CSF1R and chronic myelogenous leukemia, BCR-ABL1 positive: Mass cytometry analysis revealed downregulation of CD115/CSFR1 in CML RPMs This is rather surprising since TAM of the M1 type, which are pro-inflammatory and activate the immune system towards a tumoricidal state, are known to be CD115 dependent, whereas M2 differentiated TAMs rely on CD115, suppress immune effector functions and promote tumorigenesis.