For instance, CML LSCs establish a bone morphogenetic protein (BMP) autocrine loop to acquire TKI resistance; TKI-resistant LSCs have higher expression of BMPR1b and are associated with overproduction of BMPs by the microenvironment, such as mesenchymal stromal cells, through autocrine (and/or paracrine) mechanisms. Here, BMPR1B is linked to chronic myelogenous leukemia, BCR-ABL1 positive.