BTK and breast cancer: As to the question of how TREM1 contributes to growth and migration of ADIR, we found that as with myeloid cells, Syk and Btk, which are known to be expressed in breast cancer cells 47-49, are activated in ADIR clones, as are the downstream ERK and PI3K/AKT/mTOR and STAT3 signals 35, 50.