H2AX and hyperinsulinism: Interestingly, the number of cells with γ-H2AX foci decreased after 6 h indicating possible activation of repair pathways (Fig. 7b) as MDA-MB-231 cells harbor wild-type BRCA1. To investigate whether hyperinsulinemia is associated with increased histone acetylation and DNA damage in human samples, we measured the levels of H3K9ac and γ-H2AX in peripheral blood mononuclear cells (PBMCs) from an insulin-resistant and a healthy individual.