Scientists have identified a new molecular marker in blood which could indicate how patients with a type of lung cancer will respond to treatment, according to research published in Clinical Cancer Research.

Researchers at the Physiological Laboratory, University of Liverpool and cancer specialists at Clatterbridge Centre for Oncology found that a molecule called SCG3 mRNA in the bloodstream has a high association with a type of lung cancer called neuroendocrine small cell lung cancer (SCLC).

The marker could be developed for use in blood tests to see how well patients might respond to treatment for this type of lung cancer. The discovery may in future help doctors make more informed decisions about therapy or recommend that patients take part in trials to try new treatments that might be more effective for them.

There are presently no clear biological markers in blood suitable for identifying how well SCLC patients will respond to treatment, so all patients presenting with SCLC - one of the two main types of lung cancer - are usually treated with the same standard form of chemotherapy.

Patients with neuroendocrine SCLC are not usually able to have surgery because of multiple tumours which make operations difficult. Many patients initially respond to chemotherapy and radiotherapy, but their tumours are likely to reoccur, which is why it is so important to ensure that patients receive the optimum treatment for this disease.

Dr Judy Coulson, Cancer Research UK-funded lead author based at the University of Liverpool’s, School of Biomedical Sciences, said: “There are currently no blood-based markers routinely used to monitor patients with this type of lung cancer.

“We found that SCG3 mRNA is an incredibly sensitive marker of these tumours and it could be used to detect circulating tumour cells in patients with this disease.”

Lung cancer is the greatest UK cancer killer – some 33,500 individuals die from the disease in the UK each year accounting for 22 per cent of UK cancer deaths. Progress in improving survival for lung cancer has been very slow especially in comparison to some of the other common cancers such as breast or bowel cancer where survival rates have increased steadily over the past three decades.

Cancer Research UK has launched a five year strategy to reduce cancer death. This will see £300 million spent each year in core areas of science and will include increased investment in those cancers where survival remains poor, including lung, pancreas and oesophageal cancer.

Lesley Walker, Cancer Research UK’s director of cancer information, said: “This discovery is an important step to understanding how to treat lung cancer patients more efficiently. Lung cancer can be very difficult to treat in the later stages, either because it has spread of because there are too many tumours. Chemotherapy is therefore a vital part of lung cancer treatment.

“Anything that improves our knowledge of how to best treat lung cancer is crucial work.”