Based on the results of immunoreactivity with the anti-HO-1 antibody of detergent-extracted species (Figure 5A,E and Figure 6A,E), it can be assumed that both the control and the DS-exposed breast cancer cells contain a significant amount of a component with a molecular weight of ~28 kDa, which is presumably a truncated form of HO-1, in addition to a much smaller level of the 32 kDa component, which likely corresponds to the full-length protein [24,32]. This evidence concerns the gene HMOX1 and breast carcinoma.