While cAMP-PKA axis fulfills all basic requirements as a candidate for the intracellular signal that modulates cancer cell survival under glucose starvation, as shown by our experiments using the PKA and Epac inhibitors (panels B, C and D in S10 Fig and panel F in S12 Fig), we still cannot completely exclude that also Epac branch mediates some cellular response. The gene discussed is RAPGEF3; the disease is cancer.