This is currently a correlation; however, two sets of genetic data strongly support the evidence of a causal relationship: the frequency of the C allele at the SNP rs8570 position in the 3’UTR of RRAS2 in breast tumors, and the overexpression of the RRAS2 gene in a non-tumoral tissue (blood) of breast cancer patients. The gene discussed is RRAS2; the disease is breast neoplasm.