Purpose To evaluate the prognostic and predictive significance of plasma levels of the epidermal growth factor receptor (EGFR) ligands, transforming growth factor α (TGF-α) and amphiregulin, in patients with non–small-cell lung cancer (NSCLC) enrolled in NCIC Clinical Trials Group BR.21 comparing erlotinib with placebo. Patients and Methods TGF-α and amphiregulin were assessed retrospectively by enzyme-linked immunosorbent assay from available prospectively collected baseline plasma samples in 565 of 731 BR.21 patients. Cutoff points were determined for both amphiregulin (low, < 10 pg/mL; high, ≥ 10 pg/mL) and TGF-α (low, ≤ 12 pg/mL; high, > 12 pg/mL) using a graphical method. Cox regression models were used to correlate biomarker data and baseline characteristics with outcomes including overall (OS) and progression-free survival (PFS). Results High TGF-α and amphiregulin were associated with poorer performance status (P = .06 and P < .0001, respectively) and no prior platinum therapy (P = .06 and P = .02, respectively). High amphiregulin was also associated with anemia (P = .001), increased lactate dehydrogenase (P = .03), ever-smokers (P = .04), and non-Asian ethnicity (P = .001). Patients on the placebo arm with high amphiregulin had poorer OS than patients with low amphiregulin (hazard ratio [HR] = 1.88; 95% CI, 1.34 to 2.64; P = .0002), which remained significant in multivariate analysis. Amphiregulin levels did not predict for benefit from erlotinib (interaction P = .87). Conversely, TGF-α levels did not have prognostic significance, but high TGF-α predicted lack of benefit from erlotinib compared with low TGF-α (TGF-α low, OS HR = 0.66; 95% CI, 0.54 to 0.81; P < .0001; high, OS HR = 1.32; 95% CI, 0.73 to 2.39; P = .36; interaction P = .04). Conclusion High baseline amphiregulin is a poor prognostic factor, whereas high baseline TGF-α predicts for lack of benefit from erlotinib in advanced NSCLC.
Serum levels of transforming growth factor-α in patients after partial hepatectomy as determined with an enzyme-linked immunosorbent assay
