Breast Cancer, Genes, and Environment

Breast cancer treatment may be explained by epigenetics

(RxWiki News) “Baby, you were born this way” is a newer phrase coined by Lady Gaga - for the most part you were born with a set of genes that make you look a certain way. Maybe not though!

The best representations of identical genes in humans are identical twins. For the most part, twins are completely identical when it comes to genes, but there are some twins that don’t look the same at all and that could be due to epigenetics. The environment impacts the way genes are expressed.

Epigenetics may also play a role in breast cancer. There are different subtypes of breast cancer and researchers suggest that these different subtypes show different methylation patterns in response to epigenetics. (DNA methylation is a genetic process that ends up reducing the expression of a gene.)

"Epigenetics may be able to help detect and treat breast cancer."

Dr. Sarah Dedeurwaerder from Universite Libre de Bruxelles studies the epigenetic differences between normal tissue and tumor samples. Epigenetics affects genes in the way they are expressed by DNA methylation. Genes that are methylated are not expressed and vice versa.

Different samples of human breast tissue were analyzed and separated into two subtypes: Estrogen receptor (ER) positive and ER negative. Dr. Dedeurwaerder found that the different subytpes show different methylation profiles. Every person has their own unique methylation patterns on their genes, which may contribute to how each person reacts differently to treatment.

Researchers also found that expression of the ER gene and methylation had a reverse correlation, which probably suggests that epigenetics is involved in the way the breast cancer appears by ER status.

This research has paved the way to a better understanding of how people with the same subtype breast cancer responds differently to treatment. The DNA methylation markers can provide an earlier detection method and predict the response to a given drug.

The Study

  • Universite Libre de Bruxelles from Brussels
  • 248 samples of human breast tissue examined; samples separated into two groups: ER negative and ER positive
  • Measured DNA-methylation to understand epigenetics
  • ER positive and negative tumors show different DNA methylation
  • Expression and methylation found to be inversely related
  • Epigenetics probably involved in expression of genes
  • New breast cancer subtypes identified with DNA methylation
  • Epigenetics can explain different reactions to treatments in people with same subtype breast cancer
Review Date: 
May 17, 2011