Researchers have developed a method to identify tumor cell DNA in blood samples taken from patients with different types of cancer. Their findings suggest a way to detect early stages of this disease and consequently help guide treatments.
This disease occurs when genes change the way cells grow and divide. In all types of this disease, some of the body’s cells begin to divide without stopping, and then spread into surrounding tissues. It can start almost anywhere among the trillions of cells in the human body.
Each cancer demonstrates a unique combination of genetic changes. As the disease grows, it continues to change. Even within the same tumor, different cells can display different genetic changes. Therefore, it becomes most difficult to treat over time. As such, the ability to detect early genetic changes can help doctors save many lives.
Researchers led by Dr. Victor Velculescu at the Johns Hopkins Kimmel Cancer Center investigated whether they could detect circulating DNA from early tumors.
44 healthy people and 200 patients with different stages and types of the disease provided blood samples. The samples were scanned 30,000 times. Furthermore, this technique results in very accurate detection for changes in the DNA sequence.
Next, blood samples were screened for mutations within 58 known cancer related genes. Results indicated no tumor-derived mutations in the blood samples from the healthy people. On the other hand, tumor related DNA mutations were identified in the blood of cancer patients. Indeed, the technique identified tumor-related DNA mutations in 48 of 62 patients (77%) with advanced cancer (stages III and IV) and in 86 of 138 patients (62%) with stage I or stage II cancer. Most important, these samples came from from patients with colorectal, breast, lung, and ovarian cancer.
This study indicates that identifying this disease early by measuring DNA changes in the blood is feasible. Early detection will increase survival rates.