Tail vein metastasis assay

6- to 8-weeks-old BALB/c mice were from National Laboratory Animal Center (Taiwan) and were randomized into experimental groups before implantation of tumor cells. One million cells were suspended in 100 µl PBS, and then injected into mouse tail vein, and mouse organs were harvested after cardiac perfusion with PBS. Mouse organs were fixed with paraformaldehyde, paraffin-embedded, and sectioned for hematoxylin and eosin (H&E) staining. For quantification of GFP-expressing cancer cells, mouse organs were subjected to RNA extraction for detection of GFP RNAs by real-time RT-PCR. The BALB/c mice were provided by the National Laboratory Animal Center (Taiwan). All animal studies were approved by Institutional Animal Care and Use Committee (IACUC) of National Health Research Institutes and all methods were carried out in accordance with the relevant guidelines and regulations (NHRI-IACUC-105127).