High Levels of HDL Linked to Increased Risk of Breast Cancer

It is known that high levels of high density lipoprotein (HDL) protects against heart diseases, but a latest study claims that high levels of this 'good cholesterol' can increase breast cancer risk.

The new study, conducted by researchers at Thomas Jefferson University, claims that high levels of high density lipoprotein increase the risk of breast cancer. HDL has also been linked to enhanced cancer aggressiveness in animal experiments. In this study, researchers discovered that HDL receptors present on breast cancer cells play a key role in advancing the disease. With this discovery, the team proposes a new molecular target that could help in treating the cancer.

"If we can block the activity of the HDL receptor in breast cancer, we may be able to limit the harmful effects of HDL, while maintaining levels that are beneficial for blood vessels," lead researcher Philippe Frank, Ph.D., a cancer biologist in the Department of Biochemistry and Molecular Biology at Thomas Jefferson University, said in a statement.

To study the effect of HDL on cancer cell at the molecular level, researchers exposed the breast cancer cell lines to HDL in an experimental model. They found that signalling pathways involved in cancer progression were triggered in the presence of HDL and the affected cells started migrating as they do in metastatic condition.

The team then restricted the expression of HDL receptor called SR-BI in the cells with the help of RNA. They noticed that a drop in the activity of signalling pathways increased tumor progression.

Also, cells with fewer SR-BI levels were linked with reduced tumor formation in mouse model. Blocking SR-BI receptor in breast cancer cell line with BLT-1 drug led to drop in both protein-associated tumor signalling as well as tumorigenesis.

Dr. Frank concluded saying, "Also, we need to understand what levels of cholesterol are required by the tumor before trying to reduce or modify lipid levels in cancer patients. We hope this study will lead to the development of new drugs targeting SR-BI or cholesterol metabolism and eventually preventing tumor progression."

The study is published in the journal Breast Cancer Research.