Sputum consists of a complex mixture of mucus from the lungs and a variety of cell types including cancer cells if a tumor is present. Sputum can be collected non-invasively with no patient side-effects which makes it an ideal specimen for diagnostic purposes. Sputum cytology was for decades the only tool available to diagnose lung cancer.
Porphyrins are dynamic molecules involved in many biological processes, including oxygen and electron transport. Porphyrins have also been known to incorporate more readily into cancer cells compared to non-cancerous cells, and this property of porphyrins is being explored for diagnostic and therapeutic applications in cancer patients.
The clinical study demonstrated 81% accuracy in detecting cancer from sputum samples collected from participants in two cohorts. The high-risk cohort included military veterans who had smoked at least 20 pack-years.