Overall, this strong correlation between FLP formation and outgrowth competency of BCC is consistent with a previous report.7 Collectively, these results suggest that Pfn1 depletion induces outgrowth defect in TNBC cells by affecting an ECM-stiffness sensitive signalling pathway that is important for BCC outgrowth, which is likely to be independent of the FAK/ERK signalling axis. Here, PTK2 is linked to skin basal cell carcinoma.