Strong membranous expression of pancytokeratins and E-cadherin in hybrid xenografts, comparable with the expression in parental lung cancer xenografts, and cell morphology were suggestive of the epithelial nature of the tumors, whereas enhanced expression of vimentin, α-SMA and fibronectin suggested an MSC contribution to the hybrid phenotype (Figure 8B). This evidence concerns the gene ACTA1 and lung cancer.