[Genetic variants in miRNAs and its association with breast cancer]

In Mexico, breast cancer represents the first cause of cancer death in females. At the molecular level, non-coding RNAs and especially microRNAs have played an important role in the origin and development of this neoplasm In the Anglo-Saxon population, diverse genetic variants in microRNA genes and in their targets are associated with the development of this disease. In the Mexican population it is not known if these or other variants exist. Identification of these or new variants in our population is fundamental in order to have a better understanding of cancer development and to help establish a better diagnostic strategy.

DNA was isolated from mammary tumors, adjacent tissue and peripheral blood of Mexican females with or without cancer. From DNA, five microRNA genes and three of their targets were amplified and sequenced. Genetic variants associated with breast cancer in an Anglo- Saxon population have been previously identified in these sequences.

In the samples studied we identified seven single nucleotide polymorphisms (SNPs). Two had not been previously described and were identified only in women with cancer.

The new variants may be genetic predisposition factors for the development of breast cancer in our population. Further experiments are needed to determine the involvement of these variants in the development, establishment and progression of breast cancer.