TYRP1 and glioblastoma: Similarly, CatB was reported to be upregulated after the differentiation of monocytes into tissue macrophages, but not earlier in hematopoetic differentiation49 and CatL expression was upregulated during angiogenesis from endothelial progenitor cells.50 These results suggest that GBM stem cells are not as invasive as their progenitors, losing CD133 and acquiring migratory properties by activation of a set of proteolytic enzymes, including Cats.