C3 and neoplasm: As expected, the unmixed, pure population of undifferentiated HL‐60 Bcl‐2 cells and differentiated neutrophils did not migrate at all toward FBS (Figure 8B; Figures S11A,B, Supporting Information, green and teal lines) since neutrophils can only sense chemoattractants such as leukotrienes (LTB4), chemokines (IL8), anaphylatoxins (C3a and C5a) as well as formyl peptides (fMLP).[46] The unmixed, pure population of MDA‐MB‐231TD cells migrated efficiently within 24 h (pink line), which was also expected since FBS is a known chemoattractant for these tumor cells.