To exclude that the anticancer effect of the c-KitW-sh hypomorphic allele was not in part mediated by hematopoietic cells other than mast cells, we generated mast cell-deficient gp130FF; Cpa3-Cre; Mcl1fl/fl gastric cancer mice, where mast cell-specific carboxypeptidase A3 (Cpa3) promoter driven Cre recombinase activity leads to the deletion of Mcl1 prosurvival gene. The gene discussed is CPA3; the disease is gastric cancer.