ADRA1A and breast cancer: Regarding the catecholamine biosynthesis, Pearson’s analysis revealed that (i) ADRA2A and ADRB2 were negatively related, while ADRA1B and ADRA2C were positively correlated with the levels of TH; (ii) ADRA1A, ADRA2A, ADRA2B, ADRB1, ADRB2, ADRB3 were positively correlated with the levels of DBH; and interestingly, (iii) the three mostly expressed ADRs in BC tissue, ADRA2A, ADRA2C, and ADRB2, were positively related with PNMT (an enzyme responsible for the synthesis of EPI).