The Lung Microbiota and Lung Cancer: A Growing Relationship

Abstract

The lung is home to a dynamic microbial population crucial to modulating immune balance. Interest in the role of the lung microbiota in disease pathogenesis and treatment has exponentially increased. In lung cancer, early studies suggested an important role of dysbiosis in tumor initiation and progression. These results have helped accelerate research into the lung microbiota as a potential diagnostic marker and therapeutic target. Microbiota signatures could represent diagnostic biomarkers of early-stage disease. Lung microbiota research is in its infancy with a limited number of studies and only single-center studies with a significant methodological variation. Large, multicenter longitudinal studies are needed to establish the clinical potential of this exciting field.

Diallyl trisulfide inhibits 4-(methylnitrosamino)-1-(3-pyridyl)-1-butanone-induced lung cancer via modulating gut microbiota and the PPARγ/NF-κB pathway

“…32 The lung microbiome, in particular, has shown promise as a diagnostic marker and a therapeutic target for lung cancer, especially in the early stages of Food & Function Paper cancers. 33,34 Gut microbiome characteristics have also been explored as potential markers for predicting early lung cancer. 35 In summary, disturbances in the gut microbiome can promote lung cancer progression through various mechanisms, making the gut microbiome a potential diagnostic marker and therapeutic target for lung cancer.…”

Bacterial Interactions Affecting Chemotherapy Effectiveness

“…While balanced bacterial interactions are necessary for immune system drug interactions 7 , some microbial interactions may also undermine chemotherapy treatment and thus contribute to chemotherapy resistance or failure. Examples include metabolising drugs before they can be effective, as seen in Mycoplasma with gemcitabine 5,9,16 ; acting as carcinogens as with Fusobacterium nucleatum and oxaliplatin 18,20,25,26 ; and producing toxins with side effects so severe that they are intolerable for the patient such as with β-glucuronase with irinotecan 27,28,30,31 . Effects vary even between strains of the same species of bacteria.…”

“…Higher rates of bacterial infections in cancerous tumours 7,9,16 suggest either a causal relationship as a carcinogen 20,21 , an increased attraction of bacteria to the tumour micro-environment 6,11,16,18 , or both; there is no consensus as of yet 5 .…”

“…Gemcitabine has been found to be metabolised into an inactive form at solid tumour sites by a long form cytidine deaminase enzyme produced by Mycoplasma, a gammaproteobacteria, which renders the treatment less effective or ineffective 5,9,16,17 . Higher Mycoplasma infection rates in late-stage cancerous tumour samples compared to benign tissue infections were found in 76% of cancerous pancreatic cells compared to 15% of healthy pancreatic tissue samples 9 ; 100% of surgically removed lung tissue was also found to be infected 16 . A higher ratio of Mycoplasma infection was found in stage 3-4 gastric cancer samples compared to stage 1-2 gastric cancer samples 7 .…”

The Complex Role of the Microbiome in Non-Small Cell Lung Cancer Development and Progression

“…While the involvement of the gut microbiome in treatment response has been well documented in the development and immunotherapy of lung cancer [30,31], recent studies suggest that the microbiota in the lungs also play a role in lung cancer development [32][33][34][35]. Microorganisms such as bacteria, viruses, and fungi have emerged as pivotal players in the complex interplay of factors contributing to cancer initiation, promotion, and progression [36] and lung cancer development [32,33]. Studies have reported that the levels of Actinomyces, Veillonella, Streptococcus, Megasphaera, and Mycobacterium were more abundant in patients with lung cancer compared with healthy individuals [37][38][39].…”