The Ki-67 index was significantly lower in GISTs than in non-GIST tumors (median 6% vs. 14%; p = 0.004), and a moderate positive correlation between tumor size and Ki-67 (ρ = 0.42, p = 0.018) indicated that larger lesions tended to exhibit higher proliferative activity, echoing the size- and site-related gradients described by Wang et al. and others [4,13]. This evidence concerns the gene MKI67 and neoplasm.