TNFRSF1A and breast angiosarcoma: The most significant changes in the levels of individual expression and co-expression of TNFR1 were observed in the patients with mild BA: the percentage of cells exclusively expressing TNFR1 was increased almost tenfold, from 2.84% in healthy volunteers to 27.6% in the patients with BA (p = 0.0014), while the percentage of double-positive cells was slightly reduced.