Chemokine (C-X-C motif) ligand 13 (CXCL-13) is elevated in 5-fluorouracil (5-Fu) resistant (5-FuR) colorectal cancer cells. (A, B) Viability of DLD-1 and DLD-1 5-FuR cells, HCT116, and HCT116 5-FuR cells treated with different concentrations of 5-Fu for 3 days. (C, D) Viability of DLD-1 cells or HCT116 cells treated with different concentrations of 5-Fu for 3 days after pretreatment with DLD-1 5-FuR or HCT116 5-FuR cells conditioned medium (CM) for 2 days. (E) Semi-quantitative of cytokine arrays analysis of expression levels of different cytokines measured in the CM of paired DLD-1 and DLD-1 5-FuR cells. (F, G) Box-plot showing the CXCL-13 expression level in colorectal cancer parental cells (DLD-1, HCT116) and 5-FuR cells (DLD-1 5-FuR, HCT116 5-FuR). Data from three independent experiments were tested in triplicate. *p < 0.05, **p < 0.01, ***p < 0.001 by Student’s t test.