How can an RNA virus cause cancer if it doesn't have DNA to insert into a cell's genome?

There are 2 types of RNA virus, ss(single stranded) RNA virus, and ds(double stranded) RNA virus. Even RNA virus which doesn't have DNA molecules can causes cancer by disrupting the activity of the cell, because most of the cell activity are regulated by functional protein, such as various enzymes, and not by DNA or RNA itself. RNA virus could make or express new protein using the cell apparatus and its RNA (remember the translational process), if a RNA virus can make proteins, yes it can cause cancer.