ACTA2 and neoplasm: To investigate further how these differing behaviours in non-adherent culture might impact on tumour growth in vivo, primary tumours in BALB/c mice (Fig. 1B; Fig. S1A) and NSG mice (Fig. 1C) were sectioned and stained for αSMA (Acta2), a marker of activated fibroblasts, and endomucin, a marker of endothelial cells.