Figure 6. PCI of 3–17I-saporin attenuates cellular viability in three different EpCAM-positive cancer cell lines. Viability (MTS) assay of (A) MCF7; (B) BxPC-3; (C) WiDr; and (D) the EpCAM-negative cell line COLO320DM after treatment with PCI of 3–17I-saporin; PCT; PCI of saporin; IT (3–17I-saporin); and 3–17I alone, all relative to no treatment. The MTS assays were performed 96 h after light treatment, following the PCI protocol in section 2.13. Error bars represent standard deviation. Statistically significant difference between PCI 3–17I-saporin vs. PCI saporin (P < 0.05) is indicated by *.