The lack of anti-tumor effect of the short-term anti-GPC1 mAb treatment against the established orthotopic A549 lung tumors and the profound inhibitory effect of anti-GPC1 mAb on anchorage-independent A549 cell growth in vitro suggest that the effect of anti-GPC1 mAb on preventing tumor development in tumor-bearing mice should be tested using a modified anti-GPC1 mAb dosing regimen. The gene discussed is GPC1; the disease is neoplasm.