Inactivating the JNK pathway by expressing a dominant-negative form of JNK (basket, bsk), depleting Mmp2 (but not Mmp1) or expressing the tissue inhibitor of metalloprotease (timp) in EBs of Sox21a flies reduced tumour burden and growth towards the lumen (Fig. 6c–f). The gene discussed is MAPK8; the disease is neoplasm.