Which of the following is TRUE of methylation in cancer cell

Which of the following is TRUE of methylation in cancer cells?

A

Overall levels of methylation throughout the cancer cell genome often increase.

B

There is an increase in DNA methyltransferase enzyme activity.

C

Areas of CpG islands are hypomethylated.

D

Areas of CpG islands become methylated inappropriately.

E

None of the above.

Solution

B. There is an increase in DNA methyltransferase enzyme activity.

The risk of developing cancer increases with age due to decreased efficiency of repair mechanisms (eg: DNA methylation) during the cell divisions. The epigenetic changes of genes such as DNA methylation affect the gene expression levels and thus, the RNA synthesis. The activity of methyltransferase increases in several of the cancer types, and inhibitors of methyltransferases are tried as anti-cancer drugs.