Accordingly, we analysed pSmad3 localization in the peritoneums of tumour‐bearing mice, where CAFs (α‐SMA‐positive) expressing nuclear pSmad3 were observed in the tumour stroma and, similarly to what was shown by our in vitro assays, pSmad3 remained cytoplasmic in OvCa cells (supplementary material, Figure S3). Here, ACTA1 is linked to neoplasm.