Over-expression of the JAK/STAT ligand Upd in testes using tjts-Gal4, together with LacZ as a titration control, resulted in tumors containing many Zfh1-positive CySC-like cells, and an almost complete absence of Eya-positive differentiated cyst cells (Fig 4C and 4D). The gene discussed is LGALS4; the disease is cyst.