Quantitative analysis of protein-RNA interactions in fission yeast.

Characterizing the interactions between RNAs and proteins in vivo is key to better understand how organisms regulate gene expression. Here, we describe a robust and quantitative protocol to measure specific RNA-protein interactions in a native context using RNA immunoprecipitation (RIP). We provide a comprehensive experimental framework to detect cotranslational interactions and detail the quantitative analysis of purified RNAs by PCR and high-throughput sequencing. Although we developed the protocol in fission yeast, it can be readily implemented in other yeast species. For complete details on the use and execution of this protocol, please refer to Toullec et al. (2021).

Nuclear ingression of cytoplasmic bodies accompanies a boost in autophagy.

Membrane contact sites are functional nodes at which organelles reorganize metabolic pathways and adapt to changing cues. In Saccharomyces cerevisiae, the nuclear envelope subdomain surrounding the nucleolus, very plastic and prone to expansion, can establish contacts with the vacuole and be remodeled in response to various metabolic stresses. While using genotoxins with unrelated purposes, we serendipitously discovered a fully new remodeling event at this nuclear subdomain: the nuclear envelope partitions into its regular contact with the vacuole and a dramatic internalization within the nucleus. This leads to the nuclear engulfment of a globular, cytoplasmic portion. In spite of how we discovered it, the phenomenon is likely DNA damage-independent. We define lipids supporting negative curvature, such as phosphatidic acid and sterols, as bona fide drivers of this event. Mechanistically, we suggest that the engulfment of the cytoplasm triggers a suction phenomenon that enhances the docking of proton pump-containing vesicles with the vacuolar membrane, which we show matches a boost in autophagy. Thus, our findings unveil an unprecedented remodeling of the nucleolus-surrounding membranes with impact on metabolic adaptation.

The Hsp90 cochaperone TTT promotes cotranslational maturation of PIKKs prior to complex assembly.

Phosphatidylinositol 3-kinase-related kinases (PIKKs) are a family of kinases that control fundamental processes, including cell growth, DNA damage repair, and gene expression. Although their regulation and activities are well characterized, little is known about how PIKKs fold and assemble into active complexes. Previous work has identified a heat shock protein 90 (Hsp90) cochaperone, the TTT complex, that specifically stabilizes PIKKs. Here, we describe a mechanism by which TTT promotes their de novo maturation in fission yeast. We show that TTT recognizes newly synthesized PIKKs during translation. Although PIKKs form multimeric complexes, we find that they do not engage in cotranslational assembly with their partners. Rather, our findings suggest a model by which TTT protects nascent PIKK polypeptides from misfolding and degradation because PIKKs acquire their native state after translation is terminated. Thus, PIKK maturation and assembly are temporally segregated, suggesting that the biogenesis of large complexes requires both dedicated chaperones and cotranslational interactions between subunits.

Prescription Patterns of Daratumumab in Patients with Multiple Myeloma in Underprivileged Circumstances: A Multicenter Experience in Mexico.

BACKGROUND: Despite novel therapies, multiple myeloma (MM) remains an incurable malignancy, daratumumab (DARA) being a major game changer, may be a good option for treatment. AIMED OF THE STUDY: To assess the prescription patterns of DARA in patients with MM in Mexico. METHODS: 47 patients with MM were analyzed in 13 different hospitals in Mexico. RESULTS: Five (10.5%) of patients received DARA as first line therapy, 13 (27.5%) as second line, whereas 29 (62%) received its in ≥3rd line. In 32% DARA was used in combination with dexamethasone, 64% received DARA on a triple combination, and 4% as a 4 drug combination. Eighty three percent of patients had a response, including 32% in complete remission. Progression free survival (PFS) was higher in patients in ISS stage 1, and in patients achieving ≥PR. Overall survival (OS) was lower in patients not achieving ≥PR, in patients having increased LDH, and extramedullary disease. Grade 1-2 infusion related reactions were present in 34%, and grade 3-4 neutropenia and lymphopenia in 25 and 17% of the patients. CONCLUSIONS: In Mexico, 62% of patients with MM received DARA as a third or further line of treatment. DARA employed as a doublet or triplet combination is useful in relapsed/refractory patients with tolerable adverse events.

Chaperone-mediated ordered assembly of the SAGA and NuA4 transcription co-activator complexes in yeast.

Transcription initiation involves the coordinated activities of large multimeric complexes, but little is known about their biogenesis. Here we report several principles underlying the assembly and topological organization of the highly conserved SAGA and NuA4 co-activator complexes, which share the Tra1 subunit. We show that Tra1 contributes to the overall integrity of NuA4, whereas, within SAGA, it specifically controls the incorporation of the de-ubiquitination module (DUB), as part of an ordered assembly pathway. Biochemical and functional analyses reveal the mechanism by which Tra1 specifically interacts with either SAGA or NuA4. Finally, we demonstrate that Hsp90 and its cochaperone TTT promote Tra1 de novo incorporation into both complexes, indicating that Tra1, the sole pseudokinase of the PIKK family, shares a dedicated chaperone machinery with its cognate kinases. Overall, our work brings mechanistic insights into the assembly of transcriptional complexes and reveals the contribution of dedicated chaperones to this process.

New insights into the evolutionary conservation of the sole PIKK pseudokinase Tra1/TRRAP.

Phosphorylation by protein kinases is a fundamental mechanism of signal transduction. Many kinase families contain one or several members that, although evolutionarily conserved, lack the residues required for catalytic activity. Studies combining structural, biochemical, and functional approaches revealed that these pseudokinases have crucial roles in vivo and may even represent attractive targets for pharmacological intervention. Pseudokinases mediate signal transduction by a diversity of mechanisms, including allosteric regulation of their active counterparts, assembly of signaling hubs, or modulation of protein localization. One such pseudokinase, named Tra1 in yeast and transformation/transcription domain-associated protein (TRRAP) in mammals, is the only member lacking all catalytic residues within the phosphatidylinositol 3-kinase related kinase (PIKK) family of kinases. PIKKs are related to the PI3K family of lipid kinases, but function as Serine/Threonine protein kinases and have pivotal roles in diverse processes such as DNA damage sensing and repair, metabolic control of cell growth, nonsense-mediated decay, or transcription initiation. Tra1/TRRAP is the largest subunit of two distinct transcriptional co-activator complexes, SAGA and NuA4/TIP60, which it recruits to promoters upon transcription factor binding. Here, we review our current knowledge on the Tra1/TRRAP pseudokinase, focusing on its role as a scaffold for SAGA and NuA4/TIP60 complex assembly and recruitment to chromatin. We further discuss its evolutionary history within the PIKK family and highlight recent findings that reveal the importance of molecular chaperones in pseudokinase folding, function, and conservation.

Chromatin modification factors in plant pathogenic fungi: Insights from Ustilago maydis.

Adaptation to the environment is a requirement for the survival of every organism. For pathogenic fungi this also implies coping with the different conditions that occur during the infection cycle. After detecting changes to external media, organisms must modify their gene expression patterns in order to accommodate the new circumstances. Control of gene expression is a complex process that involves the coordinated action of multiple regulatory elements. Chromatin modification is a well-known mechanism for controlling gene expression in response to environmental changes in all eukaryotes. In pathogenic fungi, chromatin modifications are known to play crucial roles in controlling host interactions and their virulence capacity, yet little is known about the specific genes they directly target and to which signals they respond. The smut fungus Ustilago maydis is an excellent model system in which multiple molecular and cellular approaches are available to study biotrophic interactions. Many target genes regulated during the infection process have been well studied, however, how they are controlled and specifically how chromatin modifications affect gene regulation in the context of infection is not well known in this organism. Here, we analyse the presence of chromatin modifying enzymes and complexes in U. maydis and discuss their putative roles in this plant pathogen in the context of findings from other organisms, including other plant pathogens such as Magnaporthe oryzae and Fusarium graminearum. We propose U. maydis as a remarkable organism with interesting chromatin features, which would allow finding new functions of chromatin modifications during plant pathogenesis.

The Hos2 Histone Deacetylase Controls Ustilago maydis Virulence through Direct Regulation of Mating-Type Genes.

Morphological changes are critical for host colonisation in plant pathogenic fungi. These changes occur at specific stages of their pathogenic cycle in response to environmental signals and are mediated by transcription factors, which act as master regulators. Histone deacetylases (HDACs) play crucial roles in regulating gene expression, for example by locally modulating the accessibility of chromatin to transcriptional regulators. It has been reported that HDACs play important roles in the virulence of plant fungi. However, the specific environment-sensing pathways that control fungal virulence via HDACs remain poorly characterised. Here we address this question using the maize pathogen Ustilago maydis. We find that the HDAC Hos2 is required for the dimorphic switch and pathogenic development in U. maydis. The deletion of hos2 abolishes the cAMP-dependent expression of mating type genes. Moreover, ChIP experiments detect Hos2 binding to the gene bodies of mating-type genes, which increases in proportion to their expression level following cAMP addition. These observations suggest that Hos2 acts as a downstream component of the cAMP-PKA pathway to control the expression of mating-type genes. Interestingly, we found that Clr3, another HDAC present in U. maydis, also contributes to the cAMP-dependent regulation of mating-type gene expression, demonstrating that Hos2 is not the only HDAC involved in this control system. Overall, our results provide new insights into the role of HDACs in fungal phytopathogenesis.

Histone deacetylases: revealing the molecular base of dimorphism in pathogenic fungi.

Fungi, as every living organism, interact with the external world and have to adapt to its fluctuations. For pathogenic fungi, such interaction involves adapting to the hostile environment of their host. Survival depends on the capacity of fungi to detect and respond to external stimuli, which is achieved through a tight and efficient genetic control. Chromatin modifications represent a well-known layer of regulation that controls gene expression in response to environmental signals. However, less is known about the chromatin modifications that are involved in fungal virulence and the specific cues and signalling pathways that target chromatin modifications to specific genes. In a recently published study, our research group identified one such regulatory pathway. We demonstrated that the histone deacetylase (HDAC) Hos2 is involved in yeast-to-hyphal transition (dimorphism) and it is associated with the virulence of the maize pathogen Ustilago maydis, the causative agent of smut disease in corn. Hos2 activates mating-type genes by directly binding to their gene bodies. Furthermore, Hos2 acts downstream of the nutrient-sensing cyclic AMP-Protein Kinase A pathway. We also found that another HDAC, Clr3, contributes to this regulation, possibly in cooperation with Hos2. As a whole, our data suggest that there is a direct link between changes in the environment and acetylation of nucleosomes within certain genes. We propose that histone acetylation is critical to the proper timing and induction of transcription of the genes encoding factors that coordinate changes in morphology with pathogenesis.

Endoplasmic reticulum glucosidases and protein quality control factors cooperate to establish biotrophy in Ustilago maydis.

Secreted fungal effectors mediate plant-fungus pathogenic interactions. These proteins are typically N-glycosylated, a common posttranslational modification affecting their location and function. N-glycosylation consists of the addition, and subsequent maturation, of an oligosaccharide core in the endoplasmic reticulum (ER) and Golgi apparatus. In this article, we show that two enzymes catalyzing specific stages of this pathway in maize smut (Ustilago maydis), glucosidase I (Gls1) and glucosidase II ß-subunit (Gas2), are essential for its pathogenic interaction with maize (Zea mays). Gls1 is required for the initial stages of infection following appressorium penetration, and Gas2 is required for efficient fungal spreading inside infected tissues. While U. maydis Δgls1 cells induce strong plant defense responses, Δgas2 hyphae are able to repress them, showing that slight differences in the N-glycoprotein processing can determine the extent of plant-fungus interactions. Interestingly, the calnexin protein, a central element of the ER quality control system for N-glycoproteins in eukaryotic cells, is essential for avoiding plant defense responses in cells with defective N-glycoproteins processing. Thus, N-glycoprotein maturation and this conserved checkpoint appear to play an important role in the establishment of an initial biotrophic state with the plant, which allows subsequent colonization.

Identification of O-mannosylated virulence factors in Ustilago maydis.

The O-mannosyltransferase Pmt4 has emerged as crucial for fungal virulence in the animal pathogens Candida albicans or Cryptococcus neoformans as well as in the phytopathogenic fungus Ustilago maydis. Pmt4 O-mannosylates specific target proteins at the Endoplasmic Reticulum. Therefore a deficient O-mannosylation of these target proteins must be responsible for the loss of pathogenicity in pmt4 mutants. Taking advantage of the characteristics described for Pmt4 substrates in Saccharomyces cerevisiae, we performed a proteome-wide bioinformatic approach to identify putative Pmt4 targets in the corn smut fungus U. maydis and validated Pmt4-mediated glycosylation of candidate proteins by electrophoretic mobility shift assays. We found that the signalling mucin Msb2, which regulates appressorium differentiation upstream of the pathogenicity-related MAP kinase cascade, is O-mannosylated by Pmt4. The epistatic relationship of pmt4 and msb2 showed that both are likely to act in the same pathway. Furthermore, constitutive activation of the MAP kinase cascade restored appressorium development in pmt4 mutants, suggesting that during the initial phase of infection the failure to O-mannosylate Msb2 is responsible for the virulence defect of pmt4 mutants. On the other hand we demonstrate that during later stages of pathogenic development Pmt4 affects virulence independently of Msb2, probably by modifying secreted effector proteins. Pit1, a protein required for fungal spreading inside the infected leaf, was also identified as a Pmt4 target. Thus, O-mannosylation of different target proteins affects various stages of pathogenic development in U. maydis.

The general transcriptional repressor Tup1 is required for dimorphism and virulence in a fungal plant pathogen.

A critical step in the life cycle of many fungal pathogens is the transition between yeast-like growth and the formation of filamentous structures, a process known as dimorphism. This morphological shift, typically triggered by multiple environmental signals, is tightly controlled by complex genetic pathways to ensure successful pathogenic development. In animal pathogenic fungi, one of the best known regulators of dimorphism is the general transcriptional repressor, Tup1. However, the role of Tup1 in fungal dimorphism is completely unknown in plant pathogens. Here we show that Tup1 plays a key role in orchestrating the yeast to hypha transition in the maize pathogen Ustilago maydis. Deletion of the tup1 gene causes a drastic reduction in the mating and filamentation capacity of the fungus, in turn leading to a reduced virulence phenotype. In U. maydis, these processes are controlled by the a and b mating-type loci, whose expression depends on the Prf1 transcription factor. Interestingly, Δtup1 strains show a critical reduction in the expression of prf1 and that of Prf1 target genes at both loci. Moreover, we observed that Tup1 appears to regulate Prf1 activity by controlling the expression of the prf1 transcriptional activators, rop1 and hap2. Additionally, we describe a putative novel prf1 repressor, named Pac2, which seems to be an important target of Tup1 in the control of dimorphism and virulence. Furthermore, we show that Tup1 is required for full pathogenic development since tup1 deletion mutants are unable to complete the sexual cycle. Our findings establish Tup1 as a key factor coordinating dimorphism in the phytopathogen U. maydis and support a conserved role for Tup1 in the control of hypha-specific genes among animal and plant fungal pathogens.

Protein glycosylation in the phytopathogen Ustilago maydis: From core oligosaccharide synthesis to the ER glycoprotein quality control system, a genomic analysis.

The corn smut fungus Ustilago maydis has, over recent decades, become established as a robust pathogenic model for studying fungi-plant relationships. This use of U. maydis can be attributed to its biotrophic host interaction, easy culture and genetic manipulation in the laboratory, and the severe disease symptoms it induces in infected maize. Recent studies have shown that normal protein glycosylation is essential for pathogenic development, but dispensable for the saprophytic growth or mating. Given the relevance of protein glycosylation for U. maydis virulence, and consequently its role in the plant pathogenesis, here we review the main actors and events implicated in protein glycosylation. Furthermore, we describe the results of an in silico search, where we identify all the conserved members of the N- and O-glycosylation pathways in U. maydis at each stage: core oligosaccharide synthesis, addition of the core oligosaccharide to nascent target proteins, maturation and extension of the core oligosaccharide, and the quality control system used by the cell to avoid the presence of unfolded glycoproteins. Finally, we discuss how these genes could affect U. maydis virulence and their biotechnological implications.

The requirement for protein O-mannosylation for Ustilago maydis virulence seems to be linked to intrinsic aspects of the infection process rather than an altered plant response.

Fungal plant pathogenesis involves complex crosstalk between fungi and their plant hosts. In the case of biotrophic fungi, the host interaction is finely controlled to maintain plant viability during infection since the fungus depends on the survival of colonized plant cells. Many proteins which participate in this process are thought to be glycosylated. Thus, defects in the glycosylation of fungal proteins might alter the normally attenuated plant response and consequently affect fungal progression. O-mannosyltransferases are responsible for adding mannose residues onto target proteins, with each O-mannosyltransferase having individual target specificities. In an earlier study, we showed that O-mannosylation is essential for Ustilago maydis virulence. We found that the loss of O-mannosyltransferase PMT4 was associated with a reduced formation frequency of the invasive morphogenic structure known as the appressorium, combined with a loss in their ability to penetrate plant cuticle. Here, we discuss the possible molecular causes of these phenotypes and present additional evidence, which argue against an alteration of plant response to fungal infection as the primary cause of the Δpmt4 phenotype.

The O-mannosyltransferase PMT4 is essential for normal appressorium formation and penetration in Ustilago maydis.

In Saccharomyces cerevisiae, the PMT, KRE2/MNT1, and MNN1 mannosyltransferase protein families catalyze the steps of the O-mannosylation pathway, sequentially adding mannoses to target proteins. We have identified members of all three families and analyzed their roles in pathogenesis of the maize smut fungus Ustilago maydis. Furthermore, we have shown that PMT4, one of the three PMT family members in U. maydis, is essential for tumor formation in Zea mays. Significantly, PMT4 seems to be required only for pathogenesis and is dispensable for other aspects of the U. maydis life cycle. We subsequently show that the deletion of pmt4 results in a strong reduction in the frequency of appressorium formation, with the few appressoria that do form lacking the capacity to penetrate the plant cuticle. Our findings suggest that the O-mannosylation pathway plays a key role in the posttranslational modification of proteins involved in the pathogenic development of U. maydis. The fact that PMT homologs are not found in plants may open new avenues for the development of fungal control strategies. Moreover, the discovery of a highly specific requirement for a single O-mannosyltransferase should aid in the identification of the proteins directly involved in fungal plant penetration, thus leading to a better understanding of plant-fungi interactions.

Guidelines for the diagnosis and management of neuropathic pain: consensus of a group of Latin American experts.

These consensus guidelines have been developed by a group of Latin American experts in pain management, to point out patterns and make practical recommendations to guide the diagnosis, identify warning signs (yellow and red flags), and establish comprehensive medical management (pharmacologic and nonpharmacologic treatment) and monitoring plans for patients enduring neuropathic pain. From the viewpoint of pharmacologic management, drugs are classified into groups according to efficacy, availability/accessibility, and safety criteria. Drugs are recommended for use depending on the disease and particular circumstances of each patient, with an approach that favors multimodal treatment while taking into consideration the idiosyncrasies of medical practice in Latin America.

[Recurrence and survival rates among early breast cancer cases with triple negative immunophenotype]. / Recurrencia y supervivencia en cáncer mamario temprano con inmunofenotipo triple-negativo.

BACKGROUND: Axillary lymph node status, hormonal receptors (HR) and HER2 expression are significant prognostic factors for early breast cancer. Triple negative immunophenotype (HER2 and HR negative) is associated with a high frequency of recurrence and lower overall survival. The objective was assess clinical behavior, recurrence and survival of patients with triple negative early breast cancer and patients with other immunophenotypes. MATERIAL AND METHODS: We carried out a retrospective study among women with stages I-IIB over 18 years with determination of HR and HER2 expression by immunohistochemical assay. We identified 5 groups: triple negative, triple positive, HER2 negative & HR positive, HER2 positive & HR negative, HER2 negative & 1 HR positive. We recorded age, date of diagnosis, clinical stage, tumor size, axillary lymph node status, ER, PR, HER2, p53, angiogenesis, Ki67, type of surgery, adjuvant treatment, time to recurrence, number and recurrence site and overall survival. RESULTS: 17 patients (15.4%) had triple negative phenotype, 14 (12.7%) triple positive, 52 (47.3%) were localized in group 3, 11 (10%) in 4 and 16 (14.5%) in group 5. Triple negative phenotype was associated with increased cellular proliferation (p < 0.000); being young (median 43 years), large tumor size (median size 2.5 cm) lower proportion of patients in stage I and high frequency of p53 positive (78.5%). We observed a high frequency of recurrence and death among the triple negative group and among the HER2 positive and HR negative cases. CONCLUSIONS: Triple negative breast cancer is more common among young women and is associated with a high frequency of recurrence and mortality. Clinical behavior among triple negative breast cancer cases is aggressive and displays a similar clinical profile that observed among HER2 positive and HR negative patients.

Garrapatas (Acari: Ixodidae) recolectadas de caninos bajo asistencia veterinaria en Maracaibo Venezuela / Ticks (Acari: Ixodidae) collected from canin es under veterinary care in Maracaibo Venezuela

Se planificó la presente investigación con la finalidad de identificar las garrapatas que parasitan a caninos que asisten al servicio de consulta externa de la Policlínica Veterinaria Universitaria de la Universidad del Zulia (PUV-LUZ) en Maracaibo, Venezuela. Para esto, se muestrearon 624 garrapatas recolectadas de 64 caninos, las cuales fueron identificadas siguiendo las claves correspondientes. El total de garrapatas recolectadas fueron identificadas como la especie Rhipicephalus sanguineus. El promedio de la intesidad de infestación fue de 9,8 garrapatas por animal (rango: 2-55). De acuerdo al sexo de la garrapata, se recuperaron 366 hembras y 258 machos. La relación sexual (macho:hembra) fue de 1:1.4. En cuanto al sexo del hospedador, las garrapatas fueron recuperadas de 33 (51 por ciento) machos y 31 (48,4 por ciento) hembras. De acuerdo a la edad del hospedador, se recolectaron garrapatas de 50 (78,1 por ciento) animales menores de un año de edad y de 14 (21,9 por ciento) caninos mayores de un año. Por otra parte, de acuerdo a la raza del canino, se obtuvieron garrapatas de 31 (48,4 por ciento) animales de razas puras y de 33 (51,6 por ciento) caninos mestizos. No se detectaron diferencias estadísticas entre la infestación de acuerdo a las variables estudiadas. La única especie identificada fue R. sanguineus, con un grado bajo infestación.

A survey was carried out to identify ticks infesting dogs presented to Veterinary Policlinic of The University of Zulia (PVU-LUZ) in Maracaibo, Venezuela. For this, were collected 624 ticks from 64 dogs, those were identified. All of them were identified as Rhipicephalus sanguineus. The mean intensity was 9.8 ticks per dog (range: 2-55). Were collected 366 ticks female and 258 ticks male. Sexual ratio (male:female) was 1:1.4. There were 33 (51.69%) male dogs parasitized and 31 (48.4%) female dogs. Infestation by age was more common in dogs younger than 1 year old (78.1%) than older dogs (21.9%). Thirty-one (48.4%) pure-breed dogs were infested while mixed-breed dogs were 33 (51.6%). Statistical differences were not detected among the infestation according to sex, age or breed of the hosts. The only identified specie was R. sanguineus with a low mean intensity.

Recurrencia y supervivencia en cáncer mamario temprano con inmunofenotipo triple-negativo / Recurrence and survival rates among early breast cancer cases with triple negative immunophenotype

Antecedentes: El estado ganglionar axilar, la expresión de los receptores hormonales y del HER2 son importantes factores pronóstico en cáncer de mama temprano. El inmunofenotipo triple negativo (HER2 y receptores hormonales negativos) se ha asociado con mayor frecuencia de recurrencia y menor tiempo de supervivencia. El objetivo de esta investigación fue evaluar el comportamiento clínico, recurrencia y supervivencia en mujeres con cáncer de mama temprano-triple negativo y otros inmunofenotipos. Material y métodos: Estudio retrospectivo de mujeres en etapas IIIB, mayores de 18 años, en quienes se determinó la expresión de la proteína HER2, receptores de estrógeno y de progesterona a través de inmunohistoquímica. Se identificaron cinco grupos: triple negativo, triple positivo, HER2 negativo y receptores hormonales positivos, HER2 positivo y receptores hormonales negativos, HER2 negativo y un receptor hormonal positivo. En cada caso se analizó la edad, fecha del diagnóstico, etapa clínica, tamaño tumoral, estado ganglionar axilar, receptores de estrógenos, progesterona, HER2, p53, angiogénesis, Ki67, tipo de cirugía realizada, tratamiento adyuvante, tiempo a la recurrencia, número y sitios de la recurrencia, así como el tiempo de sobrevida global. Resultados: 17 pacientes (15.4%) manifestaron el fenotipo triple negativo; 14 (12.7%), triple positivo; 52 (47.3%) en el grupo 3, 11 (10%) en el 4 y 16 (14.5%) en el grupo 5. El fenotipo triple negativo se asoció con proliferación celular aumentada (p<0.000), menor edad (mediana 43 años), mayor tamaño tumoral (mediana 2.5 cm) y menor proporción de pacientes en etapa I, así como mayor frecuencia de expresión positiva de la proteína p53 (78.5%). Observamos mayor frecuencia de recurrencia y de muerte en el grupo triple negativo y en HER2 positivo con receptores hormonales negativos. Conclusiones: El cáncer de mama triple negativo se presenta en mujeres jóvenes y se asocia con proliferación celular aumentada, induce mayor incidencia de recurrencia y de mortalidad. El comportamiento biológico del cáncer de mama con fenotipo triple negativo es agresivo y similar al observado en pacientes con HER2 positivo y receptores hormonales negativos.

BACKGROUND: Axillary lymph node status, hormonal receptors (HR) and HER2 expression are significant prognostic factors for early breast cancer. Triple negative immunophenotype (HER2 and HR negative) is associated with a high frequency of recurrence and lower overall survival. The objective was assess clinical behavior, recurrence and survival of patients with triple negative early breast cancer and patients with other immunophenotypes. MATERIAL AND METHODS: We carried out a retrospective study among women with stages I-IIB over 18 years with determination of HR and HER2 expression by immunohistochemical assay. We identified 5 groups: triple negative, triple positive, HER2 negative & HR positive, HER2 positive & HR negative, HER2 negative & 1 HR positive. We recorded age, date of diagnosis, clinical stage, tumor size, axillary lymph node status, ER, PR, HER2, p53, angiogenesis, Ki67, type of surgery, adjuvant treatment, time to recurrence, number and recurrence site and overall survival. RESULTS: 17 patients (15.4%) had triple negative phenotype, 14 (12.7%) triple positive, 52 (47.3%) were localized in group 3, 11 (10%) in 4 and 16 (14.5%) in group 5. Triple negative phenotype was associated with increased cellular proliferation (p < 0.000); being young (median 43 years), large tumor size (median size 2.5 cm) lower proportion of patients in stage I and high frequency of p53 positive (78.5%). We observed a high frequency of recurrence and death among the triple negative group and among the HER2 positive and HR negative cases. CONCLUSIONS: Triple negative breast cancer is more common among young women and is associated with a high frequency of recurrence and mortality. Clinical behavior among triple negative breast cancer cases is aggressive and displays a similar clinical profile that observed among HER2 positive and HR negative patients.

[Biomarkers in the prognosis and treatment response of breast cancer]. / Biomarcadores en el pronóstico y respuesta al tratamiento en cáncer mamario.

PURPOSE: To determine the prognostic value of c-erbB-2, p53, hormone receptors and angiogenesis, on recurrence free time and its relationship to treatment in breast cancer patients. METHODS: Women with histologic diagnosis of breast cancer and immunohistochemical determination of biologic factors. Clinic, histologic, molecular factors and recurrence free time were registered. RESULTS: 101 patients, ages 51.98 +/- 11.5 years. Follow-up 32.52 +/- 24.3 months. Tumor recurred in 31, (30.69%); 15 (48.33%) had tumor size above 2.1 cm, 19 (61.29%) showed positive estrogen receptors and 18 (58.07%) for progesterone; 20 (64.51%) to c-erbB-2 expression (64.51%); 18 to p53; average microvessels 24.48 +/- 17.27. Tumor size related to recurrence, p = 0.008. Kruskal-Wallis test did not show a difference when correlating survival free time and biologic factors. 24 pts. (77.41%) received hormones; 20 (64.5%) chemotherapy (61.29%); 19 (61.29%) radiotherapy. Response prediction to hormones with estrogen receptor positive, p = 0.059; to chemotherapy in angiogenesis under 40 vessels/field-0.024. CONCLUSIONS: Tumor size has prognostic implications. A clear positive tendency was observed with p53 and higher microvessel density. Estrogen receptors offer predictive response value to hormone treatment and lower vascular density to chemotherapy, treatment indicators of possible therapeutic association.