Mast cells were reported to promote the growth of endothelial cells and angiogenesis by either producing heparin or releasing lysozyme to dissolve the surrounding stromal tissue and then promote tumor growth and metastasis.319,320 Certain substances in the granular composition of mast cells could also promote collagen lysozyme produced by fibroblasts and tumor cells, and indirectly caused the disintegration of collagen, thus promoting tumor invasion and metastasis.329. This evidence concerns the gene LYZ and neoplasm.