ADRB2 and angiosarcoma: To confirm this, we performed immunohistochemistry for the steady state protein levels of ADRB1, ADRB2, and ADRB3 on four clinically characterized human angiosarcoma tumors, revealing strong signals for ADRB1 and ADRB2 and weaker sample-dependent signals for ADRB3 (Figure 1A).