Some TICs are more resistant to anti-tumor drugs than gastric tumor cell lines and other TICs.

<p>HGC-1, HGC-2 and HGC-4 tumor cells, and MKN45 and MKN74 tumor cell lines are seeded on day 0, treated with various concentrations of (A) doxorubicin, (B) 5-fluorouracil, and (C) doxifluridine from days 1 to 14, and cell numbers on day 14 are determined by MTT assay. Black and blue asterisks show that HGC-1 and/or HGC-4 cells are significantly (**, P<0.01; *, P<0.05 by Student’s t-test) more resistant to the drugs than MKN45 and MKN74 cell lines, respectively, while pink and brown asterisks indicate that HGC-4 cells are significantly (**, P<0.01; *, P<0.05 by Student’s t-test) more resistant to the drugs than HGC-1 and HGC-2 cells, respectively.</p>