Granzyme B

Granzyme B (GrB) is a serine protease primarily present in natural killer cells and cytotoxic T cells, which can induce cell apoptosis by activating the Caspase cascade reaction or cracking α microtubule protein. In clinical practice, GrB is highly expressed in NK/T cell lymphoma but lowly expressed in B cell lymphoma and peripheral T cell lymphoma. Moreover, tumor infiltrating lymphocytes (TILs) counting based on GrB staining can reflect the tumor immune activity of patients, and its low expression is related to the proliferation and metastasis of lung cancer, colorectal cancer and breast cancer. Meanwhile, GrB in ovarian cancer can promote the transformation of tumor associated macrophages into M1 type by activating the NF-κB signaling pathway, thereby forming protective immune microenvironment. However, some research suggested that GrB can be expressed in the normal mucosa of gastric cancer and participate in the malignant cell transformation. GrB in urothelial carcinoma may also induce epithelial-mesenchymal transition (EMT) by degrading the extracellular matrix, leading to higher invasiveness of cancer cells.