New findings shows that a non-clear cell form of kidney cancer known as papillary RCC, which accounts for 12 percent of all RCC, responds differently to sunitinib -- a standard frontline treatment for RCC. In a small but decisive Phase II trial, the researchers found that sunitinib was not effective in patients with this form of the disease. The terms clear- and non-clear cell refer to the general appearance of the cancer cells under a microscope.