ACTA1 and cancer: Four common subtypes (67% of cases in the studied series) with significant differences in the areas of cancer cell proliferation (Ki67) and migration (collagen fiber alignment, metalloproteinases—MMP14), cancer stem cells (CD44, CD133, ALDH1), extracellular matrix (total collagen, collagen I and III, fibronectin, hyaluronan), cancer-associated fibroblasts (αSMA), and cancer–stroma interactions (integrins α2, α5, α1; caveolin-1) were distinguished.