MGMT and neoplasm: Our main focus was on (1) the degree of the MGMT promoter methylation changes caused by TMZ and their potential implications for further TMZ response; (2) the examination of changes in the tumor cell behavior, such as migration, proliferation, and metabolism, based on the treatment; (3) the evaluation whether and how these changes were dependent of the CSCs’ molecular profile (high or low MGMT promoter methylation); and (4) the identification of differences between cells treated by various treatment schemes.