CHL1 and sarcoma: Approaches have included targeting antigens expressed on sarcomas with ADCs, such leucine-rich repeat containing 15 (LRRC15; ref. 32), glycoprotein nonmetastatic b protein (GPNMB; ref. 33), and neural cell adhesion molecule (NCAM, CD56; ref. 34) plus a membrane type 1–matrix metalloproteinase (MT1-MMP) bicycle toxin conjugate (21).