Researchers in an UCSF-led team have developed a technique to create tiny models of human tissue called organoids by turning human cells into cellular LEGO bricks. This technique, named DNA Programmed Assembly of Cells (DPAC), allows researchers to study complex human tissues without using actual human subjects. To turn the cellular LEGOs into organoids, several sets of cells are laid down in layers, with each set designed to stick to particular partners. This method makes it possible to build complex tissue components, such as the mammary gland, and observe the effects of a single known mutated cell on the tissue. Researchers hope to use DPAC to study cancer and even grow completely functional human organs.