The vast majority (up to 88%) of neuropilin-1+ cells proximal to the panobinostat well were cytotoxic neutrophils (Fig. 5a and Extended Data Fig. 6d), suggesting neuropilin-1 as a novel biomarker of anti-tumor neutrophils in breast cancer—a hypothesis that remains to be functionally tested. Here, NRP1 is linked to breast carcinoma.