Since AGR2 has been detected in the body fluids from cancer patients (Chevet et al., 2013) as well as in the conditioned media from pancreatic and prostate cancer cells (Arumugam et al., 2008; Zhang et al., 2005), we hypothesized that tumor organoids may also secrete AGR2 (extracellular AGR2 / eAGR2). Here, AGR2 is linked to prostate cancer.