EEF1A1 and cancer: Since the tumorogenic potential of eEF1A1 has been proposed following the observation that its over-expression correlates with increased metastatic potential in mammary adenocarcinoma26, 32, 33, including melanomas, hepatocellular carcinoma, pancreatic carcinoma, breast carcinoma, prostatic carcinoma, cervical carcinoma and bladder carcinoma, some of which were commonly treated by PDT clinically, our finding provide an mechanistic explanation that why PpIX accumulated in cancer cells in 5-ALA based PDT.