Cancer (or a tumour) is a form of uncontrolled cell growth.
Low levels of methylation in cells can cause uncontrolled cell growth, errors, and cancer.
Cells read the DNA code to manufacture new proteins
When methylation in DNA is low they’re getting more instructions than usual do meaning more genes in the DNA are exposed and can be read all at once. They start following too many instructions, conflicting instructions, causing uncontrolled growth, mutations, and abnormalities.
Regular methylation keeps most instructions locked tightly so the cell can’t read all instructions all at once.