Ras–Raf–MEK1/2 and PI3K–Akt are intracellular signaling pathways which play a crucial role to regulate tumor cell proliferation (Martin, 2003; Osaki et al., 2004), hence the association of a signal pathway with TPL-induced inhibition was examined, using HT-1080 cells. The gene discussed is AKT1; the disease is neoplasm.