Breast Cancer Tissue Explants: An Approach to Develop Personalized Therapy in Public Health Services.

Breast cancer is one of the main causes of death worldwide. Lately, there is great interest in developing methods that assess individual sensitivity and/or resistance of tumors to antineoplastics to provide personalized therapy for patients. In this study we used organotypic culture of human breast tumor slices to predict the experimental effect of antineoplastics on the viability of tumoral tissue. Samples of breast tumor were taken from 27 patients with clinically advanced breast cancer; slices were obtained and incubated separately for 48 h with paclitaxel, docetaxel, epirubicin, 5-fluorouracil, cyclophosphamide, and cell culture media (control). We determined an experimental tumor sensitivity/resistance (S/R) profile by evaluating tissue viability using the Alamar Blue® metabolic test, and by structural viability (histopathological analyses, necrosis, and inflammation). These parameters were related to immunohistochemical expression of the estrogen receptor, progesterone receptor, and human epidermal growth factor receptor 2. The predominant histological type found was infiltrating ductal carcinoma (85.2%), followed by lobular carcinoma (7.4%) and mixed carcinoma (7.4%). Experimental drug resistance was related to positive hormone receptor status in 83% of samples treated with cyclophosphamide (p = 0.027). Results suggest that the tumor S/R profile can help to predict personalized therapy or optimize chemotherapeutic treatments in breast cancer.

Identification of Germline Variants in Patients with Hereditary Cancer Syndromes in Northeast Mexico.

Hereditary cancer syndromes (HCS) are genetic diseases with an increased risk of developing cancer. This research describes the implementation of a cancer prevention model, genetic counseling, and germline variants testing in an oncologic center in Mexico. A total of 315 patients received genetic counseling, genetic testing was offered, and 205 individuals were tested for HCS. In 6 years, 131 (63.90%) probands and 74 (36.09%) relatives were tested. Among the probands, we found that 85 (63.9%) had at least one germline variant. We identified founder mutations in BRCA1 and a novel variant in APC that led to the creation of an in-house detection process for the whole family. The most frequent syndrome was hereditary breast and ovarian cancer syndrome (HBOC) (41 cases with BRCA1 germline variants in most of the cases), followed by eight cases of hereditary non-polyposic cancer syndrome (HNPCC or Lynch syndrome) (with MLH1 as the primarily responsible gene), and other high cancer risk syndromes. Genetic counseling in HCS is still a global challenge. Multigene panels are an essential tool to detect the variants frequency. Our program has a high detection rate of probands with HCS and pathogenic variants (40%), compared with other reports that detect 10% in other populations.

ADIPOQ single nucleotide polymorphisms and breast cancer in northeastern Mexican women.

BACKGROUND: Adiponectin gene (ADIPOQ) polymorphisms have been shown to affect adiponectin serum concentration and some have been associated with breast cancer (BC) risk. The aims of this study were to describe the frequency of single nucleotide polymorphisms (SNPs) of ADIPOQ in Mexican women with BC and to determine if they show an association with it. METHODS: DNA samples from 397 patients and 355 controls were tested for the ADIPOQ gene SNPs: rs2241766 (GT) and rs1501299 (GT) by TaqMan allelic discrimination assay. Hardy-Weinberg equilibrium (HWE) was tested. Multiple SNP inheritance models adjusted by age and body mass index (BMI) were examined for the SNP rs1501299. RESULTS: We found that in the frequency analysis of rs1501299 without adjusting the BMI and age, the genotype distribution had a statistically significant difference (P = 0.003). The T allele was associated with a BC risk (OR, 1.99; 95% CI 1.13-3.51, TT vs. GG; OR, 1.53; 95% CI 1.12-2.09, GT vs. GG). The SNP rs2241766 was in HW disequilibrium in controls. In conclusion, the rs1501299 polymorphism is associated with a BC risk. CONCLUSIONS: Identification of the genotype of these polymorphisms in patients with BC can contribute to integrate the risk profile in both patients and their relatives as part of a comprehensive approach and increasingly more personalized medicine.

[C677T-SNP of methylenetetrahydrofolate reductase gene and breast cancer in Mexican women]. / SNP C677T del gen metilentetrahidrofolatoreductasa y cáncer de mama en mujeres mexicanas.

BACKGROUND: Low-penetrance susceptibility genes such as 5,10-methylenetetrahydrofolate reductase gene (MTHFR) have been considered in the progression of breast cancer (BC). Cancer is a result of genetic, environmental and epigenetic interactions; therefore, these genes should be studied in environmental context, because the results can vary between populations and even within the same country. The objective was to analyze the allelic and genotypic frequencies of the MTHFR C667T SNP in Mexican Mestizo patients with BC and controls from Northeastern Mexico. METHODS: 243 patients and 118 healthy women were studied. The analysis of the polymorphism was performed with a DNA microarray. Once the frequency of the polymorphism was obtained, Hardy-Weinberg equilibrium test was carried out for the genotypes. Chi square test was used to compare the distribution of frequencies. RESULTS: The allele frequency in patients was: C = 0.5406; T = 0.4594 and in controls C = 0.5678, T = 0.4322. Genotype in BC patients was: C / C = 29.9%, C / T = 48.3% and T / T = 21.8. The distribution in controls was: C / C = 31.4%, C / T = 50.8%, T / T = 17.8% (chi squared 0.77, p = 0.6801). CONCLUSIONS: Northeastern Mexican women in this study showed no association between MTFHR C667T SNP and the risk of BC. It seems that the contribution of this polymorphism to BC in Mexico varies depending on various factors, both genetic and environmental.

INTRODUCCIÓN: existen genes de susceptibilidad de baja penentrancia, como el gen de la 5,10-metilentetrahidrofolato reductasa (MTHFR), que participan en la progresión del cáncer de mama (CM). El cáncer es resultado de interacciones genéticas, ambientales y epigenéticas. Estos genes deben ser estudiados en el contexto del medio ambiente, ya que los resultados pueden variar de una población a otra, incluso dentro del mismo país. El objetivo fue analizar las frecuencias alélicas y genotípicas del polimorfismo C667T del gen de la MTHFR en pacientes mestizos mexicanos con CM y controles del noreste de México. MÉTODOS: se estudiaron 243 pacientes y 118 mujeres sanas. El análisis del polimorfismo se realizó con una microarreglo de ADN. Una vez que se obtuvo la fre cuencia del polimorfismo, la prueba de equilibrio de Hardy-Weinberg se llevó a cabo para los genotipos. Se utilizó chi cuadrada para comparar la distribución de frecuencias. RESULTADOS: la frecuencia de los alelos en los pacientes fue: C = 0.5406, T = 0.4594 y en los controles C = 0.5678, T = 0.4322. El genotipo en pacientes con CM fue: C / C = 29.9%, C / T = 48.3% y T / T = 21.8. La distribución en los controles fue: C / C = 31.4%, C / T = 50.8%, T / T = 17.8% (chi cuadrada 0.77, p = 0.6801). CONCLUSIONES: en este estudio no se observó relación entre el SNP MTFHR C667T y el riesgo de CM. Al parecer la contribución de este polimorfismo al CM en México varía dependiendo de varios factores tanto genéticos como ambientales.

Comparative study of polymorphism frequencies of the CYP2D6, CYP3A5, CYP2C8 and IL-10 genes in Mexican and Spanish women with breast cancer.

AIM: Pharmacogenetic studies in breast cancer (BC) may predict the efficacy of tamoxifen and the toxicity of paclitaxel and capecitabine. We determined the frequency of polymorphisms in the CYP2D6 gene associated with activation of tamoxifen, and those of the genes CYP2C8, CYP3A5 and DPYD associated with toxicity of paclitaxel and capecitabine. We also included a IL-10 gene polymorphism associated with advanced tumor stage at diagnosis. PATIENTS & METHODS: Genomic DNAs from 241 BC patients from northeast Mexico were genotyped using DNA microarray technology. RESULTS: For tamoxifen processing, CYP2D6 genotyping predicted that 90.8% of patients were normal metabolizers, 4.2% ultrarapid, 2.1% intermediate and 2.9% poor metabolizers. For paclitaxel and the CYP2C8 gene, 75.3% were normal, 23.4% intermediate and 1.3% poor metabolizers. Regarding the DPYD gene, only one patient was a poor metabolizer. For the IL-10 gene, 47.1% were poor metabolizers. CONCLUSION: These results contribute valuable information towards personalizing BC chemotherapy in Mexican women.