A new proposition has been put forward suggesting that cancer classification must be made according to the molecular and genetic features of the disease rather than just the type of tissue where the tumor has developed. Researchers say that restructuring the cancer classification system would help medical professionals to tailor treatment to the specific needs of individual patients.
The researchers from The Cancer Genome Atlas (TCGA) analyzed over 3,500 types of tumors based on multiple genomic technology platforms, which is the most copious genomic study conducted on cancer to date. What they found is that even tumors that are found on different types of tissues-bladder, breasts, kidneys, or other parts-are more genetically and molecularly similar then initially thought.
The study compared the RNA, DNA and protein contents of over 3,500 specimens from 12 different tumor types. These samples were analyzed over six different platform technologies and the results showed that tumors are even more likely to be genetically and molecularly similar based on their cell origin rather than their tissue origin. As an example they cited bladder cancer, which, they say, should be further classified into subtypes. One subtype of bladder cancer was almost identical to lung adenocarcinoma, while another subtype was the same as squamous cell cancers that often occur in the head, neck, and lungs.
Author, Chris Benz, pointed out that most of the body's tissues are comprised of multiple layers of epithelial and non- epithelial cells, which may account for there molecular and genetic similarities even across tissue types. "This disruptive genomics study not only challenges are existing system of classifying cancers based on tissue type, but also provides an massive new data resource for further exploration as well as a comprehensive list of the molecular features distinguishing each of the new described cancer classes." The researchers say that reclassifying cancers will help medical professionals to provide specific treatment that can result to different and distinct outcomes.