BMP4 and colorectal cancer: BMP-4 plays an important role in the differentiation and proliferation of neural41, and colorectal cancer stem cells42 and is a critical component in regulating hematopoietic stem cell function.43 The involvement of cysteine cathepsins in the migratory potential and differentiation of stem cells was studied before.44 Our results imply that CTSH might be important in the processes of stem cell differentiation by regulating the expression of BMP-4.