br Fig Expression of IRF protein in the
Fig. 4. Expression of IRF5 protein in the tissues of non-small cell lung cancer (NSCLC). Cancer tissues (CT) and para-carcinoma tissues (PCT) derived from the NSCLC patients were analysed for IRF5 protein levels by Western blotting and relative quantitative analysis based on the grey values of the blotting. Based on the grey values, the IRF5 protein levels in the PCT and CT were analysed, which were used to analyse the relationship with stages of the disease, survival rates, and ages of the patients. (A) Expression levels of IRF5 protein in the PCT and CT of the NSCLC patients. (B) IRF5 protein levels in the CT of the NSCLC patients at diﬀerent histological types. (C) IRF5 protein levels in the CT of the NSCLC patients at diﬀerent stages. (D) Survival rates of the total NSCLC patients with high or low levels of IRF5 protein. The average IRF5 level in the CT of the NSCLC patients, 0.5430, was set as the cutting edge: IRF5high (IRF5 levels > 0.5430) and IRF5low (IRF5 levels < 0.5430). (E) IRF5 protein levels in the CT and PCT of the NSCLC patients in the diﬀerent age groups. (F) Expression levels of IRF5 protein in the CT of the NSCLC patients in the diﬀerent age groups. (G) Relationship between IRF5 protein levels in the CT and the NSCLC stage in the diﬀerent age groups. AD, adeno-carcinoma; SQ, squamous cell carcinoma; ES, early stage; PS, progressive stage.
was shown to significantly inhibit its own mRNA expression . High expression of IL-10 in the sera of the NSCLC patients was associated with lower survival rates . Overall, our results indicate that the IRF5 expression in the WBCs and the levels of its downstream cytokines, IL-10 in the WBCs and IL-6 and IP-10 in the plasma, could be used as candidate biomarkers of the possible presence of NSCLC, which is in agreement with a previous report that IL-6, IL-10, and IP-10 have a diagnostic value in lung cancer [44,45]. However, since IRF5 is an
upstream regulator of IL-6, IL-10, and IP-10, IRF5 expression could be a more important diagnostic biomarker for early stage NSCLC.
In the present study, higher IRF5 levels were detected in the WBCs of the NSCLC patients than in those of the healthy controls, and in early stage NSCLC than in progressive NSCLC, suggesting that IRF5 expres-sion in the peripheral blood Talaporfin sodium (ME2906) could be used as a diagnostic bio-marker of NSCLC in general and early stage NSCLC in particular. However, it should be noted that patients with other diseases such as
influenza virus infection, community-acquired pneumonia, systemic lupus erythematosus (SLE), and hepatitis C may also have high IRF5 expression in their peripheral blood cells [46–49]. Patients infected with influenza virus often have a high fever, body aches, and con-junctivitis, with influenza virus particles detected in the mucosal epi-thelial cells in nasal washes. In SLE patients, butterfly-like erythema often appears on the cheeks, and abnormal clinical manifestations can occur in the kidneys, lungs, central nervous system, and/or heart with disease progression. In addition, positive anti ds-DNA antibody in the serum is conducive to SLE diagnosis. In patients with community-ac-quired pneumonia, elevated IRF5 levels could be significantly reduced by eﬀective pathogen-targeting therapy, as reported by our group . Additionally, elevated IRF5 in patients with HCV-1 is reduced after eﬀective antiviral therapy . In contrast, IRF5 upregulation in the peripheral blood cells of NSCLC patients persists, which could be pri-marily from the response of innate immune cells to tumour cells and should not be aﬀected by pathogen-targeting diagnostic treatment be-fore definitive diagnosis. Therefore, increased IRF5 expression in per-ipheral blood cells could be used as a biomarker of early stage NSCLC after the exclusion of the other diseases associated with IRF5 upregu-lation. In particular, IRF5 monitoring may improve diagnostic accuracy when pulmonary nodules are detected by low-dose computed tomo-graphy (LDCT), because only 60% of the observed nodules larger than 4 mm appear to be malignant . In such cases, the cancerous nature of the nodules should be confirmed based on lung cancer-associated molecular changes. Currently, a panel of seven tumour-associated an-tigens, including p53, NY-ESO-1, CAGE, GBU4-5, SOX2, HuD, and MAGE A4, is used to detect respective autoantibodies indicative of anti-cancer humoral immune response, with an overall specificity of 91% in NSCLC cases . The measurement of IRF5 expression in peripheral blood cells could be complementary to this assay and improve its di-agnostic specificity for early stage NSCLC. In addition, bronchial gene expression biomarkers could be added to provide a comprehensive lung cancer risk assessment .