Second, while paclitaxel is known to be a potent inducer of apoptosis in MCF-7 breast cancer cells, at concentrations enough to increase the frequency of MN-γ-H2AX (−) by at least two-fold, it had no effect on the frequency of MN-γ-H2AX (+) (Table 3). The gene discussed is H2AX; the disease is breast cancer.