Painting a molecular picture of breast cancer

In a new study, led by Janne Lehtiö (SciLifeLab/Karolinska Institutet), researchers from SciLifeLab, University of Oslo, and MD Anderson Cancer Center have generated a detailed map of protein levels in breast cancer tumors. This molecular map complements the DNA and RNA picture of breast cancer and sheds light on how different mutations give rise to changes on the protein level.

Breast cancer is the most common cancer type amongst women and in Sweden alone 7800 women are diagnosed every year. Despite advances in treatments and diagnostics, 1400 women died in 2017.

With proteins being the main cancer drug target, information about protein levels can be vital when selecting the best treatment for each patient. The study also found new tumor specific proteins which could potentially work to develop new immunotherapeutic treatments.

In the study almost 14 000 proteins from tumor tissue were quantified. The result confirms known tumor sub types, but further subdivide these suggesting that the current classification is incomplete.

“How mutations affect the complete library of proteins is poorly understood” says Janne Lehtiö, and adds “We can see that adding protein level information is like moving from a blurry picture to a high resolution image of the cancer molecular landscape”.

“Proteins from part of the genome, not thought to be translated, was also identified. This is extremely interesting since these novel proteins can function as tumor specific antigens and be used in immunotherapy treatment” adds Henrik Johansson, first author on the paper published in Nature Communications 2019.

To help other researchers the authors shared their data in a user friendly data portal with analysis tools.