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Hereditary breast and ovarian cancer (HBOC) syndrome is a genetic condition that increases the risk of breast cancer by 80% and that of ovarian cancer by 40%. The most common pathogenic variants (PVs) causing HBOC occur in the BRCA1 gene, with more than 3850 reported mutations in the gene sequence. The prevalence of specific PVs in BRCA1 has increased across populations due to the effect of founder mutations. Therefore, when a founder mutation is identified, it becomes key to improving cancer risk characterization and effective screening protocols. The only founder mutation described in the Mexican population is the deletion of exons 9 to 12 of BRCA1 (BRCA1Δ9-12), and its description focuses on the gene sequence, but no transcription profiles have been generated for individuals who carry this gene. In this study, we describe the transcription profiles of cancer patients and healthy individuals who were heterozygous for PV BRCA1Δ9-12 by analyzing the differential expression of both alleles compared with the homozygous BRCA1 control group using RT-qPCR, and we describe the isoforms produced by the BRCA1 wild-type and BRCA1Δ9-12 alleles using nanopore long-sequencing. Using the Kruskal-Wallis test, our results showed a similar transcript expression of the wild-type allele between the healthy heterozygous group and the homozygous BRCA1 control group. An association between the recurrence and increased expression of both alleles in HBOC patients was also observed. An analysis of the sequences indicated four wild-type isoforms with diagnostic potential for discerning individuals who carry the PV BRCA1Δ9-12 and identifying which of them has developed cancer.
Assuntos
Alelos , Proteína BRCA1 , Síndrome Hereditária de Câncer de Mama e Ovário , Humanos , Proteína BRCA1/genética , Feminino , Síndrome Hereditária de Câncer de Mama e Ovário/genética , Pessoa de Meia-Idade , Predisposição Genética para Doença , Adulto , Efeito Fundador , Éxons/genética , Neoplasias da Mama/genética , Heterozigoto , Mutação , México , Neoplasias Ovarianas/genética , Relevância ClínicaRESUMO
PURPOSE: Astrocytomas are a type of malignant brain tumor with an unfavorable clinical course. The impact of AGT and MGMT somatic variants in the prognosis of astrocytoma is unknown, and it is controversial for TP53. Moreover, there is a lack of knowledge regarding the molecular characteristics of astrocytomas in Mexican patients. METHODS: We studied 48 Mexican patients, men and women, with astrocytoma (discovery cohort). We performed DNA deep sequencing in tumor samples, targeting AGT, MGMT and TP53, and we studied MGMT gene promoter methylation status. Then we compared our findings to a cohort which included data from patients with astrocytoma from The Cancer Genome Atlas (validation cohort). RESULTS: In the discovery cohort, we found a higher number of somatic variants in AGT and MGMT than in the validation cohort (10.4% vs < 1%, p < 0.001), and, in both cohorts, we observed only women carried variants AGT variants. We also found that the presence of either MGMT variant or promoter methylation was associated to better survival and response to chemotherapy, and, in conjunction with TP53 variants, to progression-free survival. CONCLUSIONS: The occurrence of AGT variants only in women expands our knowledge about the molecular differences in astrocytoma between men and women. The increased prevalence of AGT and MGMT variants in the discovery cohort also points towards possible distinctions in the molecular landscape of astrocytoma among populations. Our findings warrant further study.
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Astrocitoma , Neoplasias Encefálicas , Feminino , Humanos , Masculino , Astrocitoma/patologia , Biomarcadores , Neoplasias Encefálicas/patologia , DNA/uso terapêutico , Metilação de DNA , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Mutação , Prognóstico , Análise de Sequência de DNA , Proteína Supressora de Tumor p53/genética , Proteínas Supressoras de Tumor/genéticaRESUMO
Purpose: Neurofibromatosis type 1 (NF1) is a complex, multisystem disorder that is characterized, among other features, by a higher risk of developing benign and malignant tumors. Despite NF1 being one of the most common autosomal dominant genetic disorders, data from adult individuals in several world regions remain elusive, including Hispanics. Methods: The present is a retrospective cohort study conducted among adult patients with a confirmed diagnosis of NF1 who attended a single cancer-reference center, the Instituto Nacional de Cancerología in Mexico City from 2001 to 2021. Data were extracted from electronic health records and collected in an anonymous database by an NF1-expert physician in order to obtain demographic characteristics and detailed information regarding the development of tumors among this patient subgroup. All patients with malignant tumors or with benign tumors, which severely affected their quality of life, were included in this study. Results: Patient records were reviewed from 2001 to 2021. A total of N = 29 patients met the criteria, with a higher proportion of female compared with male subjects [N = 22 (75.9%) vs. N = 7 (24.1%)]. Patients had a mean age at diagnosis of tumors of 32.2 years (SD = 11.2 years). In terms of malignant neoplasms, the most frequent malignant tumor presented by patients in this cohort was malignant peripheral nerve sheath tumors (N = 7, 24.1%), this was followed by breast cancer (n = 4, 13.8% among all patients, 18.2% among female patients). Other tumors also identified in this cohort included melanoma, gastrointestinal stromal tumors, and rectal cancer. Conclusion: In Mexico, patients diagnosed with NF1 develop diverse tumors as adults. As described in other studies, the most frequent malignant tumor in this patient population is the malignant peripheral nerve sheath tumor. Further studies are required to increase the scarce information available for adult Hispanics with NF1.
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Lynch syndrome (LS) is the main hereditary colorectal cancer syndrome. There have been few reports regarding the clinical and molecular characteristics of LS patients in Latin America; this is particularly true in the Mexican population, where no information is available. The present study aims to describe the clinical and molecular spectrum of variants in a cohort of patients diagnosed with LS in Mexico. We present a retrospective analysis of 412 patients with suspected LS, whose main site of cancer diagnosis was the colon (58.25%), followed by the endometrium (18.93%). Next-generation sequencing analysis, with an extensive multigene panel, showed that 27.1% (112/414) had a variant in one of the genes of the mismatch repair pathway (MMR); 30.4% (126/414) had a variant in non-MMR genes such as CHEK2, APC, MUTYH, BRCA1, and BRCA2; and 42.5% (176/414) had no genetic variants. Most of the variants were found in MLH1. Pathogenic variants (PVs) in MMR genes were identified in 65.7% (96/146) of the total PVs, and 34.24% (45/146) were in non-MMR genes. Molecular and clinical characterization of patients with LS in specific populations allowed personalized follow-up, with the option for targeted treatment with immune checkpoint inhibitors and the development of public health policies. Moreover, such characterization allows for family cascade testing and consequent prevention strategies.
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Neoplasias Colorretais Hereditárias sem Polipose , Neoplasias Colorretais Hereditárias sem Polipose/diagnóstico , Neoplasias Colorretais Hereditárias sem Polipose/epidemiologia , Neoplasias Colorretais Hereditárias sem Polipose/genética , Reparo de Erro de Pareamento de DNA/genética , Proteínas de Ligação a DNA/genética , Feminino , Mutação em Linhagem Germinativa , Humanos , Inibidores de Checkpoint Imunológico , México/epidemiologia , Proteína 2 Homóloga a MutS/genética , Estudos RetrospectivosRESUMO
Abstract Background: Patients with familial erythrocytosis type 2 have no increased risk of von Hippel-Lindau-associated tumors, although mutations in the VHL gene cause both pathologies. Case report: We present a case of a compound heterozygote patient with von Hippel-Lindau disease and familial erythrocytosis type 2. One of the mutations found in our patient, c.416C>G (p.Ser139Cys) of the VHL gene, has not been previously reported. This case is the second one reported where von Hippel-Lindau disease and familial erythrocytosis type 2 coexist in the same individual. Conclusions: Despite the low frequency of familial erythrocytosis type 2 in patients with von Hippel-Lindau disease, the possibility of this diagnosis should be considered to avoid unnecessary invasive studies to explain the polyglobulia in these patients and guarantee an adequate follow-up and vigilance of both diseases.
Resumen Introducción: Los pacientes con eritrocitosis familiar tipo 2 no muestran un riesgo incrementado de desarrollar tumores asociados con la enfermedad de von Hippel-Lindau, a pesar de que ambas afecciones están causadas por variantes patogénicas en el gen VHL. Caso clínico: Se presenta el caso de un paciente heterocigoto compuesto con enfermedad de von Hippel-Lindau y eritrocitosis familiar tipo 2. Una de las variantes patogénicas en el paciente, VHL c.416C>G (p.Ser139Cys), no ha sido previamente reportada. Este es el segundo reporte de caso en que la enfermedad de von Hippel-Lindau y la eritrocitosis familiar tipo 2 coexisten en el mismo individuo. Conclusiones: A pesar de la baja frecuencia de la eritrocitosis familiar tipo 2 en pacientes con enfermedad de von Hippel-Lindau, la posibilidad del diagnóstico debe considerarse con el fin de evitar estudios invasivos innecesarios para explicar la presencia de poliglobulia en estos pacientes y para garantizar un adecuado seguimiento y una correcta vigilancia de ambas enfermedades.
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BACKGROUND: Patients with familial erythrocytosis type 2 have no increased risk of von Hippel-Lindau-associated tumors, although mutations in the VHL gene cause both pathologies. CASE REPORT: We present a case of a compound heterozygote patient with von Hippel-Lindau disease and familial erythrocytosis type 2. One of the mutations found in our patient, c.416C>G (p.Ser139Cys) of the VHL gene, has not been previously reported. This case is the second one reported where von Hippel-Lindau disease and familial erythrocytosis type 2 coexist in the same individual. CONCLUSIONS: Despite the low frequency of familial erythrocytosis type 2 in patients with von Hippel-Lindau disease, the possibility of this diagnosis should be considered to avoid unnecessary invasive studies to explain the polyglobulia in these patients and guarantee an adequate follow-up and vigilance of both diseases.
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Policitemia , Doença de von Hippel-Lindau , Criança , Humanos , Mutação , Policitemia/congênito , Policitemia/diagnóstico , Policitemia/genética , Proteína Supressora de Tumor Von Hippel-Lindau/genética , Doença de von Hippel-Lindau/diagnóstico , Doença de von Hippel-Lindau/genéticaRESUMO
Astrocytoma is the most common type of primary brain tumor. The risk factors for astrocytoma are poorly understood; however, germline genetic variants account for 25% of the risk of developing gliomas. In this study, we assessed the risk of astrocytoma associated with variants in AGT, known by its role in angiogenesis, TP53, a well-known tumor suppressor and the DNA repair gene MGMT in a Mexican population. A case-control study was performed in 49 adult Mexican patients with grade II-IV astrocytoma. Sequencing of exons and untranslated regions of AGT, MGMT, and TP53 from was carried in an Ion Torrent platform. Individuals with Mexican Ancestry from the 1000 Genomes Project were used as controls. Variants found in our cohort were then assessed in a The Cancer Genome Atlas astrocytoma pan-ethnic validation cohort. Variants rs1926723 located in AGT (OR 2.74, 1.40-5.36 95% CI), rs7896488 in MGMT (OR 3.43, 1.17-10.10 95% CI), and rs4968187 in TP53 (OR 2.48, 1.26-4.88 95% CI) were significantly associated with the risk of astrocytoma after multiple-testing correction. This is the first study where the AGT rs1926723 variant, TP53 rs4968187, and MGMT rs7896488 were found to be associated with the risk of developing an astrocytoma.
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Angiotensinogênio/genética , Astrocitoma/genética , Neoplasias Encefálicas/genética , Metilases de Modificação do DNA/genética , Enzimas Reparadoras do DNA/genética , Variação Genética/genética , Proteína Supressora de Tumor p53/genética , Proteínas Supressoras de Tumor/genética , Adulto , Astrocitoma/epidemiologia , Astrocitoma/patologia , Neoplasias Encefálicas/epidemiologia , Neoplasias Encefálicas/patologia , Estudos de Casos e Controles , Estudos de Coortes , Feminino , Regulação Neoplásica da Expressão Gênica/genética , Humanos , Masculino , México/epidemiologia , Pessoa de Meia-IdadeRESUMO
The deletion of exons 9 to 12 of BRCA1 (9-12 del BRCA1) is considered a founder mutation in the Mexican population. We evaluate the usefulness of the target detection of 9-12 del BRCA1 as the first molecular diagnostic strategy in patients with Hereditary Breast and Ovarian Cancer (HBOC). We performed the genetic assessment of 637 patients with suspected HBOC. The region corresponding to the breakpoints for the 9-12 del BRCA1 was amplified by polymerase chain reaction (PCR). An analysis of the clinical data of the carriers and non-carriers was done, searching for characteristics that correlated with the deletion. The 9-12 del BRCA1 was detected in 5% of patients with suspected HBOC (30/637). In patients diagnosed with ovarian cancer, 13 of 30 were 9-12 del BRCA1 carriers, which represents 43%. We found a significant association between the 9-12 del BRCA1 carriers with triple negative breast cancer and high-grade papillary serous ovarian cancer. We concluded that the detection of the 9-12 del BRCA1 is useful as a first molecular diagnostic strategy in the Mexican population. In particular, it shortens the gap in genetic assessment in patients with triple negative breast cancer and ovarian cancer.
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Proteína BRCA1/genética , Neoplasias da Mama/genética , Predisposição Genética para Doença/genética , Mutação em Linhagem Germinativa , Neoplasias Ovarianas/genética , Adulto , Neoplasias da Mama/diagnóstico , Éxons/genética , Saúde da Família , Feminino , Efeito Fundador , Testes Genéticos , Humanos , México , Pessoa de Meia-Idade , Neoplasias Ovarianas/diagnóstico , Deleção de Sequência , Adulto JovemRESUMO
Inherited mutations in the RET proto-oncogene, which encodes a receptor tyrosine kinase, predispose individuals to the multiple endocrine neoplasia type 2 (MEN 2) cancer syndromes. The major component tumor of these syndromes is medullary thyroid carcinoma (MTC). To date, somatic mutations in RET have been identified in tumors from individuals with MEN 2 finding. RET M918T mutation is present in 95% of the MEN2B cases, and approximately 50% of sporadic MTCs harbor this mutation. We performed a mutational analysis in 17 cases of Medullary thyroid carcinoma, the somatic missense mutation at codon 918 of RET was found in 2 of the 17 MTCs, and one case presented MEN2 phenotype including MTC. The percentage of RET M918T mutation is similar in Mexican MTC patients to other series, although other mutations could be implicated in our population.
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Carcinoma Neuroendócrino/genética , Mutação de Sentido Incorreto , Proteínas Proto-Oncogênicas c-ret/genética , Neoplasias da Glândula Tireoide/genética , Adolescente , Adulto , Substituição de Aminoácidos , Carcinoma Neuroendócrino/epidemiologia , Análise Mutacional de DNA , Feminino , Frequência do Gene , Humanos , Masculino , Metionina/genética , México/epidemiologia , Pessoa de Meia-Idade , Proto-Oncogene Mas , Treonina/genética , Neoplasias da Glândula Tireoide/epidemiologia , Adulto JovemRESUMO
BACKGROUND: Hyper-CVAD is the treatment for patients with acute lymphoblastic leukemia in our institution. OBJECTIVE: To evaluate the impact of single nucleotide polymorphisms at genes associated with methotrexate metabolism on survival. METHODS: The presence of the single nucleotide polymorphisms G80A at reduced folate carrier-1 gene and C677T in the methylenetetrahydrofolate reductase gene was determined by denaturing high performance liquid chromatography and validated by sequencing. Both single nucleotide polymorphisms were evaluated in 71 healthy donors and in an exploratory pilot trial with acute lymphoblastic leukemia patients to determine the influence of these single nucleotide polymorphisms on clinical outcome. Clinical characteristics, response, and outcome were registered. A Cox regression analysis was done to evaluate factors influencing response and overall survival. RESULTS: There were no differences in the frequency of single nucleotide polymorphisms between volunteers and acute lymphoblastic leukemia patients according to the Hardy-Weinberg test. Sensitivity and specificity were 72 and 91% for the G80A, and 64 and 75% for the C677T, respectively. The multivariate analysis showed that the T-immunophenotype and the presence of single nucleotide polymorphism G80A reduced folate carrier-1 were associated with a shorter relapse-free survival and overall survival. CONCLUSIONS: The presence of G80A single nucleotide polymorphism at reduced folate carrier-1 gene in acute lymphoblastic leukemia patients was associated with a poorer prognosis.