The in vivo metabolism of RGD-ICG was similar to that observed in the study by Ito et al. [35], wherein epidermal growth factor receptor-ICG and carcinoembryonic antigen-ICG were synthesized for the diagnosis of peritoneal carcinomatosis from gastric cancer and for which it was found that the probe could be retained in tumors for approximately 7 days whereas excessive probes were excreted from the body within 24 h. This evidence concerns the gene CEACAM5 and gastric cancer.