Interestingly, although Hep2 cells did not express uPA or MMP activity sufficient for intercomplementing toxin activation in culture (see above), the Hep2 tumors were treated efficiently in vivo, with the average tumor size of toxin-treated mice being just six percent of the average tumor sizes of PBS-injected mice at treatment cessation (Figure 2D). The gene discussed is PLAU; the disease is neoplasm.