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EGFRDeletionDraft, not yet medically reviewed

EGFR Exon 19 Deletion (del19): Meaning in Lung Cancer

A group of EGFR mutations most often found in non-small-cell lung cancer and commonly discussed when choosing targeted therapy.

Parent marker: EGFR

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What is EGFR exon 19 deletion or del19?

Exon 19 deletion means genetic material is missing in exon 19 of the EGFR gene. Reports may use del19 or exon 19 del. Record the full variant name for discussion with your doctor.

Source: NCBI / NCI: EGFR exon 19 deletion

Prepare these details for your consultation

  • Copy the full variant name from the report
  • Record sample type and test date
  • Prepare treatment history and recent reports
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Clinical meaning

Changes in exon 19 make the EGFR growth signal continuously active. This group is among the most responsive to EGFR inhibitors, so it is usually the basis for discussing first-line therapy in advanced disease.

How this finding appears in a report

Can be found through a sequencing panel or targeted PCR. Reports need to state the name of the specific variant, not just the positive status.

Tests usually used

When therapy stops working

When therapy stops working, repeat testing usually looks for T790M, MET changes, HER2 amplification, or other pathway changes through re-sequencing.

What needs verification

  • Complete variant name as written in the laboratory report.
  • Examination methods and types of samples used.
  • Examination dates were compared with ongoing therapy.

Marker context: EGFR

A common EGFR mutation (exon 19 deletion, L858R) alters the way systemic therapy is selected in non-small-cell lung cancer. Other groups of mutations, including exon 20 insertions, are generally considered distinct and are often directed to other pathways, including clinical trials.

A negative result does not always mean absent

Test sensitivity differs by sample type and method. Results need to be read together with the pathology report and clinical condition.

Summary

Gen
EGFR
Variant
EGFR exon 19 deletion (del19)
Alteration type
Deletion
Discussed in
Lung Cancer
Updated
2026-09-10

Other names in reports

del19, exon 19 del, E746-A750del

Drugs discussed

Treatment categories

Related guides

Sources

Clinical trials

Studies mentioning marker EGFR

Filtered from public study descriptions. Access status and site readiness remain unverified.

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