Este trabajo fue posible debido al apoyo del Consejo Na-cional de Ciencia y Tecnología (CONCYTEC), contrato 359-2006-CONCYTEC-OAJ y de la Facultad de Medicina de U. de San Martín de Porres (proyectos E10012007006, E10012009013).

Universidad de San Martin de Porres Funds, Lima, Per (Project number E20012003005), Consejo Nacional de Ciencia y Tecnolog a Per (CONCYTEC).

We analyzed mitochondrial DNA haplotypes from 144 samples of islanders of the Taquile and Amantani (Quechua speakers) and Los Uros and Anapia (Aymara speakers) of the Lake Titicaca, Peru. We have found the highest frequency of B1 mtDNA haplotype ever reported: 100% in Taquile (n= 57); 88,6% in Amantani (n= 35); 87,5% in Anapia (n= 24) and 75% in Los Uros (n= 28). There are other haplotypes but in low frequencies: 11,4% of C1 in Amantani; 17,9% of A2 and 7,1% of D1 in Los Uros; 4,2% of C1, C2 and D1 haplotypes in Anapia. The high frequency of the B1 haplotype indicates that Taquile, Amantaní and Anapia islands have been populated by a reduced founder group. Although the genetic affinity between islanders of Anapia and Los Uros, the proportion of some alleles in the latter suggest the persistence of the uru genetic background.

Background: Cell-free DNA (cfDNA) is used in clinical research to identify biomarkers for diagnosis of and follow-up on cancer. Here, we propose a fast and innovative approach using traditional housekeeping genes as cfDNA targets in a copy number analysis. We focus on the application of highly sensitive technology such as digital PCR (dPCR) to differentiate breast cancer (BC) patients and controls by quantifying regions of PUM1 and RPPH1 (RNase P) in plasma samples. Methods: We conducted a case-control study with 82 BC patients and 82 healthy women. cfDNA was isolated from plasma using magnetic beads and quantified by spectrophotometry to estimate total cfDNA. Then, both PUM1 and RPPH1 genes were specifically quantified by dPCR. Data analysis was calibrated using a reference genomic DNA in different concentrations.Results: We found RNase P and PUM1 values were correlated in the patient g...

OAJ-2003

Background: PIK3CA is a gene frequently mutated in breast cancer. With the FDA approval of alpelisib, the evaluation of PIK3CA for activating mutations is becoming routinely. Novel platforms for gene analysis as digital PCR (dPCR) are emerging as a potential replacement for the traditional Sanger sequencing. However, there are still few studies on chip-based dPCR to detect mutations in tumor samples. Thus, this cross-sectional study aimed to assess the sensibility of a chip-based dPCR to detect and quantify PIK3CA mutations and compare its performance with Sanger sequencing. Materials and Methods: Tumor samples from 57 breast cancer patients (22 pre-treatment samples, 32 tumors after neoadjuvant chemotherapy, and three lymph nodes) were collected and analyzed by Sanger sequencing and dPCR for the three PIK3CA most relevant mutations (p.E545K, p. H1047R, and p. H1047L). Digital PCR sensit...

Background: Promoter hypermethylation is one of the enabling mechanisms of hallmarks of cancer. Tumor suppressor genes like RARB and GSTP1 have been reported as hypermethylated in breast cancer tumors compared with normal tissues in several populations. This case–control study aimed to determine the association between the promoter methylation ratio (PMR) of RARB and GSTP1 genes (separately and as a group) with breast cancer and its clinical-pathological variables in Peruvian patients, using a liquid biopsy approach. Methods: A total of 58 breast cancer patients and 58 healthy controls, matched by age, participated in the study. We exacted cell-free DNA (cfDNA) from blood plasma and converted it by bisulfite salts. Methylight PCR was performed to obtain the PMR value of the studied genes. We determined the association between PMR and breast cancer, in addition to other clinicopathologi...