Intriguingly, LKB1, a canonical upstream element in TSC1-TSC2-RHEB-mTOR signaling41, is well-established to regulate cell motility and axon growth42, and thus it is possible that TSC1-TSC2 complex-regulated PAK2 activation may be involved in the pathophysiological effects of this important tumour suppressor as well. The gene discussed is TSC1; the disease is neoplasm.