GPC1 and breast angiosarcoma: Recent genome-wide association studies (GWASs) identified common variants in ADD3, GPC1, and ARF6 associated with isolated BA (Garcia-Barceló et al., 2010; Leyva-Vega et al., 2010; Cheng et al., 2013; Cui et al., 2013; Ningappa et al., 2015).