-1 expression in the breast cancer stroma is ahazard for overall survival (OS) (HR= 2.33, 95% CI: 1.57-3.46) and disease-free/progression-free survival (DFS/PFS) (HR= 3.05, 95% CI: 2.26-4.12) in breast cancer patients. Moreover, lack of caveolin-1 expression in the cancer-associated fibroblasts was asignificant predictor of DFS/PFS (HR= 2.79, 95% CI: 1.75-4.46). Our results indicated that lack of expression of caveolin-1 in the breast cancer stroma is associated with a poor prognosis.

Prognostic significance of epithelial/stromal caveolin‐1 expression in prostatic hyperplasia, high grade prostatic intraepithelial hyperplasia and prostatic carcinoma and its correlation with microvessel density

Caveolin-1 may play a role in cancer development and progression. The aim was to record the expression and localization of caveolin-1 in benign prostatic hyperplasia (BPH), high grade prostatic intraepithelial neoplasia (HGPIN) and prostatic carcinoma (PCa). Microvessel density was evaluated with CD34 immunostain. Correlations with known prognostic factors of PCa were recorded. Immunohistochemical expression of caveolin-1 and the MVD was evaluated in 65 cases; BPH (25), HGPIN (20) and PCa (20). Stromal caveolin-1expression was significantly higher in BPH than HGPIN and PCca. There was significant inverse relation between stromal caveolin-1 expression and extension to lymph node and seminal vesicle in carcinoma cases. Epithelial caveolin-1 was significantly higher in carcinomas than in BPH and HGPIN. Epithelial expression in carcinoma was significantly associated with preoperative PSA, Gleason score and lymph node extension. MVD was significantly higher in PCa than in BPH and HGPIN. There were significant relations between MVD and preoperative PSA, Gleason score, lymph node and seminal vesicle extension. Stromal caveolin-1 was associated with low MVD while epithelial caveolin-1 with high MVD. Conclusions: Caveolin-1 plays an important role in prostatic carcinogenesis and metastasis. Stromal expression of caveolin-1 in PCa is lowered in relation to BPH and HGPIN. In PCa; stromal caveolin-1 was associated with good prognostic parameters. Epithelial caveolin-1 is significantly increased in PCa than BPH and HGPIN. It is associated with clinically aggressive disease. Caveolin-1 may play a role in angiogenesis.

Loss of stromal caveolin-1 expression in colorectal cancer predicts poor survival.

To investigate the clinicopathological significance and prognostic value of caveolin-1 (CAV-1) in both tumor and stromal cells in colorectal cancer (CRC). A total of 178 patients with CRC were included in this study. The correlation between CAV-1 expression and clinicopathologic features and survival was studied. CAV-1 expression was detected in tumor and stromal cells. The expression of stromal CAV-1 was closely associated with histological type (P=0.022), pathologic tumor-node-metastasis stage (P=0.047), pathologic N stage (P=0.035) and recurrence (P=0.000). However, tumor cell CAV-1 did not show any correlation with clinical parameters. Additionally, the loss of stromal CAV-1 expression was associated with shorter disease-free survival (P=0.000) and overall survival (P=0.000). Multivariate analysis revealed that the loss of stromal CAV-1 expression was an independent prognostic factor for both overall survival (P=0.014) and disease-free survival (P=0.006). The loss of stromal CAV-1 expression in CRC was associated with poor prognosis and could be a prognostic factor for CRC patients.

Expression of caveolin-1 in peritumoral stroma is associated with histological grade in ovarian serous tumors.

Previous studies have demonstrated that Caveolin-1 (Cav-1) can ambiguously behave as tumor suppressor or tumor promoter in different neoplasms, depending on cancer type. Some findings have also revealed that cell proliferation, migration and invasion were attenuated by the knockdown of Caveolin-1 expressions. However, the functional and prognostic significance of Caveolin-1 in most tumors remains to be fully elucidated. The aim of the study was to investigate a possible association between tissue Caveolin-1 expression and the clinicopathologic features of ovarian serous tumors. Caveolin-1 expression was studied in a total of 82 formalin-fixed, paraffin-embedded specimens of ovarian serous tumors and its association with different clinicopathologic parameters was evaluated. The study included 36 (43.9%) benign, 12 (14.6%) borderline and 34 (41.5%) malignant serous tumors. Mean patient age was 43.9 ± 14.4 years (17-72 years). Statistical analysis revealed that if the tumor becomes more aggressive and invasive, it losses the stromal Caveolin-1 expression (p = 0.001). Also, parallel changes between stromal and perivascular Caveolin-1 expressions were observed. Our findings demonstrated a link between Caveolin-1 expression and the aggressiveness of ovarian cancer. Therefore, it seems safe to suggest that Cav-1 may act as a differential diagnostic biomarker in ovarian serous tumors.

Abstract B86: A cytometric atlas of the human breast: Comprehensive characterization reveals 12 distinct cell populations

Abstract The evidence for the importance of the microenvironment in regulating cell behavior and maintaining tissue architecture is clear 1-3. Given this fact, it is essential to characterize the elaborate composition of tissues, which allows us to study the elaborate and dynamic interplay among the cellular and molecular constituents. Understanding these processes and determining how they coordinate to form and maintain tissues is a key question in biology. Yet, despite all that has been learned about the breast over the years, so much remains unknown about the orchestration and functional capabilities of these elements and how and why they sometimes lead to tumor formation. Although there is general agreement to the fundamental cellular composition of the breast, newer technologies and reagents permit exploring the cellular heterogeneity with unprecedented detail and clarity. Our goal here was to develop a fluorescence-assisted cell sorting (FACS) antibody panel and comprehensive gating strategy capable of resolving every major cell type in the breast, permitting their isolation to near purity (&amp;gt;99.5%). Using extensive immunostaining of reduction mammoplasty specimens to guide panel design, we developed a method capable of resolving 12 different epithelial and stromal cell populations, including several different epithelial fractions, myoepithelial cells, fibroblasts, adipocytes, leukocytes, pericytes, erythrocytes, adipose-derived mesenchymal stem cells, and both lymphatic and capillary endothelial cells. RNA from each population has been extracted and the transcriptional profiles will be determined by RNA sequencing to confirm each population's identity and lend insight to a number of biological questions. Functional studies are also ongoing, but we have to date successfully cultured each population (excluding blood cells) for several passages, using different media and ECM substrata. Future studies will be aimed at developing heterotypic culture models using these cells, but to also use our new knowledge and experience to similarly explore the heterogeneity of ductal carcinoma in situ (DCIS) and invasive breast cancers. We will present the development of this method and characterization to date of the sorted cell populations. 1. Bissell, M.J. &amp; Hines, W.C. Why don't we get more cancer? A proposed role of the microenvironment in restraining cancer progression. Nat Med 17, 320-329 (2011). 2. Witkiewicz, A.K., Dasgupta, A., Sotgia, F., Mercier, I., Pestell, R.G., Sabel, M., Kleer, C.G., Brody, J.R. &amp; Lisanti, M.P. An absence of stromal caveolin-1 expression predicts early tumor recurrence and poor clinical outcome in human breast cancers. The American journal of pathology 174, 2023-2034 (2009). 3. Ghajar, C.M., Meier, R. &amp; Bissell, M.J. Quis custodiet ipsos custodies: who watches the watchmen? The American journal of pathology 174, 1996-1999 (2009). Citation Format: William C. Hines, Kate Thi, Maria Rojec, Gaelen Stanford-Moore, Mina J. Bissell. A cytometric atlas of the human breast: Comprehensive characterization reveals 12 distinct cell populations. [abstract]. In: Abstracts: AACR Special Conference on Cellular Heterogeneity in the Tumor Microenvironment; 2014 Feb 26-Mar 1; San Diego, CA. Philadelphia (PA): AACR; Cancer Res 2015;75(1 Suppl):Abstract nr B86. doi:10.1158/1538-7445.CHTME14-B86

Loss of stromal caveolin-1 expression: a novel tumor microenvironment biomarker that can predict poor clinical outcomes for pancreatic cancer.

AimsCancer development and progression is not only associated with the tumor cell proliferation but also depends on the interaction between tumor cells and the stromal microenvironment. A new understanding of the role of the tumor microenvironment suggests that the loss of stromal caveolin-1 (Cav-1) as a key regulator may become a potential therapy target. This study aims to elucidate whether stromal Cav-1 expression in pancreatic cancer can be a strong prognosis biomarker.MethodsTissue samples from 45 pancreatic cancer patients were studied. Parenchyma and stroma were separated and purified using laser capture microdissection. Stromal Cav-1 expression was measured from pancreatic cancer, paraneoplastic, and normal tissue using immunohistochemistry. We analyzed the correlation of stromal Cav-1 expression with clinicopathologic features and prognostic indicators, such as tumor marker HER-2/neu gene.ResultsSpecimens from six patients (13.3%) showed high levels of stromal Cav-1 staining, those from eight patients (17.8%) showed a lower, intermediate level of staining, whereas those from 31 patients (68.9%) showed an absence of staining. Cav-1 expression in cancer-associated fibroblasts was lower than that in paracancer-associated and in normal fibroblasts. Stromal Cav-1 loss was associated with TNM stage (P = 0.018), lymph node metastasis (P = 0.014), distant metastasis (P = 0.027), and HER-2/neu amplification (P = 0.007). The relationships of age, sex, histological grade, and tumor size with stromal Cav-1 expression were not significant (P>0.05). A negative correlation was found between circulating tumor cells and stromal Cav-1 expression (P<0.05).ConclusionThe loss of stromal Cav-1 in pancreatic cancer was an independent prognostic indicator, thus suggesting that stromal Cav-1 may be an effective therapeutic target for patients with pancreatic cancer.

Tumor/stromal caveolin-1 expression patterns in pleural mesothelioma define a subgroup of the epithelial histotype with poorer prognosis.

Malignant pleural mesothelioma (MPM) is a highly aggressive disease for which new prognostic biomarkers need to be identified. Caveolin-1 (CAV1), the most important member of caveolae, has been described as deregulated in MPM at the genomic level, but detailed histologic information on its distribution and prognostic role is still lacking. A series of 131 MPMs (91 epithelial, 17 biphasic, and 23 sarcomatous histotype) were investigated for CAV1 expression with immunohistochemistry and correlated with clinical-pathologic variables and outcome. CAV1 was detected in neoplastic cells of 70 (77%) of 91 epithelial, 17 (100%) of 17 biphasic, and 23 (100%) of 23 sarcomatous MPMs. Furthermore, in the epithelial group, CAV1 expression in spindle-shaped stromal cells was detected in 61 (67%) of 91 cases. The presence of stromal CAV1 expression was associated with a worse patient outcome. In MPM, CAV1 is differentially expressed according to low- to high-grade histotypes. Furthermore, in the MPM epithelial group, additional stromal CAV1 expression is associated with a worse prognosis.

Caveolin‐1 Expression in Papillary Thyroid Carcinoma: Correlation with Clinicopathological Parameters and BRAF Mutation Status

We aimed to investigate the role of caveolin-1 in papillary thyroid carcinoma pathogenesis. Case series with chart review. Institute for the Application of Nuclear Energy. We evaluated the expression of caveolin-1 in papillary thyroid carcinoma (PTC) by Western blot (WB) and compared the findings with immunohistochemical (IHC) expression of both epithelial and stromal caveolin-1 on the corresponding histological specimens. The results were related to clinicopathological features and BRAF mutation status. Caveolin-1 expression was found in malignant thyroid epithelium and more abundantly in tumor stroma but varied in both compartments within and between PTC subtypes. Caveolin-1 expression in the epithelium was more intense in classical PTC than in the other histological types. On the contrary, stromal caveolin-1 expression was stronger in the follicular, solid, and trabecular PTC variants than in classical PTC. Trends for down-regulation of caveolin-1 expression in epithelium and up-regulation in stroma from the classical via follicular to the solid variant were observed. The relation of WB and IHC results with clinicopathological parameters showed lower caveolin-1 tissue content in BRAF mutated tumors (P < .05), a positive correlation of epithelial caveolin-1 expression with lymph node metastasis (P < .05), and a negative association of stromal caveolin-1 expression with the degree of neoplastic infiltration and BRAF status. Altered expression of caveolin-1 in the thyroid epithelial and stromal compartments may be involved in the pathogenesis of PTC. The potential clinical significance of caveolin-1 expression, as well as its relation to BRAF mutation status, deserves further investigation.

Down-Regulation of Stromal Caveolin-1 Expression in Esophageal Squamous Cell Carcinoma: A Potent Predictor of Lymph Node Metastases, Early Tumor Recurrence, and Poor Prognosis

Recent studies have identified loss of stromal caveolin-1 (Cav-1) expression as a new prognostic histological characteristic in various types of human cancers. However, the clinical and pathological significance of stromal Cav-1 expression in esophageal squamous cell carcinoma (ESCC) remains largely unknown. We examined Cav-1 expression in both tumor and stromal cells in ESCC tissue by immunohistochemical analysis to evaluate its clinicopathological significance and prognostic value. A total of 110 patients with ESCC who underwent surgical resection were included in this study. The expression of Cav-1 in both tumor and stromal cells in esophageal tumor tissues was examined immunohistochemically. Cav-1 expression was found in the cytoplasm of both tumor and stromal cells. Tumor Cav-1 overexpression was observed in 37.3 % tumors, which correlated to deeper tumor invasion (p = 0.038). Down-regulation of stromal Cav-1 expression was observed in 40.9 % tumors. The stromal Cav-1 down-regulation group had more lymph node metastases and more locoregional recurrences than those with higher expression (p = 0.020 and p = 0.002, respectively). In addition, down-regulation of stromal Cav-1 expression was associated with shorter disease-free survival (p < 0.001) and overall survival (p < 0.001). Multivariate analysis revealed that down-regulation of stromal Cav-1 expression was an independent prognostic factor for both disease-free survival (p = 0.028) and overall survival (p = 0.007). Down-regulation of stromal Cav-1 expression in ESCC had high malignant potential. It predicts high-risk of lymph node metastases and locoregional recurrence, and it could be a powerful prognostic marker for patients with ESCC.

The expression and functionality of stromal caveolin 1 in human adenomyosis

What is the expression pattern and functionality of caveolin 1 (CAV1) in the endometrium of patients with adenomyosis? The stromal CAV1 expression is down-regulated that leads to the release of a variety of molecules that either enhance the metastatic capacity of endometrial cells or contribute to adenomyosis-associated dysmenorrhea. Adenomyosis is characterized by invasion of endometrium into the uterine myometrium. CAV1 has been linked to tumor progression and clinical outcome in a variety of human malignancies; however, its role in adenomyosis development and adenomyosis-associated dysmenorrhea is still poorly recognized. We retrospectively analyzed the expression levels of CAV1 and RANTES protein using immunohistochemistry in 65 patients who were pathologically diagnosed with adenomyosis and 12 control women without related pathology, who were subjected to surgery between 2009 and 2010. Endometrial tissues from six additional normal females without related pathology were collected from 2011 to 2012; these tissues were subjected to subsequent primary cell culture experiments. The expression of CAV1 and RANTES was examined by immunohistochemistry in ectopic endometrium and paired eutopic endometrium of 65 adenomyosis patients and 12 control patients. Primary endometrial stromal cells (ESCs) and endometrial epithelial cells (EECs) were isolated from 6 additional control females without related pathology. The expression of CAV1 in ESCs was either (i) inhibited by siRNA transfection and methyl-β-cyclodextrin (MβCD) treatment or (ii) increased by pcDNA3.1/CAV1 transfection. The impact of each treatment on the proliferation, migration and invasion of both ESCs and EECs was evaluated by methylthiazolydiphenyl-tetrazolium assay, colony formation assay, Transwell migration and invasion assay. Furthermore, ESC treatment with MβCD and siCAV1 was assessed for the effect on the expression of a panel of inflammatory cytokines. The levels of two pain mediators, nitric oxide (NO) and prostaglandin E2 (PGE2), were assessed in CAV-1-depleted and control ESCs, whereas immunoblotting was performed to characterize signaling pathways downstream to loss of stromal CAV1 in endometrium. The correlation between dysmenorrhea severity and stromal CAV1 and RANTES expression was further examined using 'Pearson's' correlation analysis. Stromal CAV1 expression in ectopic endometrium of adenomyosis patients was significantly lower than that of paired eutopic endometrium or normal controls as analyzed by immunohistochemistry (P < 0.001). Although no significant difference was observed in the proliferation of CAV1-depleted ESCs when compared with control group, EECs cultured with conditioned media from CAV1-depleted ESCs demonstrated a significantly elevated proliferation rate when compared with those treated with control ESC-conditioned media. Moreover, both CAV1-depleted ESCs and EECs cultured with conditioned media from CAV1-depleted ESCs showed enhanced migration and invasion capacity when compared with control group (P < 0.05). In contrast, incubation with conditioned media of ESCs with enforced CAV1 expression led to decreased proliferation capacity of EECs. Furthermore, the expression of RANTES in ESCs treated with MβCD and siCAV1 was significantly increased. Stromal RANTES expression in the ectopic endometrium of adenomyosis patients was significantly higher than that of paired eutopic endometrium or normal controls as analyzed by immunohistochemistry (P = 0.0026). Stromal CAV1 expression in eutopic endometrium was significantly lower in women with more severe dysmenorrhea (P < 0.05) and was negatively correlated with dysmenorrhea severity in adenomyosis patients (r(2) = 0.1549; P = 0.012, 'Pearson's' χ(2) test), whereas stromal RANTES expression in eutopic endometrium was significantly higher in women with more severe dysmenorrhea (P < 0.05) and was positively correlated with dysmenorrhea severity in adenomyosis patients (r(2) = 0.1646; P = 0.0094, 'Pearson's' χ(2) test). Silencing of CAV1 in ESCs led to increased release of NO and PGE2 when compared with control and was associated with enhanced activity of ERK-FAK signaling pathway. This study assessed the functional role of stromal CAV1 and RANTES in a small number of human adenomyosis samples by immunohistochemistry and in primary human ESCs by functional studies. In future investigations, a larger sample size should be adopted and the functional role of stromal CAV1 should be further characterized in animal models. Loss of stromal CAV1 expression may play a critical role in the pathogenesis of adenomyosis and is correlated with adenomyosis-related dysmenorrhea. National Basic Research Program of China and Ph.D. Programs Foundation of Ministry of Education of China. None.

Correlation of caveolin 1 expression with disease-free survival in skin melanoma.

e19016 Background: As clinical and histological parameters are unable to precisely predict the behavior of skin melanoma, new criteria are required to improve risk assessment. Caveolin 1 (CAV1), a scaffolding membrane protein, has been implicated in cell proliferation, death and transformation. In melanoma cell lines, CAV1 was found to have an antimetastatic role and loss of stromal CAV1 expression in lymph nodes metastases was associated with poor survival. The objectives of this analysis were to correlate CAV1 expression in primary skin melanoma cells with tumor thickness and disease free survival (DFS). Methods: CAV1 immunostaining was performed on the primary skin melanomas of 40 patients. CAV1 expression was scored semi-quantitatively using a 3-point scale: 0 (no staining), 1 (diffuse weak staining or strong staining in less then 30% of the cells) and 2 (strong staining of 30% or more of the cells). For analysis purposes, CAV1 was dichotomized as present (score 1 or 2) or absent (score 0). Primary melanoma was classified based on 2009 AJCC T-stage. DFS was measured from removal of primary skin melanoma to development of loco-regional or systemic recurrence. Pearson Chi-Square, Kaplan Meier, and Cox-Proportional Hazard Ratio were used for data analyses. Results: T-stage distribution was: Cis 12.5%, T1 32.5%, T2 22.5%, T3 17.5%, T4 15.0%. There was a clear inverse relationship between T stage and Cav 1 expression in tumor cells, with higher CAV1 expression in less invasive melanomas (P= 0.01). Fifteen patients experienced either locoregional or distant recurrence (median time to recurrence 14 months; range &lt;1 month -105 months). Twenty-five patients remained disease free for minimum of 3 years (median 77 months; range 36 – 111 months). Presence of CAV1 in primary melanoma tumor cells was correlated with increased DFS (P = 0.05) but this association was not significant when adjusting for T stage (P=0.59). Conclusions: CAV1 expression in melanoma tumor cells correlates with clinical behavior of skin melanoma as its loss is associated with invasiveness and distant recurrence. Whether the loss of CAV1 in primary melanoma tumor cells is just an epiphenomenon or a causal event is to be decided by further work on a larger population sample.

Stromal Caveolin-1 Expression in Breast Carcinoma. Correlation with Early Tumor Recurrence and Clinical Outcome

Caveolin- (cav-1) has been linked to tumor progression and clinical outcome in breast cancer, but its role as a prognostic marker is still unclear. We evaluated stromal and tumor caveolin-1 expression in 91 breast carcinomas, and assessed the association between their expression and clinicopathologic variables as well as patient outcome and early tumor recurrence. Absence of stromal caveolin-1 expression was detected in 18.7% of cases, while 25.3% of cases revealed tumor epithelial caveolin-1 expression. Combined stromal and tumor caveolin-1 immunopositivity was seen in 24.2% of cases. Absence of stromal cav-1 associated with larger tumor size, higher grade, higher nodal stage, higher number of positive nodes, higher TNM stage, positive HER2 status, higher recurrence rate, and shorter mean progression free survival (PFS). Stromal cav-1 status was a significant predictor of PFS in ER+, PR +, and HER2 + tumors. In tamoxifen-treated patients, absence of stromal Cav-1 was a significant predictor of poor clinical outcome, suggestive of tamoxifen resistance. Conversely, tumor epithelial and combined caveolin-1 expression, didnot associate with patient outcome. In multivariate analysis, only TNM stage independently associated with survival. Loss of stromal caveolin-1 is a novel breast cancer biomarker that can predict early tumor recurrence, short PFS, and tamoxifen- resistance. Thus, its use as a predictive biomarker, especially in lower grade, lower stage, ER+, PR+, HER2+, and tamoxifen treated patients may allow for early interventions with more aggressive therapies. Thus, stromal marker expression and epithelial-stromal cross talk may be critical for tumor progression and metastasis.

Loss of stromal caveolin-1 expression predicts poor clinical outcome in triple negative and basal-like breast cancers

Here, we investigated the possible predictive value of stromal caveolin-1 (Cav-1) as a candidate biomarker for clinical outcome in triple negative (TN) breast cancer patients. A cohort of 85 TN breast cancer patients was available, with the necessary annotation and nearly 12 years of follow-up data. Our primary outcome of interest in this study was overall survival. Interestingly, TN patients with high-levels of stromal Cav-1, had a good clinical outcome, with >50% of the patients remaining alive during the follow-up period. In contrast, the median survival for TN patients with moderate stromal Cav-1 staining was 33.5 months. Similarly, the median survival for TN patients with absent stromal Cav-1 staining was 25.7 months. A comparison of 5-year survival rates yields a similar pattern. TN patients with high stromal Cav-1 had a good 5-year survival rate, with 75.5% of the patients remaining alive. In contrast, TN patients with moderate or absent stromal Cav-1 levels had progressively worse 5-year survival rates, with 40% and 9.4% of the patients remaining alive. In contrast, in a parallel analysis, the levels of tumor epithelial Cav-1 had no prognostic significance. As such, the prognostic value of Cav-1 immunostaining in TN breast cancer patients is compartment-specific, and selective for an absence of Cav-1 staining in the stromal fibroblast compartment. A recursive-partitioning algorithm was used to assess which factors are most predictive of overall survival in TN breast cancer patients. In this analysis, we included tumor size, histologic grade, whether the patient received surgery, radiotherapy or chemotherapy, CK5/6, EGFR, p53 and Ki67 status, as well as the stromal Cav-1 score. This analysis indicated that stromal Cav-1 expression was the most important prognostic factor for overall survival in TN breast cancer. Virtually identical results were obtained with CK5/6 (+) and/or EGFR (+) TN breast cancer cases, demonstrating that a loss of stromal Cav-1 is also a strong prognostic factor for basal-like breast cancers. Our current findings may have important implications for the close monitoring and treatment stratification of TN and basal-like breast cancer patients.

Stromal Cell Expression of Caveolin-1 Predicts Outcome in Breast Cancer

Caveolin-1 has been linked to tumor progression and clinical outcome in breast cancer, but a clear resolution of its role as a prognostic marker is lacking. We assessed caveolin-1 levels in normal breast tissue and two breast cancer cohorts for which outcome data were available. We found that caveolin-1 was not expressed in normal breast luminal epithelium but was present in the epithelial compartment of some tumors. We found no association between caveolin-1 expression in the epithelial compartment and clinical outcome. However, high levels of caveolin-1 in the stromal tissue surrounding the tumor, rather than within tumor cells, associated strongly with reduced metastasis and improved survival (P < 0.0001). The onset of mammary tumors driven by Her2/neu overexpression was accelerated in mice lacking caveolin-1, thereby supporting the observation that the presence of caveolin-1 in the tumor microenvironment modulates tumor development. These studies suggest that stromal caveolin-1 expression may be a potential therapeutic target and a valuable prognostic indicator of breast cancer progression.

An Absence of Stromal Caveolin-1 Expression Predicts Early Tumor Recurrence and Poor Clinical Outcome in Human Breast Cancers

Previously, we showed that caveolin-1 (Cav-1) expression is down-regulated in human breast cancer-associated fibroblasts. However, it remains unknown whether loss of Cav-1 occurs in the breast tumor stroma in vivo. Here, we immunostained a well-annotated breast cancer tissue microarray with antibodies against Cav-1 and scored its stromal expression. An absence of stromal Cav-1 was associated with early disease recurrence, advanced tumor stage, and lymph node metastasis, resulting in a 3.6-fold reduction in progression-free survival. When tamoxifen-treated patients were selected, an absence of stromal Cav-1 was a strong predictor of poor clinical outcome, suggestive of tamoxifen resistance. Interestingly, in lymph node-positive patients, an absence of stromal Cav-1 predicted an 11.5-fold reduction in 5-year progression-free survival. Clinical outcomes among patients positive for HER2, and patients triple-negative for estrogen receptor, progesterone receptor and HER2, were also strictly dependent on stromal Cav-1 levels. When our results were adjusted for tumor and nodal staging, an absence of stromal Cav-1 remained an independent predictor of poor outcome. Thus, stromal Cav-1 expression can be used to stratify human breast cancer patients into low-risk and high-risk groups, and to predict their risk of early disease recurrence at diagnosis. Based on related mechanistic studies, we suggest that breast cancer patients lacking stromal Cav-1 might benefit from anti-angiogenic therapy in addition to standard regimens. We conclude that Cav-1 functions as a tumor suppressor in the stromal microenvironment.