BACKGROUNDPatients 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.

METHODSGene 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.

RESULTSWe 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.

CONCLUSIONSOur 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.

Adult ; Aged ; Carcinoma, Non-Small-Cell Lung ; metabolism ; mortality ; pathology ; Claudin-1 ; analysis ; genetics ; Female ; Humans ; Immunohistochemistry ; Insulin-Like Growth Factor II ; analysis ; genetics ; Lung Neoplasms ; metabolism ; mortality ; pathology ; Male ; Middle Aged ; Neoplasm Staging ; Prognosis

OBJECTIVEThis study aimed to explore the expression of tumor-derived colony-stimulating factor 1 (CSF1), its prognostic significance and underlying related mechanisms in resected lung adenocarcinoma (ADC).

METHODSImmunohistochemistry and tissue microarray were used to detect the expression of CSF1, epidermal growth factor receptor (EGFR), and CD68 in 266 patients with lung adenocarcinoma treated in our department between 2004 and 2008.

RESULTSIn the 266 ADC cases, the positive rates of expression of CSF1, EGFR and CD68 proteins were 56.4%, 42.1% and 81.2%, respectively. The expression level of CSF1 was positively correlated with TNM stage, number of involved nodal stations, tumor recurrence and EGFR expression (P<0.05). Univariate analysis indicated that TNM stage, number of involved lymph nodes, number of involved nodal stations, CSF1 expression, the combination of CSF1/EGFR and co-expression of CSF1/CD68/EGFR were statistically significant for prognosis (P<0.05). The results of multivariate analysis showed that TNM stage, co-expression of CSF1/EGFR and CSF1/CD68/EGFR were significant and independent risk factors for survival (P<0.05). Correlational analysis showed that expression of CSF1 and EGFR in the tumors was positively correlated to the degree of infiltration of interstitial tumor-associated macrophages (TAMs) (respectively; P<0.05).

CONCLUSIONSThe expression of CSF1 indicates a poor prognosis in postoperative lung adenocarcinoma. Co-expression of CSF1 and EGFR may be a valuable independent prognostic predictor, and its mechanism is probably involved in the interaction of cancer cells and TAMs in the progression of lung adenocarcinoma.

Adenocarcinoma ; diagnosis ; metabolism ; Disease Progression ; Humans ; Immunohistochemistry ; Lung Neoplasms ; diagnosis ; metabolism ; Macrophage Colony-Stimulating Factor ; metabolism ; Macrophages ; Prognosis