Stimulatory effect of CHI3L1 on tumor cells in vitro.

A) Purity of recombinant CHI3L1-Flag fusion protein (upper arrow); B) LLC cell proliferation treated with GST or CHI3L1-GST fusion protein; C) The apoptotic activity of LLC cells treated with GST or CHI3L1-GST fusion protein by Annexin V labeling assay. *, p<0.05, **, P<0.01.