We immunohistochemically evaluated the involvement of five cancer cachexia-related factors, including leukemia-inhibitory factor (LIF), zinc-alpha2-glycoprotein (ZAG), interleukin 6 (IL-6), proteolysis-inducing factor (PIF) and tumor necrosis factor alpha (TNF alpha) in causing cancer cachexia. Twenty-six xenografts implanted into mice were examined for the expression of the cancer cachexia-related factors, in relation to the body weight loss of the hosts. Five xenografts were categorized in the cachectic group, and the remaining 21 xenografts belonged to the non-cachectic group. LIF was extensively expressed in both the cachectic and non-cachectic groups. ZAG and IL-6 were expressed in one of the cachectic and some non-cachectic xenografts. PIF and TNF alpha were detected in one and two non-cachectic xenografts, respectively, but in none of the cachectic ones. Any of five factors examined were not conclusive for causing cancer cachexia in the murine xenograft model. Further analysis is needed in order to elucidate the mechanisms responsible for cancer cachexia.