Lung cancer and pulmonary tuberculosis: key features of molecular mechanisms of concomitant disease

Lung cancer and pulmonary tuberculosis have long been significant problems for global health, occupying leading positions in terms of morbidity and mortality in both developed and developing countries. Numerous clinical and experimental studies have allowed to get knowledge of the mechanisms of development of these pathological processes individually, the impact of diseases on the macroorganism, and various options of treatment. According to population studies, the interaction between these two processes is undeniable – both active tuberculosis and post-tuberculosis changes are equally risk factors for the development of neoplastic processes, and malignant tumors create favorable conditions and predispositions for the development of mycobacterial infection. However, the mechanisms of interaction between these two diseases in concomitant cases remain opened and insufficiently studied. This literature review provides a detailed description of the variants of lung cancer and pulmonary tuberculosis combinations, the pathophysiological basis of the interaction between infectious and neoplastic processes: modulation of the immune response by M. tuberculosis and lung tumor; oncogenic signaling pathways activated by tuberculosis infection; mechanisms of epithelial-mesenchymal transition in post-tuberculosis scar changes and its role in the formation of so-called "scarcinoma"; the relationship between tumor-mediated and tuberculosis-associated immunosuppression; the role of the PD-1: PD-L signaling pathway, and the influence of modern types of anti-tumor immunotherapy on the course of these pathological processes. The final part of the review presents our own data from experimental studies on the combination of cancer and tuberculosis in a laboratory model, identifying promising directions for further research on this issue.