CLDN4 and prostate cancer: Also, we and others have shown that claudin-3 (Cldn3) and claudin-4 (Cldn4) are overexpressed in prostate cancer cells compared to normal prostate cells [14, 16, 17] [Martin DT, Lee JS, Liu Q, Galiana G, Sprenkle PC, Humphrey PA et al.: Targeting prostate cancer with clostridium perfringens enterotoxin functionalized nanoparticles co-encapsulating imaging cargo enhances magnetic resonance imaging specificity, Submitted].