In two patients with LG-ESS with breast metastasis, the IHC results were as follows: vimentin (+ +), cyclin D1 (+), CD10 (+++), CK (+, locally scattered minority), PR (+/-, partially scattered minority), ER (-), Ki-67 (+, ~40%), H-Caldesmon (-), CD163 (-), CD34 (-), CK5/6 (-), Desmin (-), HMB45 (-), p63 (-), and STAT 6 (-). The gene discussed is ESR1; the disease is metastasis.