Figure 5.

 Relationship between pemetrexed sensitivity and the expression levels of thymidylate synthase (TS), reduced folate carrier (RFC)‐1, and folylpoly‐gamma‐glutamate synthetase (FPGS) genes in non‐small‐cell lung cancer (NSCLC) cell lines. TS expression and pemetrexed sensitivity are strongly correlated in all NSCLC cell lines investigated (n = 11, r = 0.624, P < 0.005), but no significant correlation was observed between the expression levels of the other genes investigated and pemetrexed sensitivity. Each IC₅₀ value is the mean of three independent sensitivity tests performed in quadruplicate. Expression levels were normalized to GAPDH expression. The statistical significance of each correlation was determined by Spearman’s correlation test. Closed square (), NSCLC cells.