The immune system cells produce a protein called interleukin-6 (IL-6) that contributes to the overgrowth of lymphatic cells and leads to many of the signs and symptoms of Castleman disease.

CNN: Castleman disease

Recently, it has been marked by structural tensions, as the writers struggle to contain an overgrowth of subplots an unfortunate side effect of their remarkable world-building skills.

NEWYORKER: Net Gain

But the cuckoo traditionally parasitized on meadow pipits on the common which had largely gone because of overgrowth, she said.

BBC: Birdwatcher gave 1922 cuckoo clue