Neutrophils physically interact with cancer cells in breast cancer

We performed RNA-sequencing of single cells and physically interacting cells (PIC-seq) along murine mammary gland development and carcinogenesis. We uncovered that neutrophils appear transiently during early development, re-emerge in physical interactions with tumor cells from neoplasia and are further expanded in advanced carcinoma. Investigation of neutrophil heterogeneity revealed seven transcriptional states linked to age and cancer stage. We also identified a molecular program upregulated by the physical interaction between neutrophils and tumor cells, promoting angiogenesis, invasion and metastasis.