NME1 and DCC variants are associated with susceptibility and tumor characteristics in Mexican patients with colorectal cancer.

BACKGROUND: Colorectal cancer (CRC) ranks third in cancer incidence globally and is the second leading cause of cancer-related mortality. The nucleoside diphosphate kinase 1 (NME1) and netrin 1 receptor (DCC) genes have been associated with resistance against tumorigenesis and tumor metastasis. This study investigates the potential association between NME1 (rs34214448 G > T and rs2302254 C > T) and DCC (rs2229080 G > C and rs714 A > G) variants and susceptibility to colorectal cancer development. METHODS: Samples from 232 colorectal cancer patients and 232 healthy blood donors underwent analysis. Variants were identified using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Associations were assessed using odds ratios (OR), and the p values were adjusted with Bonferroni test. RESULTS: Individuals carrying the G/T and T/T genotypes for the NME1 rs34214448 variant exhibited a higher susceptibility for develop colorectal cancer (OR = 2.68, 95% CI: 1.76-4.09, P = 0.001 and OR = 2.47, 95% CI: 1.37-4.47, P = 0.001, respectively). These genotypes showed significant associations in patients over 50 years (OR = 2.87, 95% CI: 1.81-4.54, P = 0.001 and OR = 2.99, 95% CI: 1.54-5.79, P = 0.001 respectively) and with early Tumor-Nodule-Metastasis (TNM) stage (P = 0.001), and tumor location in the rectum (P = 0.001). Furthermore, the DCC rs2229080 variant revealed that carriers of the G/C genotype had an increased risk for develop colorectal cancer (OR = 2.00, 95% CI: 1.28-3.11, P = 0.002) and were associated with age over 50 years, sex, and advanced TNM stages (P = 0.001). CONCLUSIONS: These findings suggest that the NME1 rs34214448 and DCC rs2229080 variants play a significant role in colorectal cancer development.

Association of the rs8720 and rs12587 KRAS Gene Variants with Colorectal Cancer in a Mexican Population and Their Analysis In Silico.

Colorectal cancer (CRC) is a major global health challenge and one of the top 10 cancers in Mexico. Lifestyle and genetic factors influence CRC development, prognosis, and therapeutic response; identifying risk factors, such as the genes involved, is critical to understanding its behavior, mechanisms, and prognosis. The association between KRAS gene variants (rs8720 and rs12587) and CRC in the Mexican population was analyzed. We performed in silico analysis and analyzed 310 healthy individuals and 385 CRC patients using TaqMan assays and real-time PCR. The CC and GG genotypes of rs8720 and rs12587 were identified as CRC risk factors (p < 0.05). The CC and TC genotypes of the rs8720 were associated with rectal cancer, age over 50 years, moderately differentiated histology, and advanced cancer stage. TG and GG genotypes of the rs12587 variant were a risk factor in the CRC group, in patients with stage I-II, males, and stage III-IV non-chemotherapy response. The TG haplotype is protected against CRC. The combined CCGG genotype was linked to CRC risk. In silico analysis revealed that the rs12587 and rs8720 variants could influence KRAS gene regulation via miRNAs. In conclusion, rs8720 and rs12587 variants of the KRAS gene were associated with CRC risk and could influence KRAS regulation via miRNAs.

Functional Variants in MicroRNAs (rs895819, rs11614913 and rs2910164) Are Associated with Susceptibility and Clinicopathological Features in Mexican Patients with Colorectal Cancer.

BACKGROUND: miRNAs are non-coding RNAs participating actively in the post-translational regulation of oncogenes, tumor suppressor, and DNA repair genes implicated in colorectal cancer (CRC). This study aims to examine the association of the variants miR-27a (rs895819 A>G), miR-196a2 (rs11614913 T>G) and miR-146a (rs2910164 C>G) in Mexican CRC patients. METHODS: DNA samples from 183 patients and 186 healthy Mexican subjects were analyzed. Variants were identified by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) and adjusted by the Bonferroni test. RESULTS: Patients carrying the G/G genotype of the rs895819 variant in the miR-27a gene showed an increased risk of CRC (19% vs 12%, P=0.013). A similar tendency was noticed for patients younger than 50 years carrying A/G (48% vs 41%, P=0.014). The A/G genotype in TNM stages I+II (55.7% vs 40.8%, P=0.011) and tumor location in the colon (69.5 vs 40.8%, P=0.001) were also increased. For the variant rs11614913 of the miR-196a2 gene, carriers of the C/C genotype showed an increased risk of CRC (32% vs 22%, P=0.009). This genotype was more frequent in TNM stage III+IV (36.8% vs 22.5%, P=0.007) and the tumor had a more recurrent location in the rectum (31.6% vs 22.5%, P=0.013). The rs2910164 variant of the miR-146a gene was found to have no significant risk associations. CONCLUSION: Our results reveal that the rs895819 variant in miR-27a and rs11614913 in miR-196a2 have a substantial impact on the development of CRC.

Circulating cell-free-DNA concentration is a good biomarker for diagnosis of colorectal cancer in Mexican patients.

Colorectal cancer (CRC) is the third most common cancer in the world. Overall survival is related to clinical stage: more advanced stages show lower survival rates; therefore, they need to be monitored regularly with new, less invasive and more specific biomarkers. The concentration and integrity index of circulating cell-free DNA (ccfDNA) have been proposed as potential diagnostic and prognostic biomarkers for CRC, however, inconsistent results are still observed in different reports. Here we analyze these potential CRC biomarkers in a Mexican population. In this study, 124 patients with sporadic CRC and 37 healthy individuals were examined as a reference group. The ccfDNA was isolated from plasma samples of all included subjects. The ccfDNA concentration was determined by fluorometry and the integrity index (ALU247/ALU115 ratio) by quantitative PCR amplification (qPCR) of ALU sequences. The results show that ccfDNA concentration was higher in CRC patients than in the reference group (P=0.001). The integrity index showed no significant differences between these groups (P=0.258), except for histological type (P=0.012). A higher ccfDNA concentration was also associated with patients younger than 50 years (P=0.030). The ccfDNA concentration showed significant discriminatory power (AUC: 0.854, C.I.: 0.78-0.92, P=0.001) between patients and the reference group and between tumor-node-metastasis (TNM) stages. In conclusion, ccfDNA concentration proves to be a good diagnostic biomarker for CRC patients, whereas the integrity index did not show diagnostic utility.

ESR2 gene variants (rs1256049, rs4986938, and rs1256030) and their association with breast cancer risk.

Background: Variants of the estrogen receptor b (ESR2) gene have been associated with different types of cancer. However, these associations have been inconsistent. We genotyped the ESR2 variants (rs1256049, rs4986938, and rs1256030) in breast cancer (BC) patients and in healthy women. Results: The variants rs1256049 and rs4986938 in the ESR2 gene were not associated with risk susceptibility in BC patients. However, the rs1256030 variant had an association as a risk factor for BC patients when compared with controls and BC patients for the TT genotype (odds ratio (OR) 1.86, 95% confidence intervals (CI) [1.05-3.28], p = 0.042). In addition, differences were observed in patients and controls carrying the TT genotype under 50 years of age (OR 1.85, 95% CI [1.05-3.27], p = 0.043). Thus, evident differences showed the rs1256030 variant in patients with TT, TC, and TC+TT genotypes with: (1) Stage IV (OR 1.60, 95% CI [1.06-2.54], p = 0.033), and (2) Luminal A (OR 1.60, 95% CI [0.47-0.21], p = 0.041), as well as in BC carriers of the TT genotype with indices of cellular proliferative (Ki-67) elevated (>20%) and overweight (OR 1.67, 95% CI [0.85-3.28], p = 0.041), respectively. In BC HER2 with lymph node metastasis, the TT genotype was a protective factor (OR 0.38, 95% CI [0.18-0.78], p = 0.005). The identification of haplotypes included two common GAT as risk factors (OR 3.1, 95% CI [1.31-7.72], p = 0.011) and GGC as a protective factor (OR 0.7, 95% CI [0.60-0.97], p = 0.034). The haplogenotype GGGATC was a risk factor (OR 2.5, 95% CI [1.28-5.0], p = 0.008). Conclusion: The variant rs1256030 (TT) of the ESR2 gene and haplotype GAT were associated with susceptibility to BC as risk factors in this sample from the Mexican population.

MKK4 variants rs3826392 and rs3809728 are associated with susceptibility and clinicopathological features in colorectal cancer patients.

OBJECTIVES: The mitogen-activated protein kinase kinase 4 (MKK4) plays a key role in several processes like inflammation, apoptosis, and tumorigenesis. Several authors have proposed that genetic variations in these genes may alter their expression with subsequent cancer risk. This study aimed to examine the possible association of MKK4 rs3826392 and rs3809728 variants in Mexican patients with colorectal cancer (CRC). These variants were also compared with clinical features as sex, age, TNM stage, and tumor location. MATERIALS AND METHODS: The study included genomic DNA from 218 control subjects and 250 patients. Genotyping of the MKK4 variants was performed using polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) procedure. RESULTS: Individuals with A/T and T/T genotypes for the rs3809728 (-1044 A>T) variant showed a significantly increased risk for CRC (P=0.012 and 0.007, respectively); while individuals with the G/G genotype for the rs3826392 (-1304 T>G) variant showed a decreased risk for CRC (P=0.012). Genotypes of the MKK4 rs3809728 variant were also significantly related to colon localization and advanced TNM stage in CRC patients. T-T haplotype (rs3826392 and rs3809728) of the MKK4 gene was associated with risk in patients with CRC. CONCLUSION: The rs3826392 variant in the MKK4 gene could be a cancer protective factor, while the rs3809728 variant could be a risk factor. These variants play a significant role in CRC risk.

Protective effect of rs712 polymorphism in a let-7 microRNA-binding of KRAS gene in breast cancer of a Mexican population.

PURPOSE: The rs712 polymorphism in a let-7 microRNA-binding KRAS gene has been associated with different types of cancer, however these associations have been inconsistent. The purpose of this study was to determine the association between rs712 polymorphism in a let-7 microRNA-binding KRAS gene comparing breast cancer (BC) patients with healthy subjects from Mexican population. METHODS: The genotyping of the rs712 polymorphism was performed by polymerase chain reaction (PCR) in 437 BC patients and 414 healthy women. RESULTS: The observed frequencies of the rs712 polymorphism indicated an associated protective factor for BC in the dominant GT+TT model [odds ratio (OR) 0.70, 95% confidence interval (CI) 0.51-0.97, p=0.040). An association between genotype and BC patients was evident in chemotherapy response (allele GT, OR 0.032, 95% CI 0.002-0.505, p=0.014), partial chemotherapy response (genotype GT, OR 0.023, 95% CI 0.001-0.419, p=0.011), and gastric and hematological toxicity (genotype GT, OR 0.115, 95% CI 0.028-0.473, p=0.003), Luminal A BC patients with gastric and hematological toxicity (genotype TT, OR 0.236, 95% CI 0.069-0.805, p=0.021) and tobacco consumption (genotype TT, OR 0.283, 95% CI 0.001-0.802, p=0.037) and Luminal B with metastatic lymph node (genotype GT, OR 0.241, 95% CI 0.093-0.626, p=0.003). CONCLUSION: Polymorphism rs712 in KRAS gene was protective factor associated with susceptibility for BC in this sample from Mexican population.

CD44 Genotypes Are Associated with Susceptibility and Tumor Characteristics in Colorectal Cancer Patients.

Colorectal cancer is the third cause of cancer and the second leading cause of death worldwide. The CD44 gene plays a key role in malignant processes, including growth, survival, epithelial to mesenchymal transition and metastasis. It is also known that some variants as rs187116 (c.67+4883G>A) and rs7116432 (c.2024+779A>G) can modulate the function of the CD44 gene and malignant transformation in several neoplasms. This study aims to explore, for the first time, the association of the CD44 rs187116 and rs7116432 variants in patients with colorectal cancer. Genomic DNA from 250 patients and 250 healthy blood donors were analyzed. The identification of variants was made by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) test and multivariate analysis. Individuals carrying the G/A and A/A genotypes for the rs187116 polymorphism showed an increased risk for colorectal cancer (OR = 3.11, 95% CI: 1.87-5.16, P = 0.001 and OR = 3.59, 95% CI: 2.06-6.25, P = 0.001, respectively). After adjusting for age and gender, these same genotypes and the G/G genotype of the rs7116432 polymorphism were associated with TNM stage and tumor location in the colon. Moreover, the A-G (rs187116 and rs7116432) haplotype was associated with increased risk; while, the haplotype G-A (rs187116 and rs7116432) was related with decreased risk. In conclusion, our results suggest that the here analyzed CD44 variants are involved with risk, TNM stage and tumor location in colorectal cancer.

GSK3ß Polymorphisms Are Associated with Tumor Site and TNM Stage in Colorectal Cancer.

BACKGROUND: Mutations and polymorphisms of the GSK3ß gene have been associated with several diseases including Alzheimer disease, diabetes and cancer; however, to date, no variants of this gene have been associated with colorectal cancer (CRC). This study aims to explore, for the first time, the association of the GSK3ß rs334558 and rs6438552 polymorphisms with CRC. METHODS: Genomic DNA from 330 CRC patients and healthy blood donors were analyzed. Identification of polymorphisms was made by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) test. RESULTS: Patients carrying the C/T genotype for the rs334558 (T>C) polymorphism showed an increased risk for CRC (OR = 1.71, 95% CI: 1.05-2.79, P = 0.039); this association was also observed for TNM stage and tumor location. For the rs6438552 (T>C) polymorphism, the OR analysis showed that patients carrying C/T and C/C genotypes have a decreased risk for CRC (OR = 0.44, 95% CI: 0.27-0.70, P = 0.001 and OR = 0.24, 95% CI: 0.10-0.64, P = 0.001, respectively); this decreased risk was also evident in the stratified analysis by TNM stage and tumor location. Haplotype analysis of these 2 loci of GSK3ß (rs334558 and rs6438552) showed differential distribution. The T-T and C-C haplotype was associated with a decreased risk of CRC, while the T-C haplotype was associated with an increased risk of CRC. CONCLUSION: Our results denote that GSK3ß gene polymorphisms play a significant role in promoting or preventing CRC. Additionally, variations in this gene are associated with the tumor site and the tumor-node-metastasis (TNM) stage in these patients.

Genetic Polymorphisms in APC, DVL2, and AXIN1 Are Associated with Susceptibility, Advanced TNM Stage or Tumor Location in Colorectal Cancer.

Colorectal cancer (CRC) is the third most common cancer and the second leading cause of death worldwide. The named "destruction complex" has a critical function in the Wnt/ß-catenin pathway regulating the level of ß-catenin in the cytoplasm and nucleus. Alterations in this complex lead to the cellular accumulation of ß-catenin, which participates in the development and progression of CRC. This study aims to determine the contribution of polymorphisms in the genes of the ß-catenin destruction complex to develop CRC, specifically adenomatous polyposis coli (APC) (rs11954856 G>T and rs459552 A>T), axis inhibition protein 1 (AXIN1) (rs9921222 C>T and rs1805105 C>T), AXIN2 (rs7224837 A>G), and dishevelled 2 (DVL2) (2074222 G>A and rs222836 C>T). Genomic DNA from 180 sporadic colorectal cancer patients and 150 healthy blood donors were analyzed. The identification of polymorphisms was made by polymerase chain reaction followed by restriction fragment length polymorphism (PCR-RFLP) methodology. Association was calculated by the odds ratio (OR) test. Increased susceptibility to CRC was associated with the polymorphic variants rs11954856 (APC), rs222836 (DVL2), and rs9921222 (AXIN1). Decreased susceptibility was associated with the polymorphisms rs459552 (APC) and 2074222 (DVL2). Association was also observed with advanced Tumor-Node-Metastasis (TNM) stages and tumor location. The haplotypes G-T in APC (rs11954856-rs459552) and A-C in DVL2 (rs2074222-rs222836) were associated with decreased risk of CRC, while the G-T haplotype in the DVL2 gene was associated with increased CRC risk. In conclusion, our results suggest that variants in the destruction complex genes may be involved in the promotion or prevention of colorectal cancer.

Association of rs712 polymorphism in a let-7 microRNA-binding site of KRAS gene with colorectal cancer in a Mexican population.

OBJECTIVES: The rs712 polymorphism in a let-7 microRNA-binding site at KRAS gene has been associated with cancer. To examine its association with rs712 polymorphism, we analyzed Mexican individuals with colorectal cancer (CRC) and healthy subjects. MATERIALS AND METHODS: Genotyping of the rs712 polymorphism was performed by polymerase chain reaction in 281 controls and 336 CRC patients. RESULTS: The observed frequencies of rs712 polymorphism indicated an associated protective factor for CRC (P=0.032). An association between genotype and the disease was evident in: colon localization (allele T, odds ratio (OR) 3.82, 95% confidence Intervals (CI) 2.77-5.28, P=0.0001), node metastasis (genotype TT, OR 2.49, 95% CI 1.45-4.28, P=0.0009), poor differentiation (genotype GT, OR 2.35, 95% CI 1.35-4.1, P=0.0033), and poor chemotherapy response (genotype GT, OR 2.6, 95% CI 1.7-4.24, P=0.0001). CONCLUSION: Comparison of the data from patients with control group showed that polymorphism of rs712 in KRAS gene was protective factor, which was associated with susceptibility for CRC. However, the genotypes TT and GT of rs712 polymorphism in KRAS could contribute significantly to colon localization, node metastasis, poor differentiation and poor chemotherapy response in CRC patients in this sample population.

[Use of micro RNAs in the diagnosis and prognosis of colorectal cancer (CCR)]. / Utilidad de los microARN en el diagnóstico y pronóstico del cáncer colorrectal (CCR).

The aim of this review is to present a general overview about the importance of micro RNAs (miRNAs) in colorectal carcinoma. First, we focused on the mechanisms whereby the miRNAs regulate the expression of target genes, and how an altered regulation of them is associated with several types of cancer, including colorectal carcinoma. Later, examples of some miRNAs that have been associated with cancer development and how the expression patterns of specific miRNAs can be used as potential biomarkers for prognosis, diagnosis and therapeutic outcome in colorectal carcinoma are addressed. Finally, several polymorphisms presents in the miRNAs that have been associated to risk and prognosis in colorectal carcinoma are described.

AXIN2 Polymorphisms and Their Association with Colorectal Cancer in Mexican Patients.

AIM: The aim of this study was to investigate the association of the rs2240308 and rs1133683 polymorphisms in the AXIN2 gene with colorectal cancer (CRC) in Mexican patients. MATERIALS AND METHODS: Genomic DNAs from 201 CRC patients and 100 healthy blood donors were analyzed for AXIN2 gene polymorphisms by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP) methodology. Statistical associations were calculated using the odds ratio (OR) test. RESULTS: The genotype distribution of the rs1133683 polymorphism C > T showed a statistical difference between the two study groups (p = 0.0019). Moreover, OR analyses demonstrated that individuals with either the C/T or T/T genotype have a decreased risk for CRC compared with individuals with the C/C genotype (OR = 0.47, 95% confidence interval [CI] = 0.25-0.86, p = 0.0134 and OR = 0.24, 95% CI = 0.10-0.57, p = 0.005, respectively). This association was also evident in a stratified analysis based on tumor-node-metastasis (TNM) stage. For the rs2240308 polymorphism C > T, the OR analysis showed a significantly increased risk for carriers of the T/T genotype (OR = 2.64, 95% CI = 1.12-6.24, p = 0.0236) and this association was also evident in the stratified analysis by TNM stage. CONCLUSION: Our results indicate the possibility that variations in the AXIN2 gene may play a significant role in promoting or preventing CRC development.

[Colorectal cancer (CCR): genetic and molecular alterations]. / Cáncer colorrectal (CCR): alteraciones genéticas y moleculares.

The aim of this review is to present a genetic and molecular overview of colorectal carcinogenesis (sporadic and hereditary origin) as a multistage process, where there are a number of molecular mechanisms associated with the development of colorectal cancer and genomic instability that allows the accumulation of mutations in proto-oncogenes and tumor suppressor genes, chromosomal instability, and methylation and microsatellite instability, and the involvement of altered expression of microRNAs' prognosis factors.

[Alzheimer's disease and fragile X syndrome: the Wnt/ß-catenin pathway as a common biological mechanism]. / Enfermedad de Alzheimer y síndrome X frágil: la vía Wnt-ß-catenina como mecanismo biológico común.

INTRODUCTION: Various disorders affecting the canonical Wnt/ß-catenin signalling pathway have been related to the activation or inactivation of oncogenes and tumour suppressor genes that give rise to a number of well-defined neoplasias, as well as several genes involved in a growing group of complaints, including Alzheimer's disease (AD) and fragile X syndrome (FXS). AIM: To examine the Wnt/ß-catenin signalling pathway as a possible common biological mechanism involved in the origin and development of neurodegenerative conditions and its relationship with cancer. DEVELOPMENT: We review the most recent biomedical literature dealing with the Wnt/ß-catenin signalling pathway and its participation in the genesis of complaints such as AD and FXS. An analysis is also conducted to determine the role that this metabolic pathway might play in explaining the lowered risk of developing cancer displayed by these patients. CONCLUSIONS: The evidence found suggests that the Wnt/ß-catenin pathway could be regulating a set of genes linked with the control of the cell cycle and apoptosis. This would give rise to a metabolic state in which, in conditions such as AD and FXS, the cells would be more likely to undergo apoptosis than initiate mitosis, which would in turn account for the reduced risk of developing cancer.

Enfermedad de Alzheimer y síndrome X frágil: la vía Wnt-ß-catenina como mecanismo biológico común / Alzheimer's disease and fragile X syndrome: the Wnt/β - catenin pathway as a common biological mechanism

Introducción. Diversas alteraciones en la vía de señalización canónica Wnt-β-catenina se han relacionado con la activación o inactivación de oncogenes y genes supresores de tumor que dan lugar a múltiples neoplasias bien caracterizadas, así como de varios genes implicados en un grupo creciente de padecimientos, entre los que se incluyen la enfermedad de Alzheimer (EA) y el síndrome X frágil (SXF). Objetivo. Examinar la vía de señalización Wnt-β-catenina como un posible mecanismo biológico común involucrado en el origen y desarrollo de padecimientos neurodegenerativos y su relación con el cáncer. Desarrollo. Se revisa en la literatura biomédica más reciente la información relacionada con la vía de señalización Wnt-β- catenina y su participación en la génesis de padecimientos como la EA y el SXF. También se analiza el papel que podría desempeñar esta vía metabólica para explicar el riesgo disminuido que tienen estos pacientes de desarrollar cáncer.Conclusiones. Las múltiples evidencias encontradas sugieren que la vía Wnt-β-catenina podría estar regulando un conjunto de genes relacionados con el control del ciclo celular y la apoptosis, logrando un estado metabólico en el que, en padecimientos como la EA y el SXF, las células tendrían mayor susceptibilidad a entrar en apoptosis que a entrar en mitosis, lo que explicaría una disminución en el riesgo de desarrollar cáncer (AU)

Introduction. Various disorders affecting the canonical Wnt/β-catenin signalling pathway have been related to the activation or inactivation of oncogenes and tumour suppressor genes that give rise to a number of well-defined neoplasias, as well as several genes involved in a growing group of complaints, including Alzheimer’s disease (AD) and fragile X syndrome (FXS).Aim. To examine the Wnt/β-catenin signalling pathway as a possible common biological mechanism involved in the origin and development of neurodegenerative conditions and its relationship with cancer. Development. We review the most recent biomedical literature dealing with the Wnt/β-catenin signalling pathway and its participation in the genesis of complaints such as AD and FXS. An analysis is also conducted to determine the role that this metabolic pathway might play in explaining the lowered risk of developing cancer displayed by these patients. Conclusions. The evidence found suggests that the Wnt/β-catenin pathway could be regulating a set of genes linked with the control of the cell cycle and apoptosis. This would give rise to a metabolic state in which, in conditions such as AD and FXS, the cells would be more likely to undergo apoptosis than initiate mitosis, which would in turn account for the reduced risk of developing cancer (AU)

[WNT-ß-catenin signaling pathway and its relationship with cancer]. / La vía de señalización Wnt-ß-catenina y su relación con cáncer.

The Wnt-ß-catenin signalling pathway plays a crucial role in the regulation, differentiation, proliferation and cellular death processes; consequently, alterations in this pathway are involved in numerous abnormalities of development, growth and homeostasis in animal organisms. Wnt proteins include a numerous family of secretion glycoproteins which join to Frizzled receptors and Low Density Lipoprotein Receptor-related Protein, in order to stabilize the critical ß-catenin protein, and to initiate an intricate signaling cascade, which is related to multiple nucleocytoplasmatic processes. Alterations in the canonical Wnt-ß-catenin signaling pathway have been associated with variations in a number of proteins participating in this route, or with activation / inactivation of oncogenes and tumor suppressor genes, which explain different processes of tumorigenesis, in addition to a number of malformations and human diseases. This review describes the relations between the Wnt-ß-catenin signaling pathway with different neoplasic processes, as well as its application in the diagnosis and prognosis of cancer.

Gene expression profiling identifies WNT7A as a possible candidate gene for decreased cancer risk in fragile X syndrome patients.

BACKGROUND AND AIMS: Although sporadic cases of cancer in patients with fragile X syndrome (FXS) have been reported, extensive studies carried out in Denmark and Finland concluded that cancer incidence in these patients is lower than in the general population. On the other hand, the FMR1 protein, which is involved in the translation process, is absent in FXS patients. Hence, it is reasonable to assume that these patients exhibit an abnormal expression of some proteins involved in regulating tumor suppressor genes and/or oncogenes, thus explaining its decreased cancer frequency. We undertook this study to analyze the expression of oncogenes and tumor suppressor genes in fragile X syndrome patients. METHODS: Molecular analysis of the FMR1 gene was achieved in 10 male patients and controls. Total RNA from peripheral blood was used to evaluate expression of oncogenes and tumor suppressor genes included in a 10,000 gene microarray library. Quantitative real-time PCR was utilized to confirm genes with differential expression. RESULTS: Among 27 genes showing increased expression in FXS patients, only eight genes exhibited upregulation in at least 50% of them. Among these, ARMCX2 and PPP2R5C genes are tumor suppressor related. Likewise, 23/65 genes showed decreased expression in >50% of patients. Among them, WNT7A gene is a ligand of the beta-catenin pathway, which is widely related to oncogenic processes. Decreased expression of WNT7A was confirmed by quantitative RT-PCR. Expression of c-Myc, c-Jun, cyclin-D and PPARdelta genes, as target of the beta-catenin pathway, was moderately reduced in FXS patients. CONCLUSIONS: Results suggest that this diminished expression of the WNT7A gene may be related to a supposed protection of FXS patients to develop cancer.

[Molecular diagnosis in Huntington's disease]. / Diagnóstico molecular de la enfermedad de Huntington.

Huntington's disease (HD) is a neurological degenerative disorder, inherited by an autosomal dominant mode, and caused by a CAG triplet expansion coding for a poly-glutamine sequence in the huntingtin protein. HD affects 5-10 in 100,000 individuals from Caucasian population. Clinically patients display motor, cognitive and psychological impairment, and death within 10-15 years. Concrete advances have been achieved in the knowledge of the mutational mechanism, alteration of the protein product and their neuropathological effects. A number of tests such as PCR with or without DNA modification, Southern blot and mixed methods are analyzed. We describe their characteristics and effectiveness for the molecular diagnosis of HD.