Similar Initiating Factors. Left side figure shows invasive bladder carcinoma (arrow) invading into normal tissue. These tumors are often induced by the overproduction of growth-promoting hormones. Right side shows aerial imaging of residential and retail development (arrow) encroaching into a rural area. These developments are most often initiated by economic potential rather than societal need. Satellite image courtesy of Google 2008 Tele Atlas; photomicrograph courtesy of William Frable, M.D., used with permission.