EGFR Mutation Testing

Performing Lab:

UCSF Clinical Cancer Genomics Lab

CPT Code:

81235, 88381

Specimen Type: Formalin-fixed, paraffin-embedded tissue. Tissue block or unstained slides. If sending unstained slides, we require five (5) 10-micron tissue sections on uncharged glass slides. One adjacent H&E stained slide should be included. Cytology smears may also be used for testing if there is sufficient tumor present. Contact the laboratory at 415.502.3252 or [email protected] if testing on a cytology smear is desired.
Methodology: Sanger sequencing
Turnaround Time: 7-14 days

TEST INDICATIONS:

EGFR mutations are commonly seen in non-small cell carcinomas of the lung, usually in adenocarcinomas, but much less frequently in adenosquamous carcinoma as well. They are extremely rare in squamous cell carcinoma. Some mutations in EGFR, such as the L858R mutation and exon 19 deletion, have been shown to be predictive of response to EGFR-directed tyrosine kinase inhibitors (TKIs) in patients with non-small cell lung cancer. Other EGFR mutations, such as T790M and exon 20 insertion, are associated with resistance to EGFR TKIs.

EGFR mutation testing is not indicated for EGFR monoclonal antibody therapy in patients with metastatic colorectal carcinoma. For these patients, KRAS mutation testing (with consideration of NRAS and BRAF mutation testing) is recommended.

HOW THE TEST WORKS:

A histologic section of formalin-fixed, paraffin-embedded tissue is examined by a pathologist to identify areas of tumor. DNA is extracted from these areas and regions of EGFR exons 18, 19, 20 and 21 that contain the most common EGFR mutations are captured and sequenced by next generation sequencing.

LIMITATIONS OF THE TEST:

Results of this test should be correlated with the patient’s other clinical and laboratory information. This test is designed to detect point mutations and small insertions and deletions in exons 18 through 21 of EGFR, including the following mutations: exon 19 deletions, exon 20 insertions, L858R, L861Q, S768I, T790M and G719A/S.

This test was validated by the UCSF Clinical Cancer Genomics Laboratory to confirm performance characteristics, in compliance with current guidelines for clinical implementation.

SPECIMEN REQUIREMENTS FOR A SUCCESSFUL TEST:

In general, the tumor should be a minimum of 0.4 cm in size. Blocks selected for EGFR Mutation Testing must contain tumor tissue. Areas of tumor must contain at least 50% tumor cells. The lab can remove adjacent non-tumor tissue, so the entire slide does not need 50% tumor cells, just the area with tumor. Contact the laboratory at 415.502.3252 or [email protected] if the specimen suitability is uncertain. Label slides with pathology case number and block identification.

Specimen rejection criteria include: All required slides not included. Insufficient tumor tissue present on slide as determined by pathologist. Outside slides not labeled or not accompanied by printed copy of test order.

HOW TO ORDER THE TEST:

UCSF Clinicians — this test can be ordered through APeX
Outside Physicians — this test can be ordered using the CCGL Requisition Form

For all specimens, an interpretation of this test by a laboratory physician will automatically be performed and billed for separately.