It should also be noted that their 3D morphology makes it possible to distinguish non-tumor from cancer cells: the former typically form acinar structures, have a rounded shape with established polarity and lumen, and exhibit high expression of Keratin 15 (KRT15), Fatty acid-binding protein 5 (FABP5), and Anterior gradient protein 2 homolog (AGR2) [22,27]. This evidence concerns the gene KRT15 and cancer.