What do epigenetics do for our health?

I'll start off the discussion with this:

Epigenetics allow our bodies to adjust to changes so that we're not expending energy where it is not needed. For example, African nations are amongst hottest and driest on earth. Men and women there are typically hairless on their bodies; one reason for that are genes being turned-off for body hair production. The same can be said for when someone moves from a hotter climate to a colder one. They may experience increased body hair formation due to certain genes being reactivated.

How about concerning cancer? Do epigenetics protect us from genes that may harm us? I am interested in Yamanaka Factors and their potential ability to get rid of harmful epigenetic changes that cause some age symptoms, but don't know if it temporarily removes the muting of a gene that can do harm to us.

According to this illustration (obtained from the source provided below), alterations in epigenetic modifications in cancer regulate various cellular responses, including cell proliferation, apoptosis, invasion, and senescence. Through DNA methylation, histone modification, chromatin remodeling, and noncoding RNA regulation, epigenetics play an important role in tumorigenesis. These main aspects of epigenetics present reversible effects on gene silencing and activation via epigenetic enzymes and related proteins.

DNMTs, DNA methyltransferases; TETs, ten-eleven translocation enzymes; HATs, histone acetylases; HDACs, histone deacetylases; HMTs, histone methyltransferases; HDMs, histone-demethylating enzymes. MLL, biphenotypic (mixed lineage) leukemia.

https://www.lifespan.io/topic/yamanaka-factors/

This was inspiring, but still brings up a number of questions. Particularly since human trials for eye diseases may start in a couple years.