García-Martínez A, et al. - Using methylation-specific multiplex ligation-dependent probe amplification and quantitative real-time PCR techniques, researchers assessed the impact of methylation of tumor suppressor genes (TSGs) on their gene expression and on the behavior of pituitary neuroendocrine tumors (PitNETs). Among PitNET subtypes, different methylation patterns were observed. Compared to silent corticotroph tumors, ESR1 and CASP8 seemed more hypermethylated in functioning. Findings suggested that DNA methylation of TSGs has a selective impact on their gene expression and on the growth and invasiveness of PitNETs. Their involvement in their functionality is biased, as all silent operated tumors are macroadenomas, while all operated microadenomas function. Consequently, different entities should be considered the subtypes of PitNETs.