The patient (III:7) (Figure 1) was first diagnosed with an invasive ductal carcinoma of the right mammary gland at the age of 35 (pT1c (2), N1, G3, estrogen receptor (ER) positive, progesterone receptor (PR) negative, and human epidermal growth factor receptor 2 (HER2) negative). Here, ESR1 is linked to invasive ductal breast carcinoma.