Claudin-1 correlates with poor prognosis in lung adenocarcinoma.

BACKGROUND: This study was conducted to investigate the clinical significance of claudin-1 (CLDN1) expression in patients with lung adenocarcinoma. METHODS: We examined CLDN1 protein expression by immunohistochemistry in a tissue microarray from 258 patients with lung adenocarcinoma. We investigated messenger ribonucleic acid (mRNA) expression in H358 (formerly bronchioloalveolar carcinoma) and lung adenocarcinoma cell lines (A549) by real-time reverse transcriptase-polymerase chain reaction. RESULTS: Multivariate analysis showed that prognostic factors for lung adenocarcinoma were histologic type, CLDN1, T stage and N stage. Patients with positive CLDN1 expression had a poorer prognosis than patients with negative CLDN1 expression. CLDN1 expression was correlated with Ras and epidermal growth factor receptor (EGFR) expression. Patients with positive expressions of both CLDN1 and Ras/EGFR had a poorer prognosis than patients with CLDN1 (+) Ras/EGFR(-) or CLDN1 (-) Ras/EGFR(+) and patients with negative expressions of both CLDN1 and Ras/EGFR. CLDN1 mRNA expression was lower in the H358 compared with the lung adenocarcinoma cell line (A549). CONCLUSION: The combination of CLDN1 and Ras/EGFR is a valuable independent prognostic predictor for lung adenocarcinoma.

Significance of interstitial tumor-associated macrophages in the progression of lung adenocarcinoma.

Stepwise progression from adenocarcinoma in situ (AIS) and minimally invasive adenocarcinoma (MIA) to lepidic predominant adenocarcinoma (LPA) was proposed by various scholars. Interstitial tumor-associated macrophages (TAMs) and various potential chemokines involved in the progression from AIS/MIA to LPA were hypothesized. In the present study, immunohistochemistry or immunofluorescent double staining was used to detect the expression of the TAMs marker cluster of differentiation (CD) 68, tumor-derived colony-stimulating factor (CSF)-1, interleukin (IL)-6, matrix metalloproteinase (MMP)-2, E-cadherin and Snail in lung adenocarcinoma specimens, including AIS/MIA, LPA and other types. It was observed that infiltrating TAMs were negatively associated with the prognosis of patients, and that the infiltration degree of interstitial TAMs was higher in LPA than that in AIS/MIA. In addition, E-cadherin, Snail and MMP-2 expression were significantly correlated with the infiltration degree of TAMs. Survival analysis revealed that co-expression of CD68, CSF-1 and IL-6 was an independent prognostic factor. Stratified analysis demonstrated that, in AIS/MIA patients, there was a statistically significant difference between the number of TAMs (TAMs ≤25 and TAMs >25) in the CD68+CSF-1+IL-6+ group compared with other groups (including CD68+CSF-1-IL-6-, CD68+CSF-1+IL-6-, CD68+CSF-1-IL-6+ and CD68- groups). By contrast, in patients with TAMs >25 and in patients with positive CD68, CSF-1 and IL-6 expression, the survival rates were not significantly different between AIS/MIA and LPA. These results suggested that co-expression of TAMs marker CD68, CSF-1 and IL-6 may be a valuable independent prognostic predictor in lung adenocarcinoma. TAMs may facilitate AIS/MIA progression to LPA, which may be closely associated with the induction of the epithelial-mesenchymal transition.

Interstitial tumor-associated macrophages combined with tumor-derived colony-stimulating factor-1 and interleukin-6, a novel prognostic biomarker in non-small cell lung cancer.

OBJECTIVES: Recent experimental evidence has indicated that interstitial tumor-associated macrophages (TAMs), tumor-derived macrophage colony-stimulating factor (also known as CSF-1), and interleukin-6 (IL-6) interact in the pathogenesis of malignant epithelial tumors, including lung cancer. The present study aimed to explore their relationship and prognostic significance in surgically resected non-small cell lung cancer (NSCLC). METHODS: Tissue microarray and immunohistochemistry were used to detect the expression of CSF-1, IL-6, and CD68-positive TAMs in 417 patients with NSCLC undergoing complete pulmonary resection from 2003 to 2008. Their correlations and clinicopathologic data were analyzed using chi-square testing. Their prognostic values were evaluated by univariate Kaplan-Meier survival analysis and multivariate Cox proportional hazard model analysis. RESULTS: The expression of CSF-1 and IL-6 in NSCLC correlated positively with the infiltration degree of TAMs in the tumor stroma (r=0.184 and r=0.196, respectively; P<.001). The expression of both CSF-1 and IL-6 was statistically significant for survival (P<.001). Nevertheless, no such relationship was observed for CD68 in the tumor stroma (P>.05). When CSF-1 and/or IL-6 and CD68 were taken into consideration together, the result became statistically significant. Multivariate analysis showed that co-expression of CD68, CSF-1, and IL-6 remained the most significant and independent prognostic factor for survival (P<.05) but not the combinations of CSF-1 and IL-6, CD68 and CSF-1, or CD68 and IL-6 (P>.05). The 5-year survival rate in the CD68-negative and CSF-1- and IL-6-positive group was better than the rate in the CD68, CSF-1-, and IL-6-positive group (P<.05). CONCLUSIONS: The combination of CD68 plus TAMs, CSF-1, and IL-6 is very likely to be a valuable independent predictor of survival in patients with NSCLC. Perhaps co-expression of CSF-1 and IL-6 induces interstitial TAMs to shift toward the tumor-promoting phenotype.

Expressions of CLDN1 and insulin-like growth factor 2 are associated with poor prognosis in stage N2 non-small cell lung cancer.

BACKGROUND: Patients with single station mediastinal lymph node (N2) non-small cell lung cancer (NSCLC) have a better prognosis than those with multilevel N2. The molecular factors which are involved in disease progression remain largely unknown. The purpose of this study was to investigate gene expression differences between single station and multilevel N2 NSCLC and to identify the crucial molecular factors which are associated with progress and prognosis of stage N2 NSCLC. METHODS: Gene expression analysis was performed using Agilent 4×44K Whole Human Genome Oligo Microarray on 10 freshfrozen lymph node tissue samples from single station N2 and paired multilevel N2 NSCLC patients. Real-time reverse transcription (RT)-PCR was used to validate the differential expression of 14 genes selected by cDNA microarray of which four were confirmed. Immunohistochemical staining for these validated genes was performed on formalin-fixed, paraffinembedded tissue samples from 130 cases of stage N2 NSCLC arranged in a high-density tissue microarray. RESULTS: We identified a 14 gene expression signature by comparative analysis of gene expression. Expression of these genes strongly differed between single station and multilevel N2 NSCLC. Four genes (ADAM28, MUC4, CLDN1, and IGF2) correlated with the results of microarray and real-time RT-PCR analysis for the gene-expression data in samples from 56 NSCLC patients. Immunohistochemical staining for these genes in samples from 130 cases of stage N2 NSCLC demonstrated the expression of IGF2 and CLDN1 was negatively correlated with overall survival of stage N2 NSCLC. CONCLUSIONS: Our results suggest that the expression of CLDN1 and IGF2 indicate a poor prognosis in stage N2 NSCLC. Further, CLDN1 and IGF2 may provide potential targeting opportunities in future therapies.