CPA3 and neoplasm: Importantly, mast cell-deficient gp130FF;Cpa3-Cre; Mcl1fl/fl mice had significantly reduced tumor mass and tumor number compared to their mast cell-proficient controls (Fig. 2e, f), and this observation coincided with reduced angiogenic vessel density in the tumors of gp130FF; Cpa3-Cre; Mcl1fl/fl mice (Fig. 2g).