As to spontaneoustumors (Table 5, dark grey shaded rows), long-term use of troglitazoneincreased tumor formation, whereas PPARγ reductionhad no effect; (2) a reduction of PPARγ doseby itself (Table 6, light grey shaded rows) is insufficient to induce spontaneoustumor formation, but in existing tumors, it either exacerbates tumor formationor have no effect at all; (3)TZDs (Table 6, un-shaded rows), in most cases, inhibits tumorformation with a rare exception of Apc+/Min mice. Here, APC is linked to neoplasm.