Yes, but the Alpha kids are also not a part of a "normal" session, and my statement was that a "normal" session would absolutely have a tumor, though I admit that I think the anon who I am trying to refute is a little confused. The TUMOR in the kid's session is a game element present in all games. Karkat talks about giving their universe cancer by fucking up, which is a metaphor for the sequence of events leading to Bec Noir's creation, I think.