Here we found that HB subunits are expressed not only in red blood cells but also in breast muscle corroborating previous studies that have reported HB expression in a wide variety of non-erythroid cells and tissues including neurons (Ohyagi et al., 1994; Biagioli et al., 2009; Schelshorn et al., 2009), macrophage (Liu et al., 1999), eye lens (Wride et al., 2003), and breast cancer cells (Gorr et al., 2011). Here, GSTM1 is linked to breast cancer.