EZH2 and cancer: More and more EZH2 inhibitor drugs are awaitedin the near future;however, such agents are not free of drawbacks: they have proven efficacyin a limited subset of cancers, mainly in Y641 or A677 mutant lymphomacells, and their prolonged administration aroused different adaptivecancerous response mechanisms, such as activation of the insulin-likegrowth factor 1 receptor (IGF-1R), MEK, and phosphoinositide-3-kinase(PI3K) pathways, that ultimately restricted the overall clinical outcome.51