SOD2 and neoplasm: To further examine how MnSOD-K68 acetylation affects the in vitro cell phenotype, we performed colony formation assays where tumor cell growth was determined when plated at low density, a measure of tumor cell proliferative capacity, i.e., 500 cells plated in 6-well plates, and stained with crystal violet after three weeks of culture (colonies required more than 50 cells).