Tumours are characterised by an ability to avoid immune destruction and the presence of cancer-associated inflammation. Better understanding of the link between lung cancer and such inflammation is vital for early detection and personalized treatment. Thus, we examined the mRNA expression of interleukins IL-1β, IL-6, IL-17 and miR-9, miR-122 as potential useful biomarkers of NSCLC. Tumour tissues, non-cancerous tissue and blood samples were collected from 39 patients with primary NSCLC undergoing surgical treatment. The selected RNA was isolated from tissue samples and selected miRNAs from peripheral blood exosomes. This RNA was transcribed to cDNA and quantified using RT-qPCR. Significantly higher expression of the selected interleukins was observed in non-cancerous than tumour tissue, and IL-6 was significantly higher in the tumour tissue of patients with a history of ≤ 40 pack-years (PYs) (2.197, IQR: 0.821–4.415) than in those with > 40 PYs (0.461, IQR: 0.372–0.741; p = 0.037). It is clear that inflammatory processes play a role in NSCLC, as indicated by the upregulation of IL-1β and IL-6 in tumour and adjacent tissue, and that smoking has a strong influence on inflammation in tumourigenesis, demonstrated by the upregulation of IL-6 in tumour samples among patients with ≤ 40 PYs compared to > 40 PYs.

In lung cancer patients, two complementary abnormalities were found that can cause disruption of the mitochondrial network: increased fusion and impaired fission, manifested by reduced levels of FIS1, a mitochondrial division regulator, and increased expression of MFN1, a mitochondrial fusion mediator. Immunoexpression studies of MFN1 and FIS1 proteins were performed in serum samples obtained from 47 patients with non-small cell lung cancer (NSCLC) and 21 controls. In the NSCLC patients, the immunoexpression of the MFN1 protein was significantly higher, and the FIS1 protein level was significantly lower than in the control group (p < 0.01; p < 0.001; UMW test). Patients with early, operable lung cancer had significantly lower levels of MFN1 immunoexpression compared to patients with advanced, metastatic lung cancer (p < 0.05; UMW test). This suggests that early stages of the disease are characterized by greater fragmentation of damaged mitochondria and apoptosis. In contrast, lower FIS1 protein levels were associated with a worse prognosis. Increased mitochondrial fusion in the blood of lung cancer patients may suggest an increase in protective and repair mechanisms. This opens up questions about why these mechanisms fail in the context of existing advanced cancer disease and is a starting point for further research into why protective mechanisms fail in lung cancer patients.

Two suppressor genes which often undergo epigenetic silencing during the early stages of lung carcinogenesis are those encoding retinoic acid receptor-β (RARβ) and Fhit protein (FHIT). RARβ expression is regulated by miRNA-34a and miRNA-141, and FHIT expression by miRNA-143 and miRNA-217. The aim of the study was to assess how selected miRNAs regulate the expression of their targeted genes in bronchoalveolar lavage fluid (BALf), obtained from patients with SCC of the lung. It also examines the relationship between the genetic findings and the clinical and pathomorphological features of the tumor. A total of 50 BALf samples were taken: 25 from patients with SCC and 25 from healthy donors. The expression (RQ) of the selected genes was analyzed by qPCR, as well as the miRNA level, with a particular emphasis on the relationship between the expression of the genes themselves and their corresponding miRNAs; in addition, the expression of the genes and miRNAs were compared with the pathomorphological features of the tumor and the clinical features of patients. Analysis of the RQ values showed downregulation of RARß, FHIT and miRNA-34a and increased expression of miRNA-141, miRNA-143 and miRNA-217 in all BALf samples (P > 0.05). No correlation was found between the expression of the selected genes and corresponding miRNAs, history of smoking, cancer stage, age and sex of the patients. The presence of the selected genes and miRNAs in BALf material does not seem to have diagnostic potential in patients with SCC; however, the results should be verified on a larger group of patients.