Background The tumor microenvironment (TME) is a critical player in tumor progression, metastasis and therapy outcomes. Tumor-associated macrophages (TAMs) are a well-recognized core element of the TME and generally characterized as M2-like macrophages. TAMs are believed to contribute to tumor progression, but the mechanism behind this remains unclear. We aimed to investigate the clinical, angiogenic, and lymphangiogenic significance of TAMs in non-small cell lung cancer (NSCLC). Methods Utilizing combined immunohistochemistry and digital image analysis, we assessed CD68, CD163, VEGF-A, and VEGF-C expression in 349 patients with NSCLC. Subsequently, the potential association between M2 TAMs and angiogenic VEGF-A and/or lymphangiogenic VEGF-C was evaluated for its prognostic value. Furthermore, the effects of M2 TAMs on angiogenesis and lymphangiogenesis were explored via an in vitro co-culture system. Results CD68 and CD163 expression were found to directly correlate with VEGF-A and/or VEGF-C expression (all p < 0.001). Furthermore, elevated M2 ratio (CD163+/CD68+) was significantly associated with poor overall survival (p = 0.023). Dual expression of M2 ratiohigh and VEGF-Chigh (M2 ratiohighVEGF-Chigh) was correlated with worse overall survival (p = 0.033). Multivariate analysis revealed that M2 ratiohigh [HR (95% CI) = 1.53 (1.01–2.33), p = 0.046] and combined M2 ratiohighVEGF-Chigh expression [HR (95% CI) = 2.01 (1.28–3.16), p = 0.003] were independent predictors of poor overall survival. Notably, we confirmed that M2 macrophages significantly enhanced the protein and mRNA expression of both VEGF-A and VEGF-C, while M1 macrophages induced only mRNA expression of VEGF-A in A549 cells. Conclusions This study suggests that TAMs are significantly associated with angiogenesis and lymphangiogenesis, contributing to the progression of NSCLC. Furthermore, elevated M2 ratio, similar to combined high M2 ratio and high VEGF-C expression, is a strong indicator of poor prognosis in patients with NSCLC, providing insight for future TAM-based immunotherapy strategies.

Summary Synaptonemal complex protein 3 (SCP3) is a marker for cell transformation that has prognostic significance in various cancers. However, the prognostic significance of SCP3 has not been studied in non-small cell lung cancer (NSCLC). To investigate the potential correlation between SCP3 and various clinicopathologic parameters, we assessed the expression of SCP3 in archival tumor tissues from 258 NSCLC patients by immunohistochemical staining. By immunofluorescence, SCP3 was detected in both the cytoplasmic and nuclear fractions of NCI-H1299 cell. In tumor samples, SCP3 is detected as cytoplasmic expression pattern and observed in 50 (19.4%) clinical samples by immunohistochemical staining. SCP3 expression was correlated with T status (P=0.008), lymph node metastasis (P=0.010), tumor types (P=0.019) and pleural invasion (P=0.005). In multivariate analysis of patients with early stage disease, increased SCP3 expression predicted worse overall survival in early stage (stage I–II) with pT1 status (P=0.041). These results suggest that positive SCP3 expression is a portent of poor outcome, and may be a potential biomarker in the early stages of the NSCLC for survival and may provide clues in the identification of patients for adjuvant therapy.

Activation of numerous pathways has been documented in non-small cell lung cancer (NSCLC). Epidermal growth factor receptor (EGFR) has emerged as a common therapeutic target. The mitogen-activated protein kinase (MAPK) and AKT signaling pathways are downstream of EGFR and deregulated via genetic and epigenetic mechanisms in many human cancers. We evaluated selected markers in the EGFR pathway with reference to outcome. Tissues from 220 cases of NSCLC patients presented in a tissue microarray were assayed with immunohistochemistry for phosphorylated AKT, phosphorylated MAPK, phosphorylated mTOR, and EGFR and then quantified by automated image analysis. Individually, the biomarkers did not predict. Combined as ratios, p-mTOR/p-AKT, and p-MAPK/EGFR function as prognostic markers of survival (p=0.008 and p=0.029, respectively), however, no significance was found after adjustment (p=0.221, p=0.103). The sum of these ratios demonstrates a stronger correlation with survival (p<0.001) and remained statistically significant after adjustment (p=0.026). The algebraic combination of biomarkers offer the capacity to understand factors that predict outcome better than current approaches of evaluating biomarkers individually or in pairs. Our results show the sum of p-mTOR/p-AKT and p-MAPK/EGFR is a potential predictive marker of survival in NSCLC patients.