Altogether, the Icelandic findings implicate epigenetic silencing of the BRCA1 gene in sporadic breast tumors. They even suggest that "the BRCA1 gene is implicated in sporadic breast tumorigenesis through epigenetic silencing and deletion of the BRCA1 gene," and that BRCA1 methylation is also found to be important in hereditary breast cancer, indicating similarities between BRCA1 methylated and hereditary BRCA1 breast tumors (Birgisdotter, et al. 9). While heredity factors strongly contribute to 5 to 10% of all breast cancer cases overall, it is questionable whether they have the same degree of risk as mutations in BRCA1 and BRCA1. The three studies examined in this research all strongly point to BRCA1 mutation as being responsible for high percentages of sporadic cancer, and possibly having an effect...

One would think that further studies need to be done to examine the exact effects and possible prevention of the BRCA1 mutation.
Birgisdottir, Valgerdur; Stefansson, Olafur a.; Bodvarsdottir, Sigridur K.; Hilmarsdottir, Holmfridur; Jonasson Jon G. And Eyfjord, Jorunn E.; "Epigenetic silencing and deletion of the BRCA1 gene in sporadic breast cancer." Breast Cancer Research 2006.

Han S-H, Lee K-R, Lee D-G, Kim B-Y, Lee K-E, ChungW-S. "Mutation analysis of BRCA1 and BRCA2 from 793 Korean patients with sporadic breast cancer." Clin Genet 2006: 70: BlackwellMunksgaard, 2006.

A van der Groep, P.; Bouter, a.; van der Zanden, R.; Siccama, I.; Menko, F.H.; Gille, J.J.P.; van Kalken, C.; van der Wall, E.; Verheijen, R.H.M.and van Diest, P.J.…