HIF1A and breast angiosarcoma: In this study, according to the qualitative evaluation, 35.7% of BA patients showed HIF-1α nuclear positivity in the cholangiocytes of portal tracts, portal–parenchymal interfaces, ductular reaction expanding outwards to parenchymal zone 1, fibrovascular septa, and subcapsular area, whereas HIF-1α positivity was absent in the biliary epithelium of all the controls (Figure 1A).