Background: Activating mutations of the epidermal growth factor receptor (
EGFR) gene are known to drive a proportion of non-small-cell lung cancers. Identification of lung cancers harbouring such mutations can lead to effective treatment using one of the agents that targets and
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Background: Activating mutations of the epidermal growth factor receptor (
EGFR) gene are known to drive a proportion of non-small-cell lung cancers. Identification of lung cancers harbouring such mutations can lead to effective treatment using one of the agents that targets and blocks
EGFR-mediated signalling.
Methods: All specimens received at the BC Cancer Agency (Vancouver) for
EGFR testing were prospectively identified and catalogued, together with clinical information and
EGFR status, over a 14-month period.
Results: Specimens from 586 patients were received for
EGFR testing, and
EGFR status was reported for 509 patients. No relationship between specimen type or site of origin and
EGFR test failure rate was identified. Concurrent immunohistochemical (
IHC) status for thyroid transcription factor 1 (
TTF1) was available for 309 patients. The negative predictive value of
TTF1-negative status by
IHC was 94.2% for predicting negative
EGFR status.
Conclusions: In patients with limited tissue available for testing, a surrogate for
EGFR status would aid in timely management. Immunohistochemistry for
TTF1 is readily available and correlates highly with
EGFR status. In conjunction with genetic assays,
TTF1 could be used to optimize an
EGFR testing strategy.
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