DDX53 and neoplasm: Mice bearing β-gal antigen positive CT26.CL25 tumors in both legs, which had only one tumor illuminated, demonstrated a remarkable and interesting response: the PDT treated tumors regressed in all cases; in 9 out of 10 mice the distant untreated tumors also shrank and disappeared for at least 20 days, while in one mouse the tumor continued growth unabated.