Figure 4b presents the correlation between type of prior treatment received and the incidence of new AA for patients with HR+/HER2- BC; prior use of AI, SERD or PI3K inhibitor was significantly correlated with the incidence of AA in the BL draw (68% vs. 45% of patients who received vs. did not receive prior AI, respectively; p < 0.0001, 74% vs. 56% of patients who received vs. did not receive prior SERD, respectively; p = 0.001, and 94% vs. 60% of patients who received vs. did not receive prior PI3K inhibitor, respectively; p = 0.002). Here, PIK3CA is linked to breast cancer.