ESR1 and hamartoma: It seems that hamartoma stromal cells expressed HMGA2, ER, and PR in 79%, 66%, and 76.3% of cases, respectively, compared to 7.7%, 23%, and 19% in normal breast tissue, respectively (p  <  0.0001; p  =  0.0005; p  <  0.0001) [21,22].