Trolox increases diploid population and antagonizes conversion to higher ploidy. (A) The frequency of diploid total CICs cultured in 21% O₂ is significantly increased when treated with Trolox in a dose-dependent manner. (B) The frequency of Lin28^{S  +} CICs and polyploidization in total CICs cultured in 21% O₂ is significantly decreased when treated with Trolox in a dose-dependent manner. (C) The ploidy of Lin28^S+ CICs cultured in 21% O₂ is unchanged with Trolox. (D) The size of Lin28^S+ CICs treated with Trolox in a dose-dependent manner is significantly larger based on ploidy content. (E) The frequency of diploid Lin28^S− CICs cultured in 21% O₂ is significantly increased when treated with Trolox in a dose-dependent manner. (F) The size of Lin28^S− CICs treated with Trolox in a dose-dependent manner is relatively unchanged based on ploidy content. Statistical significance (*P < 0.05, **P < 0.01, ***P < 0.001) was determined by one-way ANOVA (A, C–F) for all groups (N = 4).