Jun N-terminal kinase signalling inhibits differentiation of Ras85DV12/scrib–/– tumour cells via an unclear mechanism (Figure 3), but it can be observed in the eye imaginal disc tissue due to decreased expression of embryonic lethal abnormal vision (Elav), a marker of photoreceptor cell differentiation, which is restored upon JNK signalling inhibition (Leong et al., 2009). Here, MAPK8 is linked to neoplasm.