MAPK8 and neoplasm: Additionally, genetic screens of scrib mutant RasV12-expressing tumours have revealed the importance of the PI3K signalling pathway [67], and chemical screens have revealed the importance of glutamate utilization enzymes, the TCA cycle, and pyrimidine synthesis [68] for tumour growth. scrib mutant RasV12-expressing tumours, in a JNK-dependent manner, upregulate the diffusible Insulin-like peptide, dILP8 [69].