ESR1 and breast cancer: Results of immunohistochemical analysis showed that 12 patients had luminal A-type BC (ER/PR positivity and Her2 negativity; low score for Ki67), 32 patients had luminal B-type BC (ER/PR positivity and Her2 negativity or positivity; high score for Ki67), and 25 patients had TNBC (ER/PR and Her-2 negativity).