Evaluation of EGFR protein expression by immunohistochemistry using H-score and the magnification rule: re-analysis of the SATURN study

Lung Cancer. 2013 Nov;82(2):231-7. doi: 10.1016/j.lungcan.2013.07.016. Epub 2013 Aug 7.


Introduction: The phase III SATURN study demonstrated that first-line maintenance erlotinib extended progression-free survival (PFS) and overall survival (OS) versus placebo in patients with advanced non-small cell lung cancer (NSCLC). Analysis of epidermal growth factor receptor (EGFR) expression by immunohistochemistry (IHC) found no significant interaction between EGFR IHC status and PFS (p = 0.63) or OS (p = 0.52). The FLEX study of first-line cetuximab plus chemotherapy demonstrated that EGFR IHC expression was predictive of improved OS with cetuximab when assessed by H-score with a magnification rule. This novel method was used to reassess samples from SATURN.

Methods: The H-score method assigned a score of 0-300 to each patient, based on the percentage of cells stained at different intensities viewed at various magnifications. The discriminatory threshold was set at 200, per the FLEX study, and existing samples were re-read and classed as low (H-score < 200) or high (≥200) EGFR expression. PFS and OS were re-analyzed based on these new classifications.

Results: In the overall and EGFR wild-type populations, erlotinib provided a consistent survival benefit versus placebo. Hazard ratios (HRs) in the overall population were similar between EGFR IHC-positive and -negative patients for median PFS (HR 0.68 [95% confidence interval (CI) 0.53-0.86] and 0.76 [95% CI 0.62-0.93], respectively) and OS (HR 0.80 [95% CI 0.62-1.05] and 0.80 [95% CI 0.64-1.01] for IHC-positive and IHC-negative, respectively). In the EGFR wild-type population, HRs were again similar between EGFR IHC-positive and -negative subpopulations for PFS (HR 0.69 [95% CI 0.51-0.95] and 0.84 [95% CI 0.63-1.12], respectively) and OS (HR 0.78 [95% CI 0.55-1.10] and 0.76 [95% CI 0.55-1.05], respectively).

Conclusions: These data suggest that EGFR IHC does not have value as a marker to predict erlotinib benefit in the first-line maintenance setting for advanced NSCLC.

Keywords: Biomarkers; Epidermal growth factor receptor; Erlotinib; Immunohistochemistry; Maintenance; Non-small cell lung cancer.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adult
  • Aged
  • Aged, 80 and over
  • Antineoplastic Combined Chemotherapy Protocols / therapeutic use
  • Carcinoma, Non-Small-Cell Lung / drug therapy
  • Carcinoma, Non-Small-Cell Lung / metabolism*
  • Carcinoma, Non-Small-Cell Lung / mortality
  • Carcinoma, Non-Small-Cell Lung / pathology
  • ErbB Receptors / antagonists & inhibitors
  • ErbB Receptors / metabolism*
  • Female
  • Gene Expression
  • Humans
  • Immunohistochemistry
  • Lung Neoplasms / drug therapy
  • Lung Neoplasms / metabolism*
  • Lung Neoplasms / mortality
  • Lung Neoplasms / pathology
  • Male
  • Middle Aged
  • Neoplasm Staging
  • Protein Kinase Inhibitors / pharmacology
  • Protein Kinase Inhibitors / therapeutic use
  • Risk Factors


  • Protein Kinase Inhibitors
  • ErbB Receptors