In contrast, the majority of LumB (78%) tumours shifted to LumA, mirroring the high transition rate seen in patients with ER+/HER2−breast cancer in the POETIC & NeoAI cohort (>1-month neoadjuvant NT),26 indicating similar AI responsiveness regarding these ISs irrespective of HER2 status. Here, ERBB2 is linked to neoplasm.