Lung Cancer

Lung Cancer, Toxoplasma gondii, a microscopic parasite that gets inside our cells, is present in about 10% of the population in the UK. But in tests on lung cancer patients, all were find to be infect with the parasite. It’s a remarkable result which we don’t fully understand yet. It is possible that the presence of the parasite in these patients is exacerbating their symptoms of cancer or interfering with their therapy. Geoff Hide, Professor of Parasitology, University of Salford.

Intracellular protozoan parasite

Toxoplasma gondii is an intracellular protozoan parasite; which can be find in all warm blood animals. This parasite can only complete its full life cycle in cats; but nevertheless around 30% of the human population, globally, is estimate to be infected. Current estimates of human infection range from a relatively lower prevalence in countries like the UK (10%), China (10%) and the USA (10–20%) to areas where prevalence can exceed 40% (e.g. parts of continental Europe and South America).

Geoff and Dr Lucy Smyth’s work on lung tissue and Chronic Obstructive Pulmonary Disease; so at Salford University, led them and PhD student Dr Jaro Bajnok to carry out additional tests on the samples to see if any contain Toxoplasma. Working with Professor Dave Singh, clinical consultant at the Medicines Evaluation Unit at Manchester University; so they test 72 tissue samples from patients diagnose with lung cancer and found the parasite in all of them.

Patients had active infections

Further analysis of parasite life cycle stages suggest that 96% of these patients had active infections. Control samples return only a 10% positive match, consistent with the national average. Reporting in the Journal the European Respiratory Journal (Open Research), the team conduct diagnostic tests using five Toxoplasma specific PCR markers and specific immunohisto chemistry demonstrate that the infection was present in lung biopsy

Gondii is capable of infecting virtually all warm blood animals, and is commonly acquire by consuming raw meat or infect water or soil or handling cat litter. It can also be transmit from mother to unborn baby and induce miscarriage. The Manchester team is now planning a much larger study of samples from a broad range of cancer centers. They need to find out why the parasite is so active in these patients. It may be age relate because these are people with lung cancer but that is clearly not the whole story.

Our advice to clinicians at this stage is ‘be aware of the presence of this parasite; so do test for it because it may or may not interfere with any treatment regime. The same team at Salford, UK found a link between incorrectly functioning cellular pumping mechanism in Cystic Fibrosis patients and Toxoplasma Gondii, report in Proceedings of the National Academy of Sciences.