This model features biculture spheroids (300–500 μm diameter) consisting of two human cell lines, vimentin-positive CCD-1137Sk fibroblasts forming the core and pan-cytokeratin (pan-CK)-positive HT-29 colon cancer cells that engulf them, as confirmed by multiplex-MALDI-immunohistochemistry (IHC)52 (Fig. 1b(i)). This evidence concerns the gene VIM and malignant colon neoplasm.