ESR1 and breast cancer: CCRCC component showed CD10 (+), Vimentin (+), CAIX (+), PAX-8 (+), p504S (-), CD117 (-), and 3% Ki-67 proliferation index while metastatic BC component exhibited ER (50%+++), GATA3 (+), PR (-), HER-2 (1+), p120 (cell membrane +), and 20% Ki-67 proliferation index.