Bladder cancer (BC) is a very common cancer and it has high mortality rates, especially in late stages. BC is considered as a different disease in various stages and grades. Non-muscle-invasive BC and muscle-invasive BC have different properties. There are some prognostic factors for progression and recurrence rates of BC and we have some risk assessment methods. These factors are based on clinical findings and histopathological properties. We do not know which factors and molecular processes are effective in the invasion mechanism. In this review, we summarized possible invasion mechanisms of BC.