Since genes from cancer cells are hypomethylated are we sure that the hypomethylation is the cause of the malignancy or a consequence of the cancer cells possessing altered metabolism?

Medical toxicology

Many cells exposed to chemicals experience hypomethylation and this enhances cell transformation. Since genes from cancer cells are hypomethylated are we sure that the hypomethylation is the cause of the malignancy or a consequence of the cancer cells possessing altered metabolism?