MTOR and colitis: Everolimus is involved in the first-line systemic treatment of metastatic chromophobe non-ccRCCs.3 It causes grade 3-4 diarrhea (greater than 7 times stools per day and may require hospitalization) in only 1% of metastatic RCC patients, and everolimus-associated colitis is extremely rare.1 The relationship between mTOR inhibitors and CMV infections was studied extensively.