The authors speculated that the modest antitumor activity of SGN-30 in ALCL with almost no effect in cHL patients may reflect the limited number of CD30+ HRS cells accessible in cHL tumors which are significantly less per tumor volume when compared with the homogeneous expression of CD30+ lymphoma cells in ALCL tumors. The gene discussed is TNFRSF8; the disease is classic Hodgkin lymphoma.