IGHE and neoplasm: Despite marked difference in absolute tumor uptake of the two antibodies, their tumor-to-blood (T/B) and tumor-to-muscle (T/M) ratios were similar (T/B: IgE: 11.5 at 48 h c.f. IgG: 9.0 at 72 h; T/M: IgE: 21.1 at 72 h c.f. IgG: 27.8 at 48 h) (Figure 5a,b).