Figure 1.
High ERCC1 Expression Correlates with Cisplatin Resistance in NSCLC Cells
(A) The expression of ERCC1 in NSCLC cells was analyzed by western blotting. β-Actin was used as an inner control. (B) IC50 values of cisplatin for NSCLC cells. (C) Representative immunohistochemical staining examples of ERCC1 protein expression in cisplatin-resistant NSCLC tissues and cisplatin-sensitive NSCLC tissues (scale bar, 50 μm). The lung cancer tissue sections were quantitatively scored according to the percentage of positive cells and staining intensity as described in Materials and Methods. The percentage and intensity scores were multiplied to obtain a total score (range, 0–12), and the tumors were finally determined as follows: negative (−), score 0; lower expression (+), score ≤4; moderate expression (++), score 5–8; and high expression (+++), score ≥9. (D) ERCC1 expression scores in cisplatin-resistant NSCLC tissues and cisplatin-sensitive NSCLC tissues. (E) Kaplan-Meier overall survival (OS) curves (http://kmplot.com/analysis/) of lung cancer patients administered chemotherapy relative to different expression levels of ERCC1. ∗p < 0.05.