miR-30e* is an independent subtype-specific prognostic marker in breast cancer.

BACKGROUND: Breast cancer clinical outcome is affected by tumor molecular features, and the identification of subtype-specific prognostic biomarkers is relevant for breast cancer translational research. Gene expression signatures proved to be able to complement prognostic information provided by classical clinico-pathological features. Recently, microRNAs (miRNAs) have been causally linked to tumorigenesis and cancer progression and have been associated with patient outcome, also in breast cancer. METHODS: MicroRNAs associated with the development of distant metastasis were identified in a cohort of 92 ESR1+/ERBB2- lymph node-negative breast cancers from patients not receiving adjuvant treatment. Results were confirmed and further investigated in a total of 1246 miRNA and gene expression profiles of the Molecular Taxonomy of Breast Cancer International Consortium data set. Moderated t-test, univariable and multivariable Cox regression models were used for statistical analyses. RESULTS: miR-30e* was identified as independent protective prognostic factor in lymph node-negative untreated patients with ESR1+/ERBB2- tumours and retained a significant association with a good prognosis in treated patients with the same tumor subtype as well as in the ERBB2+ subtype, but not in ESR1-/ERBB2- tumours. CONCLUSIONS: We highlighted a relevant and subtype-specific role in breast cancer for miR-30e* and demonstrated that adding miRNA markers to gene signatures and clinico-pathological features can help for a better prognostication.

Analysis of plasma cytokines and angiogenic factors in patients with pretreated urothelial cancer receiving Pazopanib: the role of circulating interleukin-8 to enhance the prognostic accuracy.

BACKGROUND: Pazopanib achieved the end point of clinical activity in pretreated patients with urothelial cancer in a single-group, phase 2 trial. The objective was to identify biological predictors of clinical benefit to pazopanib in these patients. METHODS: EDTA blood samples were collected at baseline (T0) and after 4 weeks (T1) of treatment, together with radiological imaging in all 41 patients to analyse plasma circulating angiogenic factor levels by multiplex ELISA plates. Changes from T0 to T1 in marker levels were matched with response with the covariance analysis. Univariable and multivariable analyses evaluated the association with overall survival (OS), adjusted for prespecified clinical variables. Net reclassification improvement (NRI) tested the performance of the recognised Cox model. RESULTS: Increasing IL8(T1) level associated with lower response probability at covariance analysis (P=0.010). Both IL8(T0) (P=0.019) and IL8(T1) (P=0.004) associated with OS and the prognostic model, including clinical variables and IL8(T1) best-predicted OS after backward selection. The NRI for this model was 39%.When analysed as a time-varying covariate, IL8(T1) level<80 pg ml(-1) portended significantly greater response (∼80%) and 6-month OS (∼60%) probability than level ≥ 80. CONCLUSION: IL8-level changes during pazopanib allowed for a prognostic improvement and were associated with response probability.

Hepcidin and ferritin blood level as noninvasive tools for predicting breast cancer.

BACKGROUND: Currently used CA15-3 and CEA have found their clinical application particularly in the follow-up of patients with advanced disease. Novel biomarkers are urgent, especially for improving early diagnosis as well as for discriminating between benign and malignant disease. PATIENTS AND METHODS: In the present study, we used a proteomic approach based on surface-enhanced laser desorption/ionization-time of flight-mass spectrometry screening with the aim of identifying differentially expressed 2-30 kDa proteins in plasma of patients with malignant (65 cases) and benign (88 cases) breast lesions with respect to 121 healthy controls. RESULTS: We found that the most promising SELDI peaks were those corresponding to hepcidin-25 and ferritin light chain. We evaluated the capability of these peaks in predicting malignant and benign breast lesions using the area under the receiver operating characteristic curve (AUC). The results showed a good capacity to predict malignant breast lesions for hepcidin-25 [AUC: 0.82; 95% confidence interval (CI) 0.75-0.90] and ferritin light chain (AUC: 0.86; 95% CI 0.79-0.92). Conversely, a weak and satisfactory capability to predict benign breast lesion was observed for hepcidin-25 (AUC: 0.63; 95% CI 0.41-0.85) and ferritin light chain (AUC: 0.73; 95% CI 0.49-0.97). A significant association between HER2 status and hepcidin-25 was observed and the distribution of transferrin and ferritin were found significantly different in patients with breast cancer when compared with that of controls. CONCLUSIONS: This study provides evidence that hepcidin and ferritin light chain level in plasma may be of clinical usefulness to predict malignant and benign disease with respect to healthy controls.

PF-03446962, a fully-human monoclonal antibody against transforming growth-factor ß (TGFß) receptor ALK1, in pre-treated patients with urothelial cancer: an open label, single-group, phase 2 trial.

Despite a compelling preclinical rationale for the use of anti-angiogenic drugs in urothelial cancer (UC), short-living responses have been observed in clinical trials. PF-03446962 is a novel monoclonal antibody against Activin Receptor-Like Kinase-1 (ALK1), a type I subclass of the TGFß receptor, with dose-dependent anti-angiogenic activity. An open label, single-group, phase 2 trial of PF-03446962 was conducted in salvage setting. Patients failing at least one chemotherapy regimen were eligible. Design provided PF-03446962 10 mg/Kg intravenously fortnightly until disease progression (PD) or unacceptable toxicity. Two-month progression-free survival (PFS) was the primary endpoint. The trial was registered with ClinicalTrials.gov, number NCT01620970. Fourteen patients were enrolled from October 2012 to July 2013. Median age was 64 years (interquartile range [IQR]: 58.2-69.5), 9 patients had a Bellmunt score of 1-2, median number of prior drugs was 3. One stable disease and 13 PD were recorded and the study met the futility stopping rule of interim analysis. Median PFS was 1.8 months (95 %CI, 1.4-2.0). After a median follow up of 7.4 months (IQR 4.5-10.9), 8 patients are alive. Median overall survival (OS) was 8 months (95 %CI, 2.9-not estimable). Most common toxicities were thrombocytopenia (G1-2 in 5 cases, persistent G3 in one, with 3 dose delays and 1 dose interruption), fatigue and abdominal pain (G1-2 in 4 cases each). Impairment of quality of life (ESAS score) was observed as well as an increase from baseline to +2 month median levels of vascular endothelial growth factor (VEGF) and interleukin-8. PF-03446962 had no activity as single drug in refractory UC and we do not recommend further investigation outside of the combination with agents targeting the VEGF receptor axis.

Early stage breast cancer follow-up in real-world clinical practice: the added value of cell free circulating tumor DNA.

PURPOSE: Physical examinations and annual mammography (minimal follow-up) are as effective as laboratory/imaging tests (intensive follow-up) in detecting breast cancer (BC) recurrence. This statement is now challenged by the availability of new diagnostic tools for asymptomatic cases. Herein, we analyzed current practices and circulating tumor DNA (ctDNA) in monitoring high-risk BC patients treated with curative intent in a comprehensive cancer center. PATIENTS AND METHODS: Forty-two consecutive triple negative BC patients undergoing neoadjuvant therapy and surgery were prospectively enrolled. Data from plasma samples and surveillance procedures were analyzed to report the diagnostic pattern of relapsed cases, i.e., by symptoms, follow-up procedures and ctDNA. RESULTS: Besides minimal follow-up, 97% and 79% of patients had at least 1 non-recommended imaging and laboratory tests for surveillance purposes. During a median follow-up of 5.1(IQR, 4.1-5.9) years, 13 events occurred (1 contralateral BC, 1 loco-regional recurrence, 10 metastases, and 1 death). Five recurrent cases were diagnosed by intensive follow-up, 5 by symptoms, and 2 incidentally. ctDNA antedated disseminated disease in all evaluable cases excepted two with bone-only and single liver metastases. The mean time from ctDNA detection to suspicious findings at follow-up imaging was 3.81(SD, 2.68), and to definitive recurrence diagnosis 8(SD, 2.98) months. ctDNA was undetectable in the absence of disease and in two suspected cases not subsequently confirmed. CONCLUSIONS: Some relapses are still symptomatic despite the extensive use of intensive follow-up. ctDNA is a specific test, sensitive enough to detect recurrence before other methods, suitable for clarifying equivocal imaging, and exploitable for salvage therapy in asymptomatic BC survivors.

Blood-based genomics of triple-negative breast cancer progression in patients treated with neoadjuvant chemotherapy.

BACKGROUND: As neoadjuvant chemotherapy (NAC) is increasingly used in triple-negative breast cancer (TNBC), we investigated the value of circulating tumor DNA (ctDNA) for patient monitoring prior, during, and after NAC, and circulating tumor cells (CTCs) for disease characterization at clinical progression. MATERIALS AND METHODS: Forty-two TNBC patients undergoing NAC were prospectively enrolled. Primary tumor mutations identified by targeted-gene sequencing were validated and tracked in 168 plasma samples longitudinally collected at multiple time-points by droplet digital polymerase chain reaction. At progression, plasma DNA underwent direct targeted-gene assay, and CTCs were collected and analyzed for copy number alterations (CNAs) by low-pass whole genome sequencing. RESULTS: ctDNA detection after NAC was associated with increased risk of relapse, with 2-year event-free survival estimates being 44.4% [95% confidence interval (CI) 21.4%-92.3%] versus 77.4% (95% CI 57.8%-100%). ctDNA prognostic value remained worthy even after adjusting for age, residual disease, systemic inflammatory indices, and Ki-67 [hazard ratio (HR) 1.91; 95% CI 0.51-7.08]. During follow-up, ctDNA was undetectable in non-recurrent cases with the unique exception of one showing a temporary peak over eight samples. Conversely, ctDNA was detected in 8/11 recurrent cases, and predated the clinical diagnosis up to 13 months. Notably, recurrent cases without ctDNA developed locoregional, contralateral, and bone-only disease. At clinical progression, CTCs presented chromosome 10 and 21q CNAs whose network analysis showed connected modules including HER/PI3K/Ras/JAK signaling and immune response. CONCLUSION: ctDNA is not only associated with but is also predictive of prognosis in TNBC patients receiving NAC, and represents an exploitable tool, either alone or with CTCs, for personalized TNBC management.

Axillary nodal involvement by primary tumor features in early breast cancer: an analysis of 2600 patients.

BACKGROUND: Primary tumor characteristics, which are readily available to all clinicians, may aid in selecting the optimal adjuvant therapy for patients with breast cancer (BC). Herein, we investigated the relationship between tumor size, hormone receptor and HER2 status, Ki67 and age with axillary lymph node metastases (ALNM) in early-BC patients. METHODS: We analyzed data on consecutive 2600 early-BC cases collected in the registry of Fondazione IRCC Istituto Nazionale dei Tumori, Milano, Italy. Correlation between Ki67 and primary tumor size (T-size) was calculated by Spearman's rank correlation coefficient. Association of ALNM with Ki67 and other tumor characteristics was investigated by logistic regression. Adjusted odds ratios (ORs) with 95% confidence intervals (95% CIs) were estimated in all cases, and separately analyzed according to age, T-size and BC subtype. RESULTS: Large tumor size strongly associated to ALNM, with an adjusted odds ratio (OR) for each 5-mm increase of 1.32 (95% CI 1.24-1.41), except for triple-negative BC (TNBC) cases. In tumors =10 mm, without lymphovascular invasion, representing the strongest predictor of ALNM (OR 6.09, 95% CI 4.93-7.53), Ki67 resulted particularly informative, with a fourfold increased odds of ALNM for values > 30%. CONCLUSIONS: These results raise the question whether axillary node status is redundant in cases with exceptionally good features, i.e., small tumors with low Ki67, or in those candidate to adjuvant systemic treatment/radiotherapy anyway including TNBC, and support the incorporation of primary BC tumor characteristics as stratification factors in ongoing trials aiming at de-escalating axillary surgical procedures.

Apollon gene silencing induces apoptosis in breast cancer cells through p53 stabilisation and caspase-3 activation.

We analysed the effects of small interfering RNA (siRNA)-mediated silencing of Apollon, a member of the inhibitors of apoptosis protein family, on the proliferative potential and ability of human breast cancer cell lines to undergo apoptosis. In wild-type p53 ZR75.1 cells, Apollon knockdown resulted in a marked, time-dependent decline of cell growth and an increased rate of apoptosis, which was associated with p53 stabilisation and activation of the mitochondrial-dependent apoptotic pathway. Pre-incubation of cells with a p53-specific siRNA resulted in a partial rescue of cell growth inhibition, as well as in a marked reduction of the apoptotic response, indicating p53 as a major player in cell growth impairment consequent on Apollon silencing. Apollon knockdown induced consistently less pronounced anti-proliferative and pro-apoptotic effects in mutant p53 MDA-MB-231 cells than in ZR75.1 cells. Furthermore, the activation of caspase-3 seemed to be essential for the induction of apoptosis after Apollon knockdown, as the Apollon-specific siRNA had no effect on the viability of caspase-3-deficient, wild-type p53 MCF-7 cells or the ZR75.1 cells after RNA interference-mediated caspase-3 silencing. Our results indicate that p53 stabilisation and caspase-3 activation concur to determine the apoptotic response mediated by Apollon knockdown in breast cancer cells, and suggest Apollon to be a potential new therapeutic target for this malignancy.

High level of telomerase RNA gene expression is associated with chromatin modification, the ALT phenotype and poor prognosis in liposarcoma.

Telomere length is maintained by two known mechanisms, activation of telomerase or alternative lengthening of telomeres (ALT). The ALT pathway is more commonly activated in tumours of mesenchymal origin, although the mechanisms involved in the decision of a cell to activate either telomerase or ALT are unknown at present and no molecular markers exist to define the ALT phenotype. We have previously shown an association between chromatin remodelling, telomerase gene expression and ALT in cell line models. Here, we evaluate these findings and investigate their prognostic significance in a panel of liposarcoma tissue samples to understand the biology underlying the ALT phenotype. Liposarcoma samples were split into three groups: telomerase positive (Tel+); ALT positive; ALT-/Tel-. Differences in telomerase gene expression were evident between the groups with increased expression of hTR in ALT and Tel+ compared to ALT-/Tel- samples and increased hTERT in Tel+ samples only. Investigation of a small panel of chromatin modifications revealed significantly increased binding of acetyl H3 in association with hTR expression. We confirm that the presence of the ALT phenotype is associated with poor prognosis and in addition, for the first time, we show a direct association between hTR expression and poor prognosis in liposarcoma patients.

A prediction model for breast cancer recurrence after adjuvant hormone therapy.

Hormone therapy with tamoxifen has long been the established adjuvant treatment for node-positive, estrogen-receptor-positive breast cancer in postmenopausal women. Since 30-40% of these patients fail to respond, reliableoutcome prediction is necessary for successful treatment allocation. Using pathobiological variables (available in mostclinical records: tumor size, nodal involvement, estrogen and progesterone receptor content) from 596 patients recruitedat a comprehensive cancer center, we developed a prediction model which we validated in an independent cohort of 175patients recruited at a general hospital. Calculated at 3 and 4 years of follow-up, the discrimination indices were 0.716[confidence limits (CL) 0.641, 0.752] and 0.714 (CL 0.650, 0.750) for the training data, and 0.726 (CL 0.591, 0.769) and0.677 (CL 0.580, 0.745) for the testing data. Waiting for more effective approaches from genomic and proteomic studies, amodel based on consolidated pathobiological variables routinely assessed at relatively low costs may be considered as thereference for assessing the gain of new markers over traditional ones, thus substantially improving the conventional use ofprognostic criteria.

PATRI, a Genomics Data Integration Tool for Biomarker Discovery.

The availability of genomic datasets in association with clinical, phenotypic, and drug sensitivity information represents an invaluable source for potential therapeutic applications, supporting the identification of new drug sensitivity biomarkers and pharmacological targets. Drug discovery and precision oncology can largely benefit from the integration of treatment molecular discriminants obtained from cell line models and clinical tumor samples; however this task demands comprehensive analysis approaches for the discovery of underlying data connections. Here we introduce PATRI (Platform for the Analysis of TRanslational Integrated data), a standalone tool accessible through a user-friendly graphical interface, conceived for the identification of treatment sensitivity biomarkers from user-provided genomics data, associated with information on sample characteristics. PATRI streamlines a translational analysis workflow: first, baseline genomics signatures are statistically identified, differentiating treatment sensitive from resistant preclinical models; then, these signatures are used for the prediction of treatment sensitivity in clinical samples, via random forest categorization of clinical genomics datasets and statistical evaluation of the relative phenotypic features. The same workflow can also be applied across distinct clinical datasets. The ease of use of the PATRI tool is illustrated with validation analysis examples, performed with sensitivity data for drug treatments with known molecular discriminants.

A novel retinoic/butyric hyaluronan ester for the treatment of acute promyelocytic leukemia: preliminary preclinical results.

All-trans retinoic acid (ATRA) represents the therapy of choice for patients with acute promyelocytic leukemia (APL). However, patients often relapse due to ATRA-resistance. The molecular basis of APL alterations indicates that addition of a histone deacetylase inhibitor to ATRA may restore the sensitivity to retinoids. We explored the in vitro and in vivo effects of a novel retinoic/butyric hyaluronan ester (HBR) on a retinoic acid (RA)-sensitive human myeloid cell line, NB4, and on its RA-resistant subclone, NB4.007/6. In vitro, HBR induced growth arrest and terminal differentiation in RA-sensitive NB4 cells (as confirmed by an increased expression of CD11 family members and nitroblue tetrazolium assay), whereas it inhibited the growth of RA-resistant cells by apoptosis, paralleled by an increase in the levels of caspase 3 and 7. In vivo, HBR treatment of NB4-inoculated severe combined immunodeficient mice resulted in a statistically significant increase in survival time (P<0.0001), comparable to that induced by a maximum tolerated dose of RA alone. Also on P388-inoculated mice, HBR was active in contrast to RA that was completely ineffective. Present findings suggest that, owing to the simultaneous presence of RA and an histone deacetylases inhibitor, HBR might be useful in controlling the proliferation of RA-resistant cells and the differentiation of RA-sensitive cells.

Questioning the utility of pooling samples in microarray experiments with cell lines.

We describe a microarray experiment using the MCF-7 breast cancer cell line in two different experimental conditions for which the same number of independent pools as the number of individual samples was hybridized on Affymetrix GeneChips. Unexpectedly, when using individual samples, the number of probe sets found to be differentially expressed between treated and untreated cells was about three times greater than that found using pools. These findings indicate that pooling samples in microarray experiments where the biological variability is expected to be small might not be helpful and could even decrease one's ability to identify differentially expressed genes.

p53 as an independent prognostic marker in lymph node-negative breast cancer patients.

BACKGROUND: At present, most decisions concerning the use of adjuvant therapy in lymph node-negative breast cancer patients are made on the basis of traditional factors such as tumor size, nodal status, and histopathologic features. However, prognostic factors are being investigated that could identify high-risk groups and that could better address treatment efforts for those patients. Identification of more accurate prognostic markers, such as the expression of the mutant p53 protein encoded by the p53 (also known as TP53) tumor suppressor gene, that are reproducible, easily assessable, and independent in predicting clinical outcome would have a beneficial impact on cancer treatment decisions. PURPOSE: Our purpose was to analyze the predictive relevance of mutant p53 protein expression on 6-year relapse-free and overall survival in node-negative breast cancer patients in relation to menopausal status, tumor size, cell kinetics, and estrogen receptor status. METHODS: Expression of mutant p53 protein was detected by an immunohistochemical technique using a 1:50 dilution of PAb1801 monoclonal antibody on paraffin-embedded tumor specimens obtained from 256 axillary lymph node-negative breast cancer patients, with long-term follow-up (median, 72 months). The [3H]thymidine labeling index, a measure of cell kinetics, was evaluated on histologic sections after fresh tumor tissue was labeled with [3H]thymidine. Estrogen receptor status was determined by the dextran-coated charcoal absorption technique. Statistical comparisons were made for levels of p53 protein expression, [3H]thymidine labeling index, estrogen receptor status, tumor size, and menopausal status with respect to 6-year relapse-free survival and overall survival. RESULTS: Overexpression of the p53 protein, defined as the presence of more than 5% positive cells, was detected in 113 (44%) of 256 tumors. Odds ratios (ORs) for multiple regression analysis of 6-year relapse-free survival were significantly higher for p53 (OR = 3.24; 95% confidence limits [CL] = 2.01-5.23) and [3H]thymidine labeling index (OR = 1.92; 95% CL = 1.19-3.12), both of which appeared to be the most relevant indicators of relapse, than for tumor size (OR = 1.49; 95% CL = 0.94-2.38) and estrogen receptor status (OR = 0.91; 95% CL = 0.55-1.51). Overexpression was found to be unrelated to menopausal status. CONCLUSIONS: Immunohistochemically detected p53 overexpression is an independent marker for shortened 6-year relapse-free and overall survival in node-negative patients with resectable breast cancers. Based on these findings, p53 overexpression should be used with other established prognostic factors, such as [3H]thymidine labeling index and estrogen receptor status, to further refine the prognostic assessment of node-negative breast cancer.

The Bcl-2 protein: a prognostic indicator strongly related to p53 protein in lymph node-negative breast cancer patients.

BACKGROUND: The bcl-2 gene (also known as BCL2) encodes for a mitochondrial protein thought to prevent apoptosis of normal cells. The protein has been detected by immunohistochemical procedures in hormonally regulated epithelia. PURPOSE: We analyzed the predictive relevance of Bcl-2 expression on 6-year relapse-free and overall survival in lymph node-negative breast cancers in relation to pathologic (tumor size) and biologic ([3H]thymidine-labeling index, p53 protein expression, and estrogen receptor [ER] status) features. METHODS: The expression of Bcl-2 and p53 was detected by immunohistochemistry on paraffin-embedded sections from 283 node-negative resectable breast cancers treated with local-regional therapy alone until relapse. The [3H]thymidine-labeling index was evaluated on histologic sections after incubation of fresh tumor tissue with [3H]thymidine, and ER content was determined by the dextran-coated charcoal absorption technique. RESULTS: A significantly higher fraction of Bcl-2-positive cells was observed in small, ER-positive, slowly proliferating, and p53-negative tumors than in large, ER-negative, rapidly proliferating, and p53-positive tumors. A stronger association was observed between Bcl-2 and p53 expression than between these variables and [3H]thymidine-labeling index. In univariate analysis, Bcl-2 and p53 expression, [3H]thymidine-labeling index, tumor size, and ER status were indicators for relapse-free and, with the exception of tumor size, overall survival within 6 years of surgery. In multivariate analysis, Bcl-2 failed to maintain its prognostic role for relapse-free and overall survival in the presence of p53 expression, whereas the [3H]thymidine-labeling index was still statistically significant as a predictor for both events. CONCLUSION: The predictive role of Bcl-2 expression on 6-year relapse-free and overall survival was mainly dependent on p53 expression.

Expression of p53, glutathione S-transferase-pi, and Bcl-2 proteins and benefit from adjuvant radiotherapy in breast cancer.

BACKGROUND: In clinical breast cancer research, the utility of certain biomarkers as predictors of response to surgery, chemotherapy, or hormonal therapy has been studied intensively. Much less research has been done on the relevance of biologic predictors of response to radiotherapy, which represents an effective local-regional treatment for breast cancer. PURPOSE: The utility of biomarkers involved in DNA damage repair (p53 protein), control of programmed cell death (p53 and Bcl-2 proteins), and cellular detoxification (glutathione S-transferase-pi [GST-pi] enzyme) in predicting local breast cancer recurrence was analyzed retrospectively in two cohorts of breast cancer patients. These patients had had no detectable metastases in the axillary lymph nodes (i.e., node-negative) or in distant sites and had had similar distributions of clinicopathologic and biologic prognostic features. They had been treated by conservative surgery alone (139 case patients) or by conservative surgery followed by adjuvant radiotherapy (496 case patients) during the period from 1984 through 1990. METHODS: The expression of the p53, GST-pi, and Bcl-2 proteins in the specimens of primary breast tumor obtained from these patients was determined by use of immunohistochemistry; cell proliferation activity and levels of steroid receptors were determined by use of a [3H]thymidine-labeling index assay and the dextran-coated charcoal technique, respectively. The median time of follow-up of patients was 6 years. In the analyses of patient outcomes, only local failures that presented as first events were considered. RESULTS: After surgery alone, the risk of local recurrence at 6 years was higher for patients with tumors exhibiting elevated levels of p53 and GST-pi protein expression than for patients with low levels (hazard ratio [HR] = 3.1, 95% confidence interval [CI] = 1.3-7.7, two-sided P = .012; HR = 2.7, 95% CI = 1.1-6.4, two-sided P = .026, respectively). Weak or no observable expression of Bcl-2 protein was only suggestive of a higher frequency of local failures. Adjustment for patient age, tumor size, cell proliferation, and estrogen receptor status did not change these findings. Conversely, in the series of patients given conservative surgery followed by radiotherapy, there was no difference in local tumor recurrence between patients with tumors expressing or not expressing each of the three markers. CONCLUSIONS: Our study provides indirect evidence of a benefit from radiation therapy in preventing local breast cancer relapse, particularly among node-negative patients with tumors that express elevated levels of the p53 or GST-pi proteins or that express little or no Bcl-2 protein.

Exosome-mediated delivery of miR-9 induces cancer-associated fibroblast-like properties in human breast fibroblasts.

It is established that the interaction between microenvironment and cancer cells has a critical role in tumor development, given the dependence of neoplastic cells on stromal support. However, how this communication promotes the activation of normal (NFs) into cancer-associated fibroblasts (CAFs) is still not well understood. Most microRNA (miRNA) studies focused on tumor cell, but there is increasing evidence of their involvement in reprogramming NFs into CAFs. Here we show that miR-9, upregulated in various breast cancer cell lines and identified as pro-metastatic miRNA, affects the properties of human breast fibroblasts, enhancing the switch to CAF phenotype, thus contributing to tumor growth. Expressed at higher levels in primary triple-negative breast CAFs versus NFs isolated from patients, miR-9 improves indeed migration and invasion capabilities when transfected in immortalized NFs; viceversa, these properties are strongly impaired in CAFs upon miR-9 inhibition. We also demonstrate that tumor-secreted miR-9 can be transferred via exosomes to recipient NFs and this uptake results in enhanced cell motility. Moreover, we observed that this miRNA is also secreted by fibroblasts and in turn able to alter tumor cell behavior, by modulating its direct target E-cadherin, and NFs themselves. Consistently with the biological effects observed, gene expression profiles of NFs upon transient transfection with miR-9 show the modulation of genes mainly involved in cell motility and extracellular matrix remodeling pathways. Finally, we were able to confirm the capability of NFs transiently transfected with miR-9 to promote in vivo tumor growth. Taken together, these data provide new insights into the role of miR-9 as an important player in the cross-talk between cancer cells and stroma.