PFKFB3 and tongue cancer: Our data are in line with the results of recent study [21], which reported circadian control of PFKFB3 mRNA levels in human tongue carcinoma cells, with increased levels in the early light (passive) phase of a 24 h day, with peak levels between ZT5 and ZT9 (ZT = Zeitgeber Time, ZT0 indicates the beginning of the light phase), and lowest levels between ZT17 and ZT21.