Multi-marker pathology cancer tests likely to be developed from this research
Pathologists and other clinical laboratory scientists can expect to see a number of multi-biomarker genetic tests for cancer as a result of research that is identifying specific gene abnormalities that are common to certain cancers and promote the growth of these cancers. Variations in these mutations make a difference in the effectiveness of certain treatments.
With the aid of recent advances in genomic mapping technology, an international team led by researchers at the Dana-Farber Cancer Institute and the Broad Institute have found that many of these aberrations in the genetic code are shared by a variety of cancers occurring in many different types of tissues. The study appears in the February 18 issue of Nature.
Beginning in 2004, researchers systematically mapped the genetic abnormalities of 26 different kinds of cancer from more than 2,500 specimens they collected, as well as 800 specimens that were publicly available. They looked at somatic copy-number alterations (SCNAs), in which segments of the tumor’s genome are either amplified (having more than the normal two copies) or missing, which is called a deletion.
In particular, they studied a type of SCNA known as short, or focal SCNA. This SCNA contains about 1.8 million genetic letters, or about 0.03% of the human genome. These compact segments facilitate the task of identifying important cancer genes.
Using recently developed genomic “chip” technology, they created a catalog of the abnormalities found across the specimens. The catalog revealed that that most of the SCNAs occurred in more than one type of cancer. The specimens included cancers of the lung, prostate, breast, ovaries, colon, esophagus, liver, brain and blood.
Matthew L. Meyerson, M.D., Ph.D., of the Dana-Farber Cancer Institute and the Broad Institute of Harvard told Reuters, “A lot of the events that cause cancer are common between cancers of different tissue types. You have breast cancer, lung cancer, cancer of the kidney—many of the events that cause these cancers are going to be the same.”
This study suggests that, rather than focusing on the tissue of origin of the cancer, developers of future cancer treatments will target the genetic abnormalities that initiate and drive cell growth. Future treatments will likely be used across a broad spectrum of tissue types, depending on the genome of the cancer cells.
Genetic studies of cancer cells will someday be the first step in diagnosing a cancer and determining the best treatment. Instead of naming cancers by their tissue types, such as lung or breast cancer, the disease may be designated by the type of genetic mutation that drives its growth.
Pathology laboratories will be at the nexus of this new approach to treatment, and pathologists will be key members of the oncology treatment team. Identifying the specific varieties of mutation that drive a patient’s cancer will be critical to providing effective treatment.