ACTA1 and breast carcinoma: Although the study by Becker et al. implicated α-SMA-positive CAFs in breast cancer as tumor-promoting, Özdemir et al. reported that depletion of α-SMA-positive CAFs led cells in the non-invasive precursor stage or PDAC stage to become invasive, undifferentiated tumors with enhanced hypoxia, show an epithelial-to-mesenchymal transition and transform into cancer stem cells, thus adversely affecting animal survival 102.