Laboratory Test Guide

KRAS Mutations (DNA)

General Information

Lab Name

KRAS Mutations

Lab Code

KRAS

Epic Name

Order using "UW Genetics and Solid Tumor Test Request"

For solid tumors only. Use Heme Single Gene by NGS [HCAPSG] for hematopoietic malignancies.

See tip sheet for more information (internal link).

Description

Please note that KRAS Mutations is intended for solid tumors, for testing related to hematologic malignancies, please order - Heme Single Gene by NGS [HCAPSG]. Consultation with a Director can be requested to determine the appropriate testing. Please contact the laboratory at 206-598-6429 for further questions.

This test detects mutations in exons 2, 3, and 4 of the KRAS gene, which includes codons 12, 13, 59, 61, 117, and 146. Acquired KRAS mutations at these codons are associated with resistance to drugs that target the epidermal growth factor receptor (including cetuximab and panitumumab). KRAS p.G12C mutations in lung canacers have been associated with efficacy of specific inhibitors (e.g. sotorasib). This test can normally detect a heterozygous mutation if it is present in more than about 10% of the cells in the sample.

References

Skoulidis F, et al. Sotorasib for Lung Cancers with KRAS p.G12C Mutation. N Engl J Med. 2021 384(25):2371-2381. PMID: 34096690
Karapetis CS, et al. K-ras mutations and benefit from cetuximab in advanced colorectal cancer. N Engl J Med 2008, 359:1757-65. 18946061
Lièvre A, et al. KRAS mutations as an independent prognostic factor in patients with advanced colorectal cancer treated with cetuximab. J Clin Oncol 2008, 26:374-9. 18202412

Synonyms

cetuximab, colorectal cancer, erbitux, extended RAS, G12C, Gynecological Oncology Pathway, GYNPTH, K-RAS, Ki-Ras, LUMAKRAS, lung, lung cancer, metastatic colon cancer gene testing, NGS, p.G12C, panitumumab, Ras, sotorasib, THOR, THORplex, Vectibix

Components

Code	Name
KRARES	KRAS Result
KRASCH	KRAS Clinical History
KRAINT	KRAS Interpretation
KRAMTH	KRAS Methods
KRASDI	KRAS Director

Interpretation

Method

Next-generation sequencing.

The KRAS gene is sequenced and analyzed for mutations, including in KRAS codons 12, 13, 61, 117, and 146. This test can normally detect a heterozygous mutation if it is present in more than about 5% of the cells in the sample. This test was developed and its performance characteristics determined by the Department of Laboratory Medicine at the University of Washington.

Reference Range

See individual components

Ref. Range Notes

Results will be reported as either positive or negative for mutation.

Guidelines

Ordering & Collection

Specimen Type

Tumor Tissue, Purified DNA, accompanied by a PATHOLOGY REPORT for the tested tissue.

Collection

Requirements for Specimen Selection

To ensure clinically relevant results, the most recent and/or metastatic sample is preferred to older specimens, provided sufficient tumor is present (see point 2).
To ensure detection of all types of mutations there should be at least 10% tumor cells in the tissue area processed for DNA for mutation detection and 20% tumor cells for microsatellite instability evaluation. If there is more than one tissue block, please provide the block that has the greatest percentage of neoplastic nuclei.
Tissue samples and pathology reports will be reviewed by directors upon receipt for acceptability prior to testing. Director consultation for tissue selection is available if needed (contact Genetics lab).

Specimen Types

Tissue samples

Send one of the following:

Slides: 1 slide at 4-micron thickness stained with hematoxylin-and-eosin (H&E) AND 10 unstained, non-baked slides at 10-micron thickness (a minimum of 5 unstained slides is acceptable). Unstained slides can be on charged or uncharged slides.
Tissue Blocks: Provide complete formalin-fixed tissue block containing tumor tissue. Tissue block will be returned at completion of testing.
Fresh/frozen tissue: 5 microgram tissue in cell culture medium or frozen tissue stored at -20C. Tumor percentage will not be determined prior to sequencing studies.

NOTE: In order to ensure that enough DNA is obtained, the minimum acceptable tissue area is 10 square millimeters when ten 10-micron slides are supplied (1 cubic millimeter of tissue).

Purified DNA

5 micrograms ANDa reference hematoxylin-and-eosin (H&E) stained slide and pathology report required.

Bone Marrow

1 to 2 mL Bone Marrow in LAVENDER TOP (EDTA) tube

Blood

6 mL blood in LAVENDER TOP (EDTA) tube.

Alternative specimens may be acceptable with approval (contact: 206-598-1149).

For ADD-ON after prior testing, contact Genetics lab.

Unacceptable samples

We cannot accept decalcified samples or tissue samples treated with fixatives other than formalin.

Quantity:

Requested:

Tissue: 10 unstained slides (10-micron thickness) plus one H&E-stained slide.
Extracted DNA: 5 microgram Bone Marrow: 2 mL
Blood: 6 mL

Minimum:

Tissue: 5 unstained slides (10-micron thickness) plus one H&E-stained slide.
Extracted DNA: 100-250 nanograms Bone Marrow: 1 mL
Blood: 3 mL

Forms & Requisitions

Genetics Requisition

Providers with access to the UW implementation of Epic (i.e., FHCC, HMC, SCCA, UWMC, UWNW) may order this test using the order "UW Genetics and Solid Tumor Test Request." See tip sheet for more information (internal link).

Handling Instructions

Attach a copy of the pathology report for the tumor sample being submitted.

Hold slides or tissue blocks at room temperature.

Outside Laboratories: Ship at room temperature.

Stability: unstained slides or tissue blocks stable at room temperature for at least 2 years

Quantity

requested: Amounts as noted above
minimum: Amounts as noted above

Processing

Performance

LIS Dept Code

Genetics (GEN)

Performing Location(s)

UW-MT	Genetics Attention: Genetics Lab Clinical lab, Room NW220 University of Washington Medical Center 1959 NE Pacific Street Seattle, WA 98195 Tel: 206-598–6429 M–F (7:30 AM–4:00 PM) Fax: 206-616-4584 Lab email: cgateam@uw.edu Tel (EXOME only): 206-543-0459	Faculty Jillian Buchan, PhD, FACMG Runjun Kumar, MD, PhD Regina Kwon, MD, MPH Christina Lockwood, PhD, DABCC, DABMGG Abbye McEwen, MD, PhD Colin Pritchard, MD, PhD Vera Paulson, MD, PhD Eric Konnick, MD, MS He Fang, PhD

Frequency

Run at least once a week; Typical Turnaround: 3 weeks *Turn around times may vary based on factors such as tissue acquisition and insurance preauthorization.

Available STAT?

Billing & Coding

CPT codes

81275, 81276

Billing Comments

For pricing information, contact Client Support Services 206-520-4600 or 800-713-5198.

LOINC

21703-4

Interfaced Order Code

UOW2114