To better recapitulate the heterogeneity of the adenocarcinoma tumor lesion, we employed tumor spheroids formed by the combination of two different cell types; as a proof of concept, 3D spheroids obtained from a 1:1 mixture of murine fibroblasts and A549 cells (primed with TGFβ) were used. The gene discussed is TGFB1; the disease is neoplasm.