Effects of exogenous SDF-1α in the growth and generation of monolayer cocultures.SDF-1 knockdown BCCs (SDF-1 negative) were established as cocultures in the presence or absence of 0.1 ng/mL SDF-1α. (A) Cocultures with SDF-1–negative BCCs (left panel) without SDF-1α or with 0.1 ng/mL SDF-1α (right panel). Images were visualized, acquired, and processed as in Figure 3Ci-ii. (B) BCC counts in cocultures at 80% confluence (9 experiments with 3 different cell lines). *P < .05 versus cocultures with SDF-1 knockdown BCCs. Error bars indicate mean ± SD; n = 9.