Instigating tumors secrete osteopontin → °granulin producers derived from Sca1+/c-Kit- BMN cells (NOT the Sca1- nor Sca+c-Kit+ fraction) → migrate to responding tumors → °α-SMA+ tumor promoting myofibroblasts at premetastatic niche support tumor cell engraftment. The gene discussed is GRN; the disease is neoplasm.