Genetics: 4 Kinds of Breast Cancer
This study has gotten a lot of media attention and press time over the past few days. I have heard about it from a number of women, and, per usual, the quick headlines don't do a very good job of presenting the information. As I understand it, researchers have identified four specific kinds of breast cancer, genetically different from one another. The exciting prospect is that, over time (probably over a lot of time) this will enable scientists to develop treatments that are targeted and useful for each kind. Think fewer side effects and damage to healthy cells (including hair!) and more damage to cancer cells. The important reality check is that this is going to take a very long time, and, frankly, may not be of value to those of us now living with breast cancer.
Here is the beginning of thoughtful comments and understandable explanations from BreastCancer.org:
Study Analyzes Breast Cancer Genetics, Finds Four Classes of Disease
Researchers have done the most thorough analysis of breast cancer genetics to date and found that there are four genetically distinct classes of the disease. The research will likely lead to new, more precise treatments for breast cancer, but developing and testing these new treatments is likely to take many years. The research was published online by the journal Nature on Sept. 23, 2012. Read "Comprehensive molecular portraits of human breast tumours."
Genes contain the recipes for the various proteins a cell needs to stay healthy and function normally. Some genes and the proteins they make can influence how a breast cancer behaves and how it might respond to a specific treatment. Cancer cells from a tissue sample can be tested to see which genes are normal and abnormal. The proteins they make also can be tested.
In the study, researchers analyzed the genes in breast cancer tumors from 825 women diagnosed with early-stage breast cancer. The study is part of a larger national project, the Cancer Genome Atlas, which aims to build maps of the genetic abnormalities in common cancers, including breast, lung, and colon cancers.
The study confirmed that there are four main subtypes of breast cancer: luminal A, which is hormone-receptor-positive (either estrogen- and/or progesterone-positive) and HER2-negative luminal B, which is hormone-receptor-positive (either estrogen- and/or progesterone-positive) and HER2-positive basal-like, which is hormone-receptor-negative and HER2-negative (also called triple-negative breast cancer); the researchers found that basal-like breast cancer is much different from the other three types of breast cancer and more closely resembles ovarian cancer and a type of lung cancer HER2-enriched, which is hormone-receptor-negative and HER2-positive.
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