ATF5 and cancer: Furthermore, ATF5 initiates expression of its pro-invasion down-stream targets, the collagen receptor integrin α2β1 genes ITGα2 and ITGβ1, which can bind to collagen type I, E-cadherin, and matrix metalloproteinase to induce tumor invasion in several human cancer cell lines, such as lung, breast, cervical, gastric, fibrosarcoma, and pancreatic cancers [59,60].