Question: Is cancer related to global DNA hypo or hypermethylation?

Context:
Regions of focal DNA hypermethylation and long-range hypomethylation in colorectal cancer
Regions of focal hypermethylation in the tumor were located primarily at CpG islands and were concentrated within regions of long-range (>100 kb) hypomethylation. These hypomethylated domains covered nearly half of the genome and coincided with late replication and attachment to the nuclear lamina in human cell lines
the confluence of hypermethylation and hypomethylation
Comparison of CpG island hypermethylation and repetitive DNA hypomethylation in premalignant stages of gastric cancer
CpG island hypermethylation and genomic DNA hypomethylation are found not only in gastric cancers but also in associated premalignant lesions
Methylation of repetitive DNA elements in gastric lesions generally decreased with progression of the gastric lesion along the multistep carcinogenesi
our findings suggest that CpG island hypermethylation and repetitive DNA hypomethylation are enhanced with progression of the gastric lesion
DNA hypomethylation arises later in prostate cancer progression than CpG island hypermethylation
Hypomethylation of CpG dinucleotides in genomic DNA was one of the first somatic epigenetic alterations discovered in human cancers. DNA hypomethylation is postulated to occur very early in almost all human cancers, perhaps facilitating genetic instability and cancer initiation and progression.
Contrary to the prevailing view that global DNA hypomethylation changes occur extremely early in all human cancers, we show that reductions in (5me)C content in the genome occur very late in prostate cancer progression, appearing at a significant extent only at the stage of metastatic disease
These findings provide evidence that DNA hypomethylation changes occur later in prostate carcinogenesis than the CpG island hypermethylation changes and occur heterogeneously during prostate cancer progression and metastatic dissemination.
revealed a high incidence of hypermethylation only in poorly differentiated (early and late) tumors.
In contrast to gene hypermethylation, genomic DNA hypomethylation, including hypomethylation of repetitive elements and loss of genomic 5-methyldeoxycytidine, occurred in both early and late stages of prostate cancer.
Tumors have reduced levels of genomic DNA methylation and contain hypermethylated CpG islands
The results are consistent with a specific defect in methylation of repetitive DNA sequences in human cancer.
Both hypomethylation and hypermethylation in a 0.2-kb region of a DNA repeat in cancer
Differential DNA hypermethylation and hypomethylation signatures in colorectal cancer
Cancer cells are characterized by a generalized disruption of the DNA methylation pattern involving an overall decrease in the level of 5-methylcytosine together with regional hypermethylation of particular CpG islands
We conclude that DNA hypermethylation and hypomethylation are independent processes and appear to play different roles in colorectal tumor progression

Answer: DNA hypermethylation and hypomethylation are independent processes and appear to play different roles in tumor progression.  Cancer cells are characterized by a generalized disruption of the DNA methylation pattern involving an overall decrease in the level of 5-methylcytosine together with regional hypermethylation of particular CpG islands. Tumors have reduced levels of genomic DNA methylation and contain hypermethylated CpG islands.
Exact answer: Global hypomethylation is coupled with focal hypermethylation at CpG islands