Researchers in the U.K. think we’re getting close to a simple blood test that can diagnose all cancers. Early results show how it can identify cancer and pre-cancerous conditions in patients with melanoma, colon cancer, and lung cancer.
By helping doctors rule out certain diseases in people with symptoms, the test could save time and money while preventing the need for painful, invasive procedures like biopsies.
Known as the Lymphocyte Genome Sensitivity (LGS) assay, the test looks at white blood cells called lymphocytes and the damage caused to their DNA when subjected to different intensities of ultraviolet light, which causes damage to genetic material. “White blood cells are part of the body’s natural defense system. We know that they are under stress when they are fighting cancer or other diseases, so I wondered whether anything measurable could be seen if we put them under further stress with UVA light,” Diana Anderson from the University of Bradford explains in a news release.
Anderson and colleagues examined the lymphocyte responses in 208 people: 20 with melanoma, 34 with colon cancer, 4 with lung cancer, 18 with suspected melanoma, 28 with polyposis, and 10 with chronic obstructive pulmonary disease (COPD), and 94 healthy volunteers. The samples were coded, randomized, and then exposed to UVA light through five different depths of agar.
They found a clear distinction between the damage to the white blood cells from patients with cancer, patients with pre-cancerous conditions, and healthy patients. “People with cancer have DNA which is more easily damaged by ultraviolet light than other people,” Anderson says, “so the test shows the sensitivity to damage of all the DNA -- the genome -- in a cell.”
UVA damage shows up in the form of pieces of DNA pulled in an electric field towards the positive end of the field; this creates a tail like the one you’d see trailing a comet. In the LGS test, the longer the comet-like tail, the more DNA damage. The measurements correlated to those patients who were ultimately diagnosed with cancer (58), those with pre-cancerous conditions (56), and those who don’t have cancer (94).
A clinical trial is currently underway to test the effectiveness of the LGS test at predicting which patients would benefit from a colonoscopy.
The work was published in the FASEB Journal last week.
Image: Marcelo Duarte via Flickr CC BY-NC 2.0