Apart from the biological factors, comparisons among different methods published in the literature can be difficult because of the different CpG sites analyzed, different cutoff values also for the same method, heterogeneous tumor samples, lack of quality assurance of the method, and lack of validation of results in independent cohorts.32 In view of the widespread discordant results between locally and centrally analyzed tumors,26 for correct interpretation of the results of clinical trials it seems essential that central MGMT analyses with one method be performed. This evidence concerns the gene MGMT and neoplasm.