Test for Colon Cancer Assignment 2022

Running head: TEST FOR COLON CANCER 1
Molecular Biomarker
Student’s Name
Professor’s Name
Institution Affiliation
Date

TEST FOR COLON CANCER 2
Introduction
Standard Molecular Biomarker is a test that is carried out in the histopathology laboratory
during the process of diagnosing for colon cancer. The standard molecular biomarker is useful in
determining the treatment of colon cancer. It gives guidelines for conventional chemotherapy
methods and identifies the effective therapies for the treatment of colon cancer (Sepulveda et al,
2017).
Principles of Standard Molecular Biomarker
The epidermal growth factor receptor (EGFR). Due to the increased understanding of the
colon cancer pathways, it has resulted to the increase of monoclonal antibodies to the EGFR,
panitumumab so that to block EGFR, thus preventing the activation of the transduction pathway
signals that uses p13-AKT, SRC and RAS enzymatic reactions with ligands like EGFR
Mismatch repair deficiency (dMMR). It causes several somatic mutations to produce neo-
antigens. The dMMR tumors can respond to the blockage of immune checkpoints such as PD1,
PD-LI, LAG-3, and IDO because of the presence of neo-antigens. (Morelli et al, 2015).
BRAF. Oncogene that is present in the RAS-RAF-MAPK pathway which has adversative
prognosis in all the treatments.
PIK3CA. It is a proto-oncogene which encodes for the PI3K involved in the EGFR
tyrosine domain. In recent studies have shown that the mutations of the exon 20 of this proto-
oncogene can act as a target for anti- EGFR therapy resistance. This domain leads to activation
of AKT- mTOR pathway after phosphorylation of AKT.

TEST FOR COLON CANCER 3
PTEN. It is a tumor – suppressor gene which encodes a protein used in suppressing the PI3-
AKT signal path. It lacks consensus and acts as a predictive marker of anti-EGFR treatment
(Punt, Koopman & Vermeulen, 2017)
.
How Molecular Biomarkers are used in Colon Cancer Treatment
The molecular markers predict responses to a particular treatment or therapy that is called
the predictive biomarkers. Treatment of monoclonal antibody marks the epidermal growth factor
receptor and bind EGFR extracellular zone, thus, leading to the blockage of the signal pathways
of EGFR. For colon cancer (colorectal cancer,) patients, Anti- EGFR has been the main target
used for colorectal cancer (CRC) therapies. CRC therapies require the knowledge of genes
mutational within the pathways as the predictive biomarkers of responses towards CRC
treatments.
The CRC patients who have the KRAS triggering mutations which affect exon 2codons
12 and 13 were demonstrated through clinical trials but did not show any effects from anti-
EGFR monoclonal antibody treatments. Other guidelines demonstrating the molecular bio-
testing of EGFR signaling pathways in gene mutations that can affect the CRC responses
towards anti- EGFR antibody treatments involves exons of NRAS, BRAF, PIK3CA and PTEN
The DNA mismatch repair (MMR) status of colorectal cancer might show predictive values in
specific clinical environments. When testing for the CRC patients, MMR is recommendable in
all patients so that to perform a workup testing for the evaluation of any possible Lynch
syndrome. For the patients with immunotherapy, the molecular biomarker demonstrated that it is