It has been known since the 1970s that CHOS have anti-tumor effects [18], and there is also
evidence for positive effects of CHOS in reducing metastasis from tumors [19,20]. It was first
suggested that the anti-tumor activity was due to the cationic properties of CHOS [18]. Later, MW also
was proposed to play a major role [136]. Maeda and Kimura [137] found that CHOS enhanced the
natural killer activity in intestinal intraepitelial lymphocytes at the same time as they reduced tumor
growth in mice, and suggested that this CHOS-activation of intestinal immune functions could be
useful in treating tumors.