This is a real-world medical entrance exam question, please give the true answer based on the question and selection. Topic name: None, Subject name: Microbiology
All of the following tumours are associated with organisms, EXCEPT: 
Select and explain. 
A. Gastric carcinoma, B. Hepatocellular carcinoma, C. Nasopharyngeal carcinoma, D. Non-small cell lung carcinoma
D: Non-small cell lung carcinoma
Answer: D: Non-small cell lung carcinoma 
Explanation: Cigarette smoking causes 85-90% of cases of non-small cell lung carcinoma. It's etiology is not associated with any organisms. Ceain human malignancies are associated with viruses. Examples include, Burkitt's lymphoma and nasopharyngeal carcinoma (Epstein-Barr virus) Hepatocellular carcinoma (hepatitis viruses) Cervical cancer T cell leukemia (retroviruses) Gastric adenocarcinoma (H pylori) Ref: Morin P.J., Trent J.M., Collins F.S., Vogelstein B. (2012). Chapter 83. Cancer Genetics. In D.L. Longo, A.S. Fauci, D.L. Kasper, S.L. Hauser, J.L. Jameson, J. Loscalzo (Eds), Harrison's Principles of Internal Medicine, 18e.