A Simple Blood Test Will Make Lung Cancer Diagnosis More Effective

An Israeli-British team of scientists has developed a new method for diagnosing lung cancer that, they say, will allow for the detection of one of the most dangerous forms of oncology much more effectively than existing methods. This involves a simple blood test based on DNA repair indicators. These indicators, as researchers have proven, can become a reliable biomarker for lung tumours.

Lung cancer ranks first in the structure of morbidity and mortality from oncology worldwide. According to the World Health Organization, this type of malignant tumour is diagnosed in nearly two million people each year, with over 80% of them dying within the first year after diagnosis.

The critical number of fatal cases in lung cancer is due to its high aggressiveness—such tumours metastasize quickly, affecting vital organs—and late detection: often the disease is identified when it has already spread throughout the body, leaving the patient with little chance of recovery.

The reason for this is the lack of effective diagnostic tools that would allow for the detection of the dangerous disease at an early stage of development. Current methods, including X-rays, biopsies, and sputum tests, mostly yield false or inaccurate results. For example, computed tomography, which is most often used for patients suspected of having lung cancer, shows the presence of a neoplasm in only 25% of cases.

Early diagnosis in lung cancer—just like in any type of oncology—is critically important and can significantly increase the survival rate of patients with this diagnosis. Improving the accuracy of cancer risk assessment for identifying individuals predisposed to lung cancer, which is currently primarily based on two indicators—age and smoking history—is also of great importance and can be a key factor for the early detection of the disease.

However, even an accurate risk assessment, according to Israeli and British scientists, does not always guarantee 100% detection of the tumour. As an alternative solution, they propose using a simple blood test based on DNA repair indicators, which, as a recent study published in the medical journal National Cancer Institute-Cancer Spectrum has shown, is highly effective in screening for lung cancer.

During the study, the scientists found that DNA repair indicators, which summarize the activity of three repair enzymes (specific cell enzymes involved in the DNA repair process)—OGG1, MPG, and APE1—through which cells respond to genetic damage, "can significantly improve the prediction of lung cancer risk, facilitating its early detection."

The participants in the study were divided into two groups: an experimental group consisting of 150 British patients with non-small cell lung cancer and a control group made up of 143 healthy volunteers. "We calculated the total DNA repair indicator for each participant based on the activity level in the blood of three enzymes known to respond to genomic damage," said scientists from the Weizmann Institute of Science.

They found that the DNA repair indicator in lung cancer patients was lower than that of all control group participants, which allowed establishing this enzymatic activity as a reliable biomarker for lung cancer risk, regardless of whether the person is a smoker or not.

The results confirmed the findings of a previous study published in 2014 by Israeli professor Avi Livne, in which he studied DNA repair indicators among the Israeli population. It demonstrated that the new approach could potentially be used for more effective lung cancer screening worldwide.

"Relying solely on age and smoking status as the two main risk factors is incorrect, as they are often insufficient," the scientists note. "This is evidenced by the results of preventive screenings of individuals included in the risk group based on these factors, which miss most lung tumours. Moreover, people who are not obvious candidates for screening remain unaware of the dangers they may face, leading to delayed treatment and poorer prognosis."

In an earlier study, Professor Livne and his team demonstrated that a low total DNA repair indicator is at least five times more effective at determining the risk of lung cancer than considering only age and smoking history. It may also help explain why some non-smokers, who are usually not sent for preventive screening, develop lung tumours, thus contributing to the development of clinical criteria indicating the need for early diagnosis among non-smoking individuals, the scientists from the Weizmann Institute of Science noted.

In their current study, the Israeli-British team also found that a low DNA repair indicator, observed only in patients with lung tumours and not in healthy individuals, is associated with a significant increase in the expression pathways of genes involved in the formation of the body's immune response.

"This also indicates that DNA repair indicators, which are easily established through a blood test, could potentially contribute to the development of personalized therapy, helping doctors predict how a specific lung cancer patient will respond to immunotherapy," the scientists noted.