This one may be relevant as well. As to xylitol, tumors, animals and lab experiments there are many other articles on xylitol vs. table sugar.
One example is "Junko Sato,2 Yeu-Ming Wang, and Jan van Eys Department of Pediatrics, The University of Texas System Cancer Center, M. D. Anderson Hospital and Tumor Institute, Houston, Texas 77030". In it lab rats with various pre-existing liver tumors received a 10% IV solution of Xylitol at the rate of 2 g per kg body weight. The researchers found the hepatocellular carcinoma was markedly deficient in the ability to synthesize acid-insoluble glycogen and glycoprotein from xylitol.
Translation: researchers found that (on pre-existing tumors) the xylitol caused significantly less harm than ordinary table sugar. Note the tumors were pre-existing ones. No, they were not caused by xylitol.