ADD3 and breast angiosarcoma: Though we failed to replicate the individual association of rs10509906 to disease, the intragenic epistatic effect between rs10509906 and rs2501577 was suggested as exhibiting susceptibility to BA, further cross-validated by multifactor dimensionality reduction (MDR) (P=0.068, OR = 1.37), which may explain extra hidden heritability of ADD3 to BA.