Colorectal cancer: the advantages and performance of the KRAS test
The KRAS test is used to identify the type of KRAS gene and, therefore, the state or form of the KRAS protein, whether normal (also called ‘wild type’) or ‘non-normal’ (mutated)
The KRAS gene is, therefore, a biomarker
It makes it possible to predict the response to certain types of drugs targeting the epidermal growth factor receptor, known as EGRF: if the gene results in the production of a normal protein, the effectiveness of the action of such drugs will be greater.
It is therefore important to determine what type of tumour people have so that they can receive the most appropriate and effective treatment.
This is possible with a new genetic test, the KRAS test, the result of which allows the doctor to choose the most effective treatment for each patient.
The KRAS test, which has been available since the end of 2007, is a simple, precise and non-invasive test because, in most cases, it can be easily performed on already available tumour tissues, e.g. those derived from tumour biopsy.
From these tissues it is necessary to isolate the DNA of the tumour cells, and then to analyse the KRAS gene by means of a very specific reaction that allows individual pieces of DNA to be ‘read’.
The results, available after about a week, make it possible to determine precisely and unambiguously whether the KRAS gene is normal, which is the case in about 60% of patients, or mutated.
Once the KRAS status has been determined, the doctor can choose the most suitable treatment for the patient to obtain the greatest therapeutic benefit
Testing for the KRAS gene is simple and non-invasive, and analyses the DNA of tumour cells already available from tissue samples taken during biopsy and other analyses.
The presence of a mutated KRAS gene in cancer cells can be detected by a very sensitive and specific method: quantitative PCR (qPCR), which allows the DNA of the KRAS gene to be selectively amplified.
The laboratory procedure used to determine KRAS status can be summarised in six successive steps:
STEP 1
Before starting the KRAS test, an anatomic pathologist selects a tissue sample from a slide with a sufficient quantity of tumour cells from which to extract the DNA on which to perform the KRAS test
STEP 2
The tissue sample is then removed from the slide so that the test can be performed and the KRAS ‘status’ can be determined.
STEP 3
The tumour tissue DNA is purified from the tissue sample.
STEP 4
The tumour tissue DNA is checked for purity according to quality control procedures.
STEP 5
PCR is a highly sensitive and specific test that uses labelled probes to amplify DNA and determine the presence of mutated KRAS.
STEP 6
The amplification product is measured to see whether the tumour expresses a normal or mutated KRAS gene.
In this way, based on the tumour’s KRAS status, the therapy to be administered to the patient can be customised.
Read Also
Emergency Live Even More…Live: Download The New Free App Of Your Newspaper For IOS And Android
Soft Tissue Sarcomas: Malignant Fibrous Histiocytoma
Brain Tumours: Symptoms, Classification, Diagnosis And Treatment
Pediatric Brain Tumors: Types, Causes, Diagnosis And Treatment
Brain Tumours: CAR-T Offers New Hope For Treating Inoperable Gliomas
Lymphoma: 10 Alarm Bells Not To Be Underestimated
Chemotherapy: What It Is And When It Is Performed
CAR-T: An Innovative Therapy For Lymphomas
What Is CAR-T And How Does CAR-T Work?
Radiotherapy: What It Is Used For And What The Effects Are
Craniosynostosis Surgery: Overview
Pediatric Malignancies: Medulloblastoma
Soft Tissue Tumours: Leiomyosarcoma