We have screened 987 samples from unselected breast cancer patients for the four most common BRCA1 mutations in Greece: c.5266dupC (5382insC), G1738R (c.5212G>A), the 3.2 kb deletion of exon 20 (c.5256_5277+3179del3200), and the 4.4 kb deletion of exon 24 (c.5468-285_5592+4019del4429_insCACAG). Here, BRCA1 is linked to breast cancer.