ACTA1 and malignant mesothelioma: Additionally, to know the potential identity of CD90+ mesenchymal cells, we evaluated the co-expression of CD90/αSMA and CD90/FAP, two classical CAF markers, on sequential sections of three patients (epithelioid, sarcomatoid and biphasic malignant mesothelioma) including pre-neoadjuvant chemotherapy (NAC) as well as post-NAC samples.