Protein expression levels were measured after stimulating neutrophils through using conditioned media (CM) from a variety of subtypes of breast cancer cells, which revealed high expression of c-FOS in neutrophils stimulated with CM from TNBC subtype cell lines HCC1937 and MDA-MB-231, with a positive correlation with PAD4 expression (Fig. 4A). This evidence concerns the gene PADI4 and breast cancer.