EPIGENETIC PHENOMENA ARE CRITICAL IN GENE EXPRESSION...
It is now clear that the DNA expression is clearly an important parameter in the destiny of the cell, be it normal or cancerous, the cell destiny is determined by its potential forces built in its DNA.  But as the cell live, there are phenotypic influences imposed by postranslational modifications brought on by epigenetic events which ultimately shape further DNA expression.
These events have been described by others
and include:
1.Histones Modification
2.DNA Methylation or lack of!(Hypomethylation)
3."Nucleosome positioning"
4,Activity of MicroRNA
5.Gene to Gene suppression of expression
we will discuss each as it is pertinent.
But please don't believe that this all.  Indeed:
1.Abnormal Splicing (Frame shift)
2.Point Mutations
3.Disabling of DNA repair
4.Gene cross-talking
5.Enzyme deficiency and
6. Alteration of Homeobox Molecule and arrangements therein ...
WILL ALL AFFECT DNA EXPRESSION AND POTENTIALLY BE A DRIVING FORCE TO ABNORMALITY IN THE CELL!