Final answer:
Hypermethylated heterochromatin can silence oncogenes.
Step-by-step explanation:
True. Hypermethylated heterochromatin can silence oncogenes. In cancer cells, there are characteristic modifications to histone proteins and DNA that are associated with silenced genes. The DNA in the promoter region of silenced genes is methylated, and histone proteins that surround that region lack the acetylation modification. This combination of DNA methylation and histone deacetylation leads to gene silencing, including the silencing of oncogenes.