KRAS GENE MUTATION ANALYSIS
NON-SMALL CELL LUNG CANCER (NSCLC) AND VARIOUS SPORADIC CANCERS
PRIMARY RESISTANCE TO EGFR AND ERBB2 TYROSINE KINASE INHIBITORS
DESCRIPTION - DNA Scanning and Sequencing

ERBB signaling pathways include downstream GTPases encoded by RAS genes. KRAS (KRAS2) is a member of the GTP-binding protein family and is involved in the regulation of signal transduction, genetic instability and apoptosis. Some 15%–30% of lung adenocarcinomas contain activating mutations in the RAS family member KRAS. A single amino acid substitution is responsible for an activating mutation. These mutations are most frequently found in codons 12 and 13 in exon 2, codons 59 and 61 in exon 3, and may be associated with unfavorable outcome. The transforming protein that results is implicated in various malignancies, including lung adenocarcinoma, mucinous adenoma, ductal carcinoma of the pancreas and colorectal carcinoma. Interestingly, EGFR and KRAS mutations are rarely found in the same tumors, suggesting that they have functionally equivalent roles in lung tumorigenesis. Furthermore, EGFR mutations are common in tumors from patients who have smoked less than 100 cigarettes in their lifetimes (“never smokers”), while KRAS mutations more commonly occur in individuals with a history of substantial cigarette use. Smokers with adenocarcinoma of the lung (NSCLCs) are more likely to have KRAS somatic mutations (38%) compared with non-smokers. It has recently been demonstrated that KRAS mutations could also be used to predict primary resistance to known EGFR tyrosine kinase inhibitors gefitinib (Iressa® or erlotinib (Tarceva®). The findings indicate that patients whose lung adenocarcinomas have KRAS mutations will not experience significant tumor regression with either drug.

KRAS Gene Mutation Analysis for Solid Tumors – Non-Small Cell Lung Cancer (NSCLC) and Various Sporadic Cancers – Primary Resistance to EGFR AND ERBB2 Tyrosine Kinase Inhibitors

Test Order Code KRAS-MUTS-S
CPT Codes 83891 x 1, 83898 x 2, 83892 x 2, 83903 x 2, 83904 x 2, 83912 x 1

KRAS Gene Mutation Analysis for Leukemias – Non-Small Cell Lung Cancer (NSCLC) and Various Sporadic Cancers – Primary Resistance to EGFR AND ERBB2 Tyrosine Kinase Inhibitors

Test Order Code KRAS-MUTS-L
CPT Codes 83891 x 1, 83898 x 4, 83892 x 4, 83909 x 2, 83903 x 2, 83904 x 2, 83912 x 1

 

Indications For Testing

KRAS mutation analysis is most appropriate for individuals diagnosed with lung adenocarcinoma. An individual that presents clinical features characteristic of non-small cell lung carcinoma or other sporadic cancers that are treated with EGFR inhibitors. KRAS mutations have also been reported in individuals with:

  • Endometrial carcinoma (not in endometrial hyperplasia)

  • Multiple myeloma (MM) and primary plasma cell leukemia (PPCL) at the early stage

  • Rectal cancer and adenoma

  • Colorectal tumors with poor prognosis

  • Gastric cancers (up to 28%)

  • Pancreatic cancer

This test should be offered in the context of genetic counseling prior to and after test completion.

Turn Around Time

 Up to 7 days. Expedited analysis is available upon request for an additional charge.
Specimen Requirements

TISSUE AND Peripheral Blood

  • Tissue that can be used includes primary tumor, metastases, bronchial lavage, or cell block of pleural fluid. Viable tumor cells must be present.

  • Fresh or ethanl fixed tissue samples are preferred.

  • Formalin-fixed, paraffin-embedded tissue samples are also accepted.

  • Send 3-5 slides of the tumor/biopsy sample as 5-10 micron serial sections without cover-slips. Unstained slides are preferred, but stained slides are accepted.

  • Sample biopsies will be accepted if sent with 2 additional slides. Please include one hematoxylin-eosin stained reference slide. Include a copy of the original pathology report.A similar process should be followed for other solid tumor types.

All pathology specimens should be accompanied by a blood specimen

Peripheral Blood (preferred)

  • All peripheral blood collections require Purple/Lavender-top (EDTA) vaccutainer tubes or Transgenomic’s DNA Analysis Kits only.

  • Adults: 1 tube with 7.5 mL whole blood

  • Children & Infants: 1 tube of 3 mL whole blood

  • A sample submission kit and shipping information can be obtained from Transgenomic Molecular Laboratory by contacting the Client Services Coordinator (1-866-500-GENE).

  • Instead of a blood sample, 1-2 mL of saliva can be collected in an OraGene™ collection cup (REF-OG-1, DNA Genotek Inc, Ottawa, Canada).

  • For transport, ship at ambient temperature or keep samples at 2-8°C (cold pack-preferred) and ship by overnight courier to arrive at Molecular Laboratory within 24 hrs after collection of the specimen. If shipment is delayed by one or two days, the specimen should be refrigerated. Do not freeze the blood specimen. Frozen samples will not be accepted.

Specimen Kits DNA Specimen Collection Kits can be obtained from Transgenomic Molecular Laboratory.
Shipping and Contact Information Transgenomic Molecular Laboratory
12325 Emmet Street Omaha, NE 68164 USA
Phone: (866) 500-GENE / (866) 500-4363 Fax: (402) 452-5447
E-mail: labservice@transgenomiclabs.com
Test Submission  and Patient Consent Forms
Test Methodology DHPLC mutation scanning and DNA sequencing.
Sensitivity The test has been shown to detect KRAS point mutations in sample preparations that contain only 1-2% of mutant KRAS DNA. Extraction of DNA from tissue samples is dependent upon the quality and quantity of the initial sample. Inadequate DNA extraction may occur for up to 20-25% of paraffin-embedded samples. Tumor samples can be a mix of cell types. The composition of the tumor cannot be determined until a pathological analysis is performed. A minimum of 5% tumor cells is required to ensure the accuracy of the KRAS mutation scanning assay.

Accuracy - Mutation scanning by WAVE® DHPLC and SURVEYOR® Nuclease combined with DNA sequencing has an analytical sensitivity of > 99% for the detection of mutations. The test has greater than 99 % accuracy to detect mutations in the regions of the KRAS gene scanned, including codon D816.

Limitations The methodology will detect mutations located only within the regions defined by the primers. If another mutation in the KRAS gene exists, this test will not identify it. Mutations in the KRAS gene are also associated other sporadic cancers. A test to scan additional KRAS gene exons is available upon request. Some sequence alterations detected by this assay will be of unknown clinical relevance. Interpretation of test results should be in the context of the patient’s clinical and family histories, ethnicity, and other laboratory test results.
References

  1. Eberhard, D.A. et al., J. Clin. Oncol. 23, 5900-5909 (2005).

  2. Pao, W. et al. PLOS Med. 2 (3) e73 (2005).

  3. Pao, W. et al. PLOS Med. 2 (1) e 17, (2005).

  4. Castagnola, P. et al. BBA (2005).

OMIM Entries for:

KRAS

190070 V-KI-RAS2 KIRSTEN RAT SARCOMA VIRAL ONCOGENE HOMOLOG; KRAS

Note: The performance characteristics of this test were validated by TRANSGENOMIC Molecular Laboratory. The U.S. Food and Drug Administration (FDA) has not approved this test. However, FDA approval is currently not required for clinical use of this test. The results are not intended to be used as the sole means for clinical diagnosis or patient management decisions. TRANSGENOMIC Molecular Laboratory is authorized under Clinical Laboratory Improvement Amendments (CLIA) to perform high-complexity testing.