AXIN2 and multiple endocrine neoplasia type 1: On the other hand, Chen G. et al. reported that overexpression of Menin, a tumor suppressor protein mutated in patients with multiple endocrine neoplasia type 1, is associated with increased H3K4 trimethylation of the Axin2 gene promoter; while, inhibition of Menin expression by siRNA abrogates H3K4 trimethylation and gene expression of Axin2, indicating that Menin functions, at least partly, through affecting histone trimethylation of Axin2 promoter (Chen et al., 2008).