DNA demethylation can be passive or active. The passive process takes place in the absence of methylation of newly synthesized DNA strands by DNMT1 during several replication rounds – for example, upon 5-azacytidine treatment [23]. These pharmaceutical demethylating agents act via inhibition of DNMT1 and favoring its degradation by proteosomes [24]. This approach is currently used in cancer to demethylate tumor suppressor genes [25].

If we’re demethylating a tumour suppressor gene for cancer curing doesn’t this mean that we’re activating it (to stop the tumours)? I can’t seem to understand the function of DNA demethylation. I came across it when reading about genomic imprinting and haven’t been able to wrap my head around it. Please help.


1 Answer 1


Here is a series of articles explaining DNA Demethylation from Sience Direct.

In the most broadest of senses, DNA methylation adds methyl groups to DNA preventing the transcription complex from forming and transcribing the gene into mRNA. By demethylating the DNA, it allows the transcription complex to form and mRNA to be transcribed for translation.

When it comes to cancer, Most of the tumor suppressor genes are down regulated to allow for genes like stat3 to be upregulated. Ideally, by removing the suppression of these genes, they can reduce the levels of oncogenes and slow the growth of the cancer.

Think of it like this A -| B. Cancer decreases A so B can increase in expression A↓ -| B↑. By demethylating A, we A↑ -| B↓.


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