FOXO3 and cancer: Furthermore, FOXO3 is essential for cluster of differentiation-44 (CD44) expression and cancer stem cell (CSC) properties, and inhibition of FOXO3 by cyclic guanosine monophosphate (cGMP) 297 as well as through FOXO3/LKB1/AMPK/PGC-1β (peroxisome proliferator-activated receptor gamma, coactivator 1 beta)/PDHA1 (pyruvate dehydrogenase E1 subunit alpha 1)/CD44 axis influences the CSC phenotype of PC cells 300.