IP6K2 and obesity due to melanocortin 4 receptor deficiency: Another kinase responsible for the production of IP7, IP6K2 has also been implicated in tumor biology.46,47 IP6K2 is a regulator of apoptosis, affecting signaling through Akt and p53.48–50 Deletion of IP6K2 predisposes to certain carcinomas51 and has been shown to sensitize tumors to chemotherapeutic treatments.52,53 Future studies are needed to determine if this interesting group of molecules can be modulated to affect the coupling of obesity and the carcinogenic process.