As GIST derive from either ICC or mesenchymal precursors which give rise to smooth muscle cells or ICC [5], we also compared the expression level of the myoid differentiation markers LIX1, a transcription factor expressed in mesenchymal progenitors [21], and (alpha) α-smooth muscle actin (αSMA), a smooth muscle cell marker. The gene discussed is ACTA1; the disease is intrahepatic cholangiocarcinoma.