> ...there have been reports of the deregulation of epigenetic modifications, such as the expression of lysine specific demethylase (LSD1) [[5](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5464804/#R5)] [https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5464804/#R17](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5464804/#R17) Study in question: [https://pubmed.ncbi.nlm.nih.gov/21531005/](https://pubmed.ncbi.nlm.nih.gov/21531005/) > Lysine-specific demethylase 1 is highly expressed in solitary fibrous tumors, synovial sarcomas, rhabdomyosarcomas, desmoplastic small round cell tumors, and malignant peripheral nerve sheath tumors (2011) > > By analyzing a total of 468 tumors, we describe for the first time high lysine-specific demethylase 1 expression in several highly malignant sarcomas, including synovial sarcomas, rhabdomyosarcomas, desmoplastic small round cell tumors and malignant peripheral nerve sheath tumors > > Among the intermediate tumors only solitary fibrous tumors were found to be highly lysine-specific demethylase 1 positive, whereas lysine-specific demethylase 1 expression was low or absent in benign tumors. Lysine-specific demethylase 1 inhibition with small molecule inhibitors resulted in growth inhibition of synovial sarcoma cells in vitro and an increase in global H3K4me2 methylation. ... > Our results suggest that dysregulation of lysine-specific demethylase 1 is associated with highly malignant sarcomas proposing them as molecular tumor markers as well as targets for the treatment of these tumor types. ... MAOI's inhibition of LSD1 - ### 3.2. Inhibition of LSD1 impairs cell growth in vitro > LSD1  belongs to a large family of FAD-utilizing amine oxidases. These include polyamine oxidases and MAOs. Monoamine oxidase inhibitors (MAOIs) are a class of small-molecule inhibitors of the MAO family,  which reversibly and irreversibly inhibit various MAOs and are in  clinical use for treatment of depression and Parkinson's disease. > > We  investigated whether inhibition of LSD1 leads to cancer cell growth inhibition. Therefore, we tested several synovial sarcoma cells lines. Treatment of the synovial sarcoma cells Fuji, CME-1, HS-SY-II and SYO-1  with the irreversible MAOI tranylcypromine, and the reversible MAOI chlorgyline impaired cell growth in a dose-dependent manner ([Fig. 3](https://www.sciencedirect.com/science/article/pii/S0046817711000499?via%3Dihub#f0015)A). Reduced viability was accompanied by increased global dimethylation of lysine 4 in histone 3 (H3K4me2, [Fig. 3](https://www.sciencedirect.com/science/article/pii/S0046817711000499?via%3Dihub#f0015)B) indicating that the enzymatic function of LSD1 is indeed inhibited. ![[1-s2.0-S0046817711000499-gr3.jpg]] Note very high dosage is this relevant? Where is control? Tranylcypromine antidepressant - After a 20 mg dose, plasma concentrations reach at most 50-200 ng/mL.[[11]](https://en.wikipedia.org/wiki/Tranylcypromine#cite_note-pmid28655495-11) While its [half-life](https://en.wikipedia.org/wiki/Biological_half-life "Biological half-life") is only about 2 hours, its pharmacodynamic effects last several days to weeks due to irreversible inhibition of MAO.[[11]](https://en.wikipedia.org/wiki/Tranylcypromine#cite_note-pmid28655495-11)