Overabundance of circulating RNY transcripts and fragments has been associated with cancer. Here we analyzed the levels of RNYs in plasma collected from women before developing breast cancer and compared the results to matched controls that remained unaffected. Using small RNA-seq, two cohorts were analyzed: a cohort of women carriers of pathogenic variants in BRCA1 and BRCA2, and diagnosed with breast cancer as a first neoplasm within a period of < 12 months after blood test (n = 11), or that provided a blood sample at a similar age and remained unaffected (n = 13); and a cohort from a long-term prospective study, and comprising 8 sporadic breast cancer cases (diagnosed in a period of < 12 months after blood test) and 8 controls matched for individual and epidemiological variables Overall design: To investigate the basal levels of RNY transcripts and fragments in plasma of women that developed breast cancer and compare the results to women that remained cancer-free **RAW data will be uploaded to dbGAP**