Whole sequencing of the mitochondrial genome of breast cancer tissue in Mexican-mestizo postmenopausal women with different body mass index

Abstract Background Mitochondrial and oxidative stress has been related to obesity and breast cancer being this cancer more frequent and more aggressive in postmenopausal women with obesity. Objective The objective of this study was to investigate whether Mexican-Mestizo postmenopausal women with breast cancer and obesity present different somatic mutations in the mitochondrial DNA (mtDNA) when compared to women with normal body mass index (BMI). Subjects and Methods We included six Mexican-Mestizo postmenopausal women bearing breast cancer and who underwent mastectomy or breast-conserving surgery. BMI was determined in each case. Patients’ genomic DNA was isolated from blood leukocytes and tumor tissue samples. Whole mtDNA sequence was determined by MitoChip v2.0 mitochondrial resequencing array, and data were analyzed using the GeneChip Sequence Analysis Software. Tumor mtDNA sequence was compared with matched leukocyte mtDNA sequence. Results Three women had a normal BMI and three presented obesity. Overall, we found 64 genetic variants: 53.1% were somatic mutations and 46.9% were polymorphisms; 44.1% were in the non-coding region and 55.9% were in genes that encode for mitochondrial proteins. Among the somatic mutations, 67.7% were in patients with normal BMI and 32.3% in patients with obesity. Conclusions We did not find a higher frequency of mitochondrial somatic mutations in postmenopausal women with breast cancer and obesity compared to those with normal BMI. However, results could be due to the small number of women studied.

Avances en distrofias musculares / Advances in muscular dystrophies

Las distrofias musculares son un grupo de enfermedades heredadas que se pueden iniciar en etapas que van desde el nacimiento hasta la edad adulta. Existen varios tipos pero en todos se observa debilidad y pérdida progresiva del músculo que conllevan a pérdida de la fuerza muscular, discapacidad gradual y algunas veces ocasionan deformidades. Estas enfermedades se pueden clasificar de acuerdo con los músculos involucrados, modelo de herencia y edad de inicio. Sin embargo, la identificación reciente de varios genes y proteínas responsables de estas patologías ha incrementado la heterogeneidad genética y clínica, modificando criterios de clasificación e incorporando conocimientos nuevos en la fisiopatología de dichas enfermedades. Así mismo, con el uso de métodos de genética molecular y bioquímicos es factible realizar el diagnóstico preciso de estos padecimientos y hacer una correlación entre la clínica y los defectos genéticos.

Analysis of dystrophin gene deletions in patients from the Mexican population with Duchenne/Becker muscular dystrophy

Forty unrelated Mexican patients with Duchenne/Backer muscular dystrophy were analyzed for intragenic DMD gene deletions, using the multiplex amplification of 15 deletion-prone oxons described by Chamberlain et al. and beggs et al. The percentage of deletions was 52.5 percent, and the majority of them (86.3 percent) were located at the hot spot deletion region which encompasses exons 44 - 55. This frequency is higher than that found in American and European populations. There were no correlations between deletion size, location and clinical severity