Understanding the cancer/tumor biology from 2D to 3D

Cancer is now the second leading cause of mortality worldwide. It predicts that there are 595,690 cancer deaths and approximately 1.7 million new cases diagnosed in 2016 in the United States (1). Therefore, great efforts have been made in the cancer treatment. First of all, the cancer biology needs full understanding. Experiments with cell monolayer have allowed the interpretation of complicated biological phenomena (i.e., molecular biology, stem cell differentiation, and tissue morphogenesis) and are the most popular protocol. However, as early as 1972, the differences between cells cultured and grown on a flat surface and three-dimensional formats were explored (2).