miR­145­5p is associated with pathological complete response to neoadjuvant chemotherapy and impairs cell proliferation by targeting TGFßR2 in breast cancer.

Cancer patients who better benefit from neoadjuvant chemotherapy (NeoCh) are those who achieve a successful pathological complete response (pCR) represented by the absence of residual disease. Unfortunately, no highly sensitive and specific tumor biomarkers for predicting the clinical response to NeoCh have yet been defined. The aim of the present study was to ascertain whether miR­145­5p could discriminate between pCR and no­pCR in triple­negative breast cancer patients that received a cisplatin/doxorubicin­based neoadjuvant treatment. miR­145­5p expression was determined in breast tumors by quantitative RT­PCR. Our data showed that miR­145­5p had a significant low expression (P<0.005) in patients that achieved pCR in comparison to the non­responder group. Kaplan Meier analysis indicated that low levels of miR­145­5p were associated with increased disease­free survival. In addition, receiver operating characteristic (ROC) curve analysis suggested that miR­145­5p is a good predictor of pCR (P<0.003, AUC=0.7899, 95% CI, 0.6382­0.9416). Quantitative RT­PCR expression analysis also revealed that miR­145­5p was downregulated in four breast cancer cell lines relative to normal cells. To study the functions of miR­145­5p, its expression was restored in triple­negative MDA­MB­231 cells and its effects in cell proliferation were evaluated by MTT assays and in apoptosis using Annexin V experiments. Data revealed that ectopic expression of miR­145­5p resulted in a significant inhibition of cell proliferation and also induced apoptosis. Moreover, miR­145­5p led to sensitization of breast cancer cells to cisplatin therapy. In addition, western blot assays indicated that miR­145­5p downregulated the TGFßR2 protein. In conclusion, miR­145­5p could be a potential biomarker of clinical response to NeoCh in triple­negative breast cancer. Functionally miR­145­5p may regulate cell proliferation, at least in part, by targeting TGFßR2.

Loss of function of miR-342-3p results in MCT1 over-expression and contributes to oncogenic metabolic reprogramming in triple negative breast cancer.

Triple-negative breast cancer (TNBC) is a heterogeneous and aggressive neoplasia lacking the expression of hormonal receptors and human epidermal growth factor receptor-2. Accumulating evidence has highlighted the importance of miRNAs dysregulation in the establishment of cancer programs, but the functional role of many miRNAs remains unclear. The description of miRNAs roles might provide novel strategies for treatment. In the present work, an integrated analysis of miRNA transcriptional landscape was performed (N = 132), identifying the significant down-modulation of miR-342-3p in TNBC, probably because of the aberrant activity of estrogen receptor, which serves as a transcription factor of the miRNA, as demonstrated by a siRNA-knockdown approach. The enhanced expression of miR-342-3p significantly decreased cell proliferation, viability and migration rates of diverse TN cells in vitro. Bioinformatic and functional analyses revealed that miR-342-3p directly targets the monocarboxylate transporter 1 (MCT1), which promotes lactate and glucose fluxes alteration, thus disrupting the metabolic homeostasis of tumor cells. Optical metabolic imaging assay defined a higher optical redox ratio in glycolytic cells overexpressing miR-342-3p. Furthermore, we found that hypoxic conditions and glucose starvation attenuate miR-342-3p expression, suggesting a crosstalk program between these metabolic factors. Consistently, miR-342-3p down-modulation is associated with an increased MCT1 expression level and glycolytic score in human triple negative tumors. Overall, we described for the first time the regulatory activity of miR-342-3p on relevant metabolic carcinogenic pathways in TN breast cancers.

Complete sequence of the ATP6 and ND3 mitochondrial genes in breast cancer tissue of postmenopausal women with different body mass indexes.

Due to the fact that mitochondrial defects and oxidative stress have been related with obesity and breast cancer is more aggressive in women with obesity, we investigated if postmenopausal Mexican-Mestizo women with breast cancer presented somatic mutations in the sequence of the ATP6 and/or ND3 genes. Twenty one postmenopausal Mexican-Mestizo women with breast cancer who underwent mastectomy or breast conserving surgery were studied. Height and weight were used to calculate body mass index. DNA from tumor tissue samples and blood leukocytes was amplified by polymerase chain reaction and sequenced the ATP6 and ND3 mitochondrial genes. Ages ranged from 46 to 82. According to World Health Organization criteria among the 21 women, 7 had a normal BMI, 7 were overweight and 7 had obesity. In regard to the molecular study, after sequencing the coding region of ATP6 and ND3 genes of the DNA obtained from both leukocytes and tumor tissue, we did not find somatic mutations. All of the changes that we found in both genes were polymorphisms: in ATP6, we identified in ten patients 3 non-synonymous nucleotide changes and in ND3 we observed that six patients presented polymorphisms, three of them were synonymous and two non-synonymous. To our knowledge, this constitutes the first report where the complete sequence of the ATP6 and ND3 genes has been analyzed in postmenopausal Mexican-Mestizo women with breast cancer and diverse BMI. Our results differ with those reported in Caucasian and Asian populations, possibly due to ethnic differences.

[Clinical and pathological features of breast cancer in a population of Mexico]. / Características clinicopatológicas del cáncer de mama en una población de mujeres en México.

BACKGROUND: Breast cancer is the most common among women in our country, and its treatment is based on prognostic factors to categorize patients into different risk groups. In this study, the clinical and pathological features that play a role as a prognostic factor in a representative population with breast cancer in México are described. MATERIAL AND METHODS: A descriptive analysis of the clinical and pathological features of women diagnosed with breast cancer, in a period from June 2005 to May 2014; registered in a database and calculated by simple frequencies. RESULTS: A total of 4,411 patients were included, the average age at diagnosis was 53 years, 19.7% were diagnosed by mammography screening program and 80.3% derived from any signs or symptoms. Regarding the stages at diagnosis, 6.8% were carcinoma in situ, 36% at early stages (I and IIA), 45% locally advanced (IIB to IIIC), 7.7% metastatic and 3.9% unclassifiable. A 79% were ductal histology, lobular 7.8% and the rest, other types. Of ductal carcinomas, 9.1% were grade I, 54.1% grade II, and 34.6% grade III. Regarding the biological subtypes, 65.7% were luminal, 10.9% luminal Her positive, 8.7% pure Her 2 positive and 14.6% triple negative. CONCLUSION: In the present study, we described the clinical and pathologic features of a group of Mexican women with breast cancer that might reflect a national landscape, and represent the prognostic factors to determine groups of risk and treatment decisions.

Phyllodes Tumor of the Breast: 307 Treated Cases, the Largest Mexican Experience at a Single Breast Disease Institution.

BACKGROUND: Phyllodes tumor (PT) of the breast in Hispanic patients is more frequently reported with large tumors and with more borderline/malignant subtypes compared with other populations. The objective of this study was to describe characteristics of patients with PT and to identify differences among subtypes in a Mexican population. METHODS: A retrospective study was conducted on patients with PT. Sociodemographic, histopathologic, and treatment characteristics were compared among subtypes, including only surgically treated cases due the complete surgical-specimen study requirement for appropriate WHO classification. RESULTS: During 10 years, 346 PT were diagnosed; only 307 were included (305 patients), with a mean age of 41.7 yr. Self-detected lump took place in 91.8%, usually discovered 6 months previously, with median tumor size of 4.5 cm. Local wide excisions were done in 213 (69.8%) and mastectomies in 92 (30.1%). Immediate breast reconstruction took place in 38% and oncoplastic procedures in 23%. PT were classified as benign in 222 (72.3%) cases, borderline in 50 (16.2%), and malignant in 35 (11.4%), with pathological tumor size of 4.2, 5.4, and 8.7 cm, respectively (P<0.001). Patients with malignant PT were older (48 yr), with more diabetics (14.3%), less breastfeeding (37.1%), more smokers (17.1%), with more postmenopausal cases (42.9%), and older age at menopause (51.5 years) compared with the remaining subtypes (P<0.05). Relapse occurred in 8.2% of patients with follow-up. CONCLUSION: In comparison with other Hispanic publications, these Mexican patients had similar age, with smaller tumors, modestly higher benign PT, fewer malignant PT, and lower documented relapse cases.

A Nonpalpable Nodule in Ectopic Axillary Breast Tissue: Consider Phyllodes Tumor.

Benign and malignant pathology can develop in ectopic axillary breast tissue, such as fibroadenomas, phyllodes tumors, and breast cancer. We present a rare case of an asymptomatic 43-year-old woman with an axillary nodule which was identified during screening mammography within ectopic axillary breast tissue, initially considered as a suspicious lymph node. Radiologic studies were considered as Breast Imaging-Reporting Data System (BI-RADS) 4. A hyperdense, lobular, and well-circumscribed nodule was identified in mammogram while the nodule by ultrasound (US) was hypoechoic with indistinct microlobular margins, without vascularity by Doppler, and measuring 1.26 × 1 cm. Core-needle biopsy reported a fibroepithelial neoplasm. The patient was submitted to local wide-needle excision located in intraoperative radiography of the surgical specimen and margin evaluation. Final histopathological study reported a 1.8 × 1.2 cm benign phyllodes tumor, with irregular, pushing, and clear wide margins within normal ectopic breast tissue. The patient without surgical complications continued annual screening without recurrence during a follow-up that took place 24 months later.

Data set of the protein expression profiles of Luminal A, Claudin-low and overexpressing HER2(+) breast cancer cell lines by iTRAQ labelling and tandem mass spectrometry.

Breast cancer is the most common and the leading cause of mortality in women worldwide. There is a dire necessity of the identification of novel molecules useful in diagnosis and prognosis. In this work we determined the differentially expression profiles of four breast cancer cell lines compared to a control cell line. We identified 1020 polypeptides labelled with iTRAQ with more than 95% in confidence. We analysed the common proteins in all breast cancer cell lines through IPA software (IPA core and Biomarkers). In addition, we selected the specific overexpressed and subexpressed proteins of the different molecular classes of breast cancer cell lines, and classified them according to protein class and biological process. Data in this article is related to the research article "Determination of the protein expression profiles of breast cancer cell lines by Quantitative Proteomics using iTRAQ Labelling and Tandem Mass Spectrometry" (Calderón-González et al. [1] in press).

[Feasibility and cosmetic outcome of oncoplastic surgery in breast cancer treatment]. / Factibilidad y resultado estético de la cirugía oncoplástica en el tratamiento de cáncer de mama.

BACKGROUND: Breast cancer is the leading oncological cause of death in Mexican women over 25 years old. Given the need to improve postoperative cosmetic results in patients with breast cancer, oncoplastic surgery has been developed, which allows larger tumour resections and minor cosmetic alterations. OBJECTIVE: To determine the oncological feasibility and cosmetic outcome of oncoplastic surgery at the Instituto de Enfermedades de la Mama, FUCAM, AC. MATERIAL AND METHODS: A review was conducted from January 2010 to July 2013, which included patients with breast cancer diagnosis treated with conventional breast-conserving surgery or with oncoplastic surgery in the Institute of Diseases of the Breast, FUCAM AC. Clinical and histopathological parameters were compared between the two groups, and a questionnaire of cosmetic satisfaction and quality of life was applied. RESULTS: Of the 171 patients included, 95 of them were treated with conventional breast-conserving surgery and 76 with oncoplastic surgery. Pathological tumour size was significantly larger in patients treated with oncoplastic surgery (p = 0.002). There were no differences found between the groups as regards the number of patients with positive surgical margin, the rate of complications, and cosmetic satisfaction. CONCLUSION: This study demonstrates the oncological feasibility and high cosmetic satisfaction of oncoplastic surgery with minimal psycho-social impact on patients.

[Sentinel lymph node metastasis in patients with ductal breast carcinoma in situ]. / Metástasis a ganglio centinela de pacientes con carcinoma ductal in situ de la mama.

BACKGROUND: Sentinel lymph node biopsy in patients with ductal carcinoma in situ still controversial, with positive lymph node in range of 1.4-12.5% due occult invasive breast carcinoma in surgical specimen. OBJECTIVE: To know the frequency of sentimel node metastases in patients with ductal carcinoma in situ, identify differences between positive and negative cases. METHODS: Retrospective study of patients with ductal carcinoma in situ treated with sentinel lymph node biopsy because mastectomy indication, palpable tumor, radiological lesion = 5 cm, non-favorable breast-tumor relation and/or patients whom surgery could affect lymphatic flow drainage. RESULTS: Of 168 in situ carcinomas, 50 cases with ductal carcinoma in situ and sentinel lymph node biopsy were included, with a mean age of 51.6 years, 30 (60%) asymptomatic. The most common symptoms were palpable nodule (18%), nipple discharge (12%), or both (8%). Microcalcifications were common (72%), comedonecrosis pattern (62%), grade-2 histology (44%), and 28% negative hormonal receptors. Four (8%) cases had intra-operatory positive sentinel lymph node and one patient at final histo-pathological study (60% micrometastases, 40% macrometastases), all with invasive carcinoma in surgical specimen. Patients with intra-operatory positive sentinel lymph node where younger (44.5 vs 51 years), with more palpable tumors (50% vs 23.1%), and bigger (3.5 vs 2 cm), more comedonecrosis pattern (75% vs 60.8%), more indifferent tumors (75% vs 39.1%), and less cases with hormonal receptors (50% vs 73.9%), compared with negative sentinel lymph node cases, all these differences without statistic significance. CONCLUSIONS: One of each 12 patients with ductal carcinoma in situ had affection in sentinel lymph node, so we recommend continue doing this procedure to avoid second surgeries due the presence of occult invasive carcinoma.

Antecedentes: en pacientes con carcinoma ductal in situ la biopsia de ganglio centinela es motivo de controversia porque se reportan ganglios positivos en 1.4-12.5% debido al carcinoma invasor oculto en la pieza quirúrgica. Objetivo: conocer la frecuencia de metástasis en ganglio centinela en pacientes con carcinoma ductal in situ e identificar las diferencias entre los casos positivos y negativos. Material y métodos: estudio retrospectivo, transversal, analítico de pacientes con carcinoma ductal in situ a quienes se realizó una biopsia de ganglio centinela por requerir mastectomía, tener un tumor palpable, lesión radiológica = 5 cm, inadecuada relación mama-tumor o porque la escisión pudiera afectar el flujo linfático. Resultados: de 168 carcinomas in situ, se incluyeron 50 casos con carcinoma ductal in situ y biopsia de ganglio centinela, de pacientes con edad promedio de 51.6 años, 30 (60%) de ellas asintomáticas. Los signos reportados fueron: nódulo palpable (18%), secreción por el pezón (12%) o ambos (8%). Predominaron las microcalcificaciones (72%), comedonecrosis (62%) y grado histológico -2 (44%) con 28% de receptores hormonales negativos. En el estudio transoperatorio 4 (8%) pacientes tuvieron ganglio centinela positivo y un caso en estudio histopatológico definitivo (60% micrometástasis, 40% macrometástasis), todos con carcinoma invasor en la pieza quirúrgica. Las pacientes con ganglio centinela transoperatorio positivo eran más jóvenes (44.5 vs 51 años), con más tumores palpables (50 vs 23.1%), más grandes (3.5 vs 2 cm), más comedonecrosis (75 vs 60.8%), más indiferenciados (75% vs 39.1%) y menos receptores hormonales (50 vs 73.9%), que las que tenían ganglio centinela negativo, sin que estas diferencias tuvieran significación estadística. Conclusiones: puesto que 1 de cada 12 pacientes con carcinoma ductal in situ tiene afectación ganglionar en el ganglio centinela, se recomienda seguir tomando la biopsia para evitar segundas cirugías por un carcinoma invasor oculto.

Comparative proteomic profiling of triple-negative breast cancer reveals that up-regulation of RhoGDI-2 is associated to the inhibition of caspase 3 and caspase 9.

There are no targeted therapeutic modalities for triple-negative breast cancer (TNBC), thus it is associated with poor prognosis and worst clinical outcome. Here, our aim was to identify deregulated proteins in TNBC with potential therapeutic applications. Proteomics profiling of TNBC and normal breast tissues through two-dimensional electrophoresis and ESI-MS/MS mass spectrometry revealed the existence of 16 proteins (RhoGDI-2, HSP27, SOD1, DJ1, UBE2N, PSME1, FTL, SH3BGRL, and eIF5A-1) with increased abundance in carcinomas. We also evidenced for the first time the deregulation of COX5, MTPN and DB1 proteins in TNBC that may represent novel tumor markers. Particularly, we confirmed the overexpression of the Rho-GDP dissociation inhibitor 2 (RhoGDI-2) in distinct breast cancer subtypes, as well as in metastatic cell lines derived from lung, prostate, and breast cancer. Remarkably, targeted disruption of RhoGDI-2 by RNA interference induced mitochondrial dysfunction, and facilitated caspase-3 and -9 activation in two breast cancer cell lines. Moreover, suppression of RhoGDI-2 resulted in a robust sensitization of breast cancer cells to cisplatin therapy. In conclusion, we identified novel proteins deregulated in TNBC, and confirmed the overexpression of RhoGDI-2. We propose that RhoGDI-2 inhibition may be exploited as a potential therapeutic strategy along cisplatin-based chemotherapy in breast cancer. BIOLOGICAL SIGNIFICANCE: There are no useful biomarkers neither targeted therapeutic modalities for triple-negative breast cancer, which highly contributes to the poor prognosis of this breast cancer subtype. In this work, we used two-dimensional electrophoresis and ESI-MS/MS spectrometry to identify novel deregulated proteins in breast cancer tissues. Particularly, our results showed that RhoGDI-2, a protein that has been associated to metastasis and poor survival in human cancers, is overexpressed in different subtypes of breast tumors, as well as in metastatic cell lines derived from lung, prostate, and breast cancer. Our data also provided novel insights about the role of RhoGDI-2 in apoptosis through intrinsic pathway inhibition. Importantly, they suggested that targeted modulation of RhoGDI-2 levels might be a useful strategy for breast cancer therapy.

RAD50 targeting impairs DNA damage response and sensitizes human breast cancer cells to cisplatin therapy.

In tumor cells the effectiveness of anti-neoplastic agents that cause cell death by induction of DNA damage is influenced by DNA repair activity. RAD50 protein plays key roles in DNA double strand breaks repair (DSBs), which is crucial to safeguard genome integrity and sustain tumor suppression. However, its role as a potential therapeutic target has not been addressed in breast cancer. Our aim in the present study was to analyze the expression of RAD50 protein in breast tumors, and evaluate the effects of RAD50-targeted inhibition on the cytotoxicity exerted by cisplatin and anthracycline and taxane-based therapies in breast cancer cells. Immunohistochemistry assays on tissue microarrays indicate that the strong staining intensity of RAD50 was reduced in 14% of breast carcinomas in comparison with normal tissues. Remarkably, RAD50 silencing by RNA interference significantly enhanced the cytotoxicity of cisplatin. Combinations of cisplatin with doxorubicin and paclitaxel drugs induced synergistic effects in early cell death of RAD50-deficient MCF-7, SKBR3, and T47D breast cancer cells. Furthermore, we found an increase in the number of DSBs, and delayed phosphorylation of histone H2AX after cisplatin treatment in RAD50-silenced cells. These cellular events were associated to a dramatical increase in the frequency of chromosomal aberrations and a decrease of cell number in metaphase. In conclusion, our data showed that RAD50 abrogation impairs DNA damage response and sensitizes breast cancer cells to cisplatin-combined therapies. We propose that the development and use of inhibitors to manipulate RAD50 levels might represent a promising strategy to sensitize breast cancer cells to DNA damaging agents.

[Neoadjuvant Chemotherapy (NC) Response in Patients with Breast Cancer According to Immunohistochemical Intrinsic Subtypes (IHC)]. / Respuesta a la quimioterapia neoadyuvante (QTneo) según los subtipos intrínsecos determinados por inmunohistoquímica (IHQ) en pacientes con cáncer de mama.

INTRODUCTION: Breast cancer is heterogeneous, with different responses to NC even within similar histology and stages. OBJECTIVE: To evaluate clinical/pathological response to NC according to different tumor subtypes in Mexican breast cancer patients. PATIENTS AND METHODS: Retrospective study of patients with breast cancer stages II-III, and complete immunohistochemistry (IHC), such as hormonal receptors HER2 and Ki67, treated with NC and surgery. Descriptive and comparative analyses between different intrinsic subtypes were performed. RESULTS: A total of 117 patients were included with 48.6 ± 10.6 years of age, stage II (24%), and III (76%). We identified 20 (17.1%) cases of luminal A, 37 (31.6%) luminal B HER2-, 13 (11.1%) luminal B HER2+, 12 (10.3%) HER2+, and 35 (29.9%) triple negative. Clinical complete response (tumor and lymph nodes) in luminal A was 10%, in luminal B HER2- 10.8%, luminal B HER2+ 15.4%, HER2+ 25%, and in triple negative 14.3%. Conservative surgeries were done in 9 (7.7%) patients. There is a weak positive association between Ki67 expression and tumor clinical response. Pathological complete response occurred in 8 (6.83%) cases, being more frequent in luminal B HER2+ patients (23%). CONCLUSIONS: Pathological complete responses were more often in luminal B HER2+ cases.

[Impact on quality of life with breast reconstructive surgery after mastectomy for breast cancer]. / Impacto en la calidad de vida con cirugía reconstructiva posterior al tratamiento de cáncer de mama.

BACKGROUND: Breast cancer treatment leads mutilation and destruction of breast shape, with negative effects on body image and self-esteem. OBJECTIVES: Assessment on quality of life after breast reconstruction surgery, impact on sexuality, the cosmetic outcome experienced by the patient, and compare result with patients who refused breast reconstruction. MATERIAL AND METHODS: Retrospective, observational, descriptive, analytic study. We included breast cancer patients treated between April 15 2010 to April 15, 2011. Application of "The Survey Questionnaire short form Health 36" (SF-36) with valid use on Mexican population was conducted to measure quality of life, which uses 8 concepts: physical functioning, physical role, body pain, general health, vitality, social function, emotional role and mental health, the results are transferred to a scale 0 (worst health) to 100 (best health). RESULTS: 37 patients whit breast reconstruction had the inclusion criteria, mean age was 48.4 years. The score of SF-36 questionnaire in reconstructed patients was 76.8, in control group was 85.19 and mastectomy patients without reconstruction was 72.6. Among the items studied those with the greatest difference was the mental health, emotional role and social function, this means that patients with breast reconstruction are less affected in their social and sexual interaction. CONCLUSIONS: The reconstructed patients have a positive impact on quality of life slightly higher, sexuality is significantly worse in patients without breast reconstruction, it is important to inform and offer breast reconstruction because many do not require these procedures for fear or lack of information.

microRNA-18b is upregulated in breast cancer and modulates genes involved in cell migration.

microRNAs are small non-coding RNAs of ~22 nucleotides that function at post-transcriptional level as negative regulators of gene expression. Aberrant expression of microRNAs could promote uncontrolled proliferation, migration and invasion of human cancer cells. In this study, we analyzed the expression of microRNA-18b (miR-18b) in breast cancer cell lines and in a set of clinical specimens. Our results showed that miR-18b was upregulated in four out of five breast cancer cell lines and also in breast tumors. In order to identify potential gene targets, we carried out transcriptional profiling of MDA-MB-231 breast cancer cells that ectopically expressed miR-18b. Our results showed that 263 genes were significantly modulated in miR-18b-deficient cells (fold change >1.5; P≤0.05). We found that knock-down of miR-18b induced the upregulation of 55 olfactory receptor (OR) genes and nine genes (NLRP7, KLK3, OLFM3, POSTN, MAGED4B, KIR3DL3, CRX, SEMG1 and CEACAM5) with key roles in cell migration and metastasis. Consistently, we found that ectopic inhibition of miR-18b suppressed the migration of two breast cancer cell models in vitro. In conclusion, we have uncovered genes directly or indirectly modulated by miR-18b which may represent potential therapeutic targets in breast cancer. Our data also pointed out a role of miR-18b in migration of breast cancer cells.

Sequence analysis of mutations and translocations across breast cancer subtypes.

Breast carcinoma is the leading cause of cancer-related mortality in women worldwide, with an estimated 1.38 million new cases and 458,000 deaths in 2008 alone. This malignancy represents a heterogeneous group of tumours with characteristic molecular features, prognosis and responses to available therapy. Recurrent somatic alterations in breast cancer have been described, including mutations and copy number alterations, notably ERBB2 amplifications, the first successful therapy target defined by a genomic aberration. Previous DNA sequencing studies of breast cancer genomes have revealed additional candidate mutations and gene rearrangements. Here we report the whole-exome sequences of DNA from 103 human breast cancers of diverse subtypes from patients in Mexico and Vietnam compared to matched-normal DNA, together with whole-genome sequences of 22 breast cancer/normal pairs. Beyond confirming recurrent somatic mutations in PIK3CA, TP53, AKT1, GATA3 and MAP3K1, we discovered recurrent mutations in the CBFB transcription factor gene and deletions of its partner RUNX1. Furthermore, we have identified a recurrent MAGI3-AKT3 fusion enriched in triple-negative breast cancer lacking oestrogen and progesterone receptors and ERBB2 expression. The MAGI3-AKT3 fusion leads to constitutive activation of AKT kinase, which is abolished by treatment with an ATP-competitive AKT small-molecule inhibitor.

Breast cancer proteomics reveals a positive correlation between glyoxalase 1 expression and high tumor grade.

Breast cancer is the neoplasia with the highest incidence in women worldwide. Proteomics approaches have accelerated the discovery of diagnostic and prognostic biomarkers. Here, we compared the proteomic profiles of breast tumors versus non-tumoral tissues in order to identify modulated proteins, which could represent potential markers associated to clinical features. By two-dimensional electrophoresis, we detected 28 differentially expressed proteins. Among these, 21 proteins were up-regulated and 7 were down-regulated in tumors (p<0.05). Proteins were identified using LC/ESI-MS/MS tandem mass spectrometry. One protein was identified as glyoxalase 1 (GLO1), an enzyme involved in detoxification of methylglyoxal, a cytotoxic product of glycolysis. GLO1 overexpression was confirmed by western blot assays in paired normal and tumor breast tissues in clinical stages I-III, and by immunohistochemistry on tissue microarrays (TMA) comprising a cohort of 98 breast tumors and 20 healthy specimens. Results from TMA demonstrated that GLO1 is overexpressed in 79% of tumors. Interestingly, GLO1 up-regulation correlates with advanced tumor grade (p<0.05). These findings demonstrate the association of GLO1 overexpression with tumor grade and pointed out for additional studies to establish the importance of GLO1 in breast cancer.

Identification and pathway analysis of microRNAs with no previous involvement in breast cancer.

microRNA expression signatures can differentiate normal and breast cancer tissues and can define specific clinico-pathological phenotypes in breast tumors. In order to further evaluate the microRNA expression profile in breast cancer, we analyzed the expression of 667 microRNAs in 29 tumors and 21 adjacent normal tissues using TaqMan Low-density arrays. 130 miRNAs showed significant differential expression (adjusted P value = 0.05, Fold Change = 2) in breast tumors compared to the normal adjacent tissue. Importantly, the role of 43 of these microRNAs has not been previously reported in breast cancer, including several evolutionary conserved microRNA*, showing similar expression rates to that of their corresponding leading strand. The expression of 14 microRNAs was replicated in an independent set of 55 tumors. Bioinformatic analysis of mRNA targets of the altered miRNAs, identified oncogenes like ERBB2, YY1, several MAP kinases, and known tumor-suppressors like FOXA1 and SMAD4. Pathway analysis identified that some biological process which are important in breast carcinogenesis are affected by the altered microRNA expression, including signaling through MAP kinases and TP53 pathways, as well as biological processes like cell death and communication, focal adhesion and ERBB2-ERBB3 signaling. Our data identified the altered expression of several microRNAs whose aberrant expression might have an important impact on cancer-related cellular pathways and whose role in breast cancer has not been previously described.

MetastamiRs: non-coding MicroRNAs driving cancer invasion and metastasis.

MicroRNAs (miRNAs) are small non-coding RNAs of ~22 nucleotides that function as negative regulators of gene expression by either inhibiting translation or inducing deadenylation-dependent degradation of target transcripts. Notably, deregulation of miRNAs expression is associated with the initiation and progression of human cancers where they act as oncogenes or tumor suppressors contributing to tumorigenesis. Abnormal miRNA expression may provide potential diagnostic and prognostic tumor biomarkers and new therapeutic targets in cancer. Recently, several miRNAs have been shown to initiate invasion and metastasis by targeting multiple proteins that are major players in these cellular events, thus they have been denominated as metastamiRs. Here, we present a review of the current knowledge of miRNAs in cancer with a special focus on metastamiRs. In addition we discuss their potential use as novel specific markers for cancer progression.