Colorectal Cancer
Colorectal cancer begins in healthy cels of colon or rectum lining.lt grows into larqe mass called tumor. A tumor can be cancerous or benign. A cancerous tumor is malignant when it grows to other parts of the body. These changes usually tae years to develop. Both genetic and environmental factors can cause the changes.
Multiple techniques are used to diagnose and treat colorectal cancers. Molecular tests are performed to identity specic genes, proteins, and other factors which drive the tumor. Metastatic or recurrent colorectal cancer is preferred for testing.
Results of these tests will help decide whether the treatment options include a type of treatment called targeted therapy.Below is the list of genes that have clinical significance in management of colorectal cancer patients. These genes are analyzed using tests: Microsatellite instability (MSI), OncoCEPT- Solid.
| Agent | Target(s) | FDA-approved Indication(s) | Agent |
| Cetuximab (Erbitux) | EGFR (HER1/ERBB1) | Colorectal cancer(KRAS, NRAS, BRAF wild type) | Cetuximab (Erbitux) |
| Nivolumab (Opdivo) | PD-1 | Colorectal cancer (MSI-H) | Nivolumab (Opdivo) |
| Panitumumab (Vectibix) | EGFR (HER1/ERBB1) | Colorectal cancer (KRAS, NRAS, BRAF wild type) | Panitumumab (Vectibix) |
| Pembrolizumab (Keytruda) | PD-1 | Colorectal cancer (MSI-H) | Pembrolizumab (Keytruda) |
Tests Offered
1. Colocomprehensive
Solid Comprehensive DNA
Genes analyzed NRAS,KRAS, Colocomprehensie BRAF, Her2, PIK3CA & MS$1
2. PDL1
Immunotherapy companion diagnostic FDA approved Biomarkers-PDL1 (22C3 – DAKO, SP263,SP142 – Ventanna) by IHC
Our body’s immune system detects Infected cells and tumour cells and eliminated by cytotoxic T lymphocytes. Normal cells differentiate themselves by expressing a protein signal called PD-L1 to limit harm to surrounding tissue (programmed death ligand 1). This PD-L1 signal is a stop sign meant to prevent cytotoxic T cells from destroying normal cells. T cells use a receptor called PD-1 to identify the PD-L1 signal (programmed death receptor 1). Some tumours can also express the PD-L1 signal in order to deceive the immune system and avoid being detected. Anti-PD-1 therapy works by preventing the interaction between PD-1 and PD-L1 of tumour cells. Patient response from anti-PD-1 therapy (immunotherapy) is associated with PD-L1 expression. Different clones of PDL1 are validated against different targeted immunotherapies and hence specific PDL1 clone is to be requested for IHC test based on Targeted immunotherapeutic drugs for eg. PDL1 22C3 for Pembrolizumab.
3. MMR IHC
MMR by IHC
Defects in the mismatch repair (MMR) pathway describe a well-defined subtype of colorectal cancer (CRC). The presence of MMR could affect the prognosis and benefit of adjuvant treatment. MLH1, MSH2, MSH6, and PMS2 protein expression (as determined by IHC) as well as microsatellite instability analysis (MSI) as determined by PCR are well-established methods for detecting Lynch syndrome (LS), and such testing is advised for all new colorectal cancer diagnosis. MMR IHC and molecular MSI testing are also used as companion diagnostic tests in the selection of specific immuno-oncology therapy in a variety of solid malignancies.