Tumour mutational burden — usually abbreviated as TMB — is a measurement of how many genetic mutations are present in a tumour. The more mutations a cancer carries, the more it tends to look different from normal cells to the immune system. Because immunotherapy drugs work by helping the immune system find and attack cancer, …
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HER2 — also known as ERBB2 — is a gene that drives the growth of cancer cells when it is overactive. Although HER2 amplification is best known in breast and gastric cancers, it also occurs in colorectal cancer and, until recently, was a finding without a dedicated treatment. That has changed substantially. Two HER2-targeted therapies …
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A BRAF mutation is found in approximately 8 to 12% of colorectal cancers and identifies a biologically distinct subtype of the disease with its own treatment implications. The great majority of BRAF mutations in colorectal cancer are a specific change called V600E. This mutation carries two important clinical consequences: it predicts that standard anti-EGFR targeted …
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KRAS and NRAS are two of the most commonly tested genes in colorectal cancer. When either gene carries a mutation — a change that causes it to malfunction — the result has direct consequences for your treatment plan. Most importantly, KRAS and NRAS mutations predict that a class of targeted drugs called anti-EGFR therapy will …
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MMR-deficient, often written as dMMR, means that one or more of the proteins responsible for repairing mistakes in a cell’s DNA are missing or not working properly. When these repair proteins are lost, errors in DNA can accumulate over time, contributing to the development of cancer. Finding dMMR in a tumour has important implications for …
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Mismatch repair (MMR) and microsatellite instability (MSI) testing are among the most important biomarker tests performed on colorectal cancers. Every colorectal cancer — whether found on a biopsy or in a surgical specimen — should be tested for this biomarker. The results tell your doctor whether your cancer’s DNA repair system is working normally or …
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PD-L1 (programmed death-ligand 1) is a protein found on the surface of cells — including cancer cells and immune cells within tumours — that acts as a brake on the immune system. Under normal circumstances, PD-L1 helps prevent the immune system from attacking healthy tissue by binding to a receptor called PD-1 on T cells, …
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NTRK fusions are chromosomal rearrangements that fuse one of three genes — NTRK1, NTRK2, or NTRK3 — to a partner gene, producing an abnormal fusion protein that continuously drives cancer cell growth. The NTRK genes normally encode a family of receptor proteins called tropomyosin receptor kinases (TRK A, B, and C), which play important roles …
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BRAF is a gene that encodes a protein kinase — an enzyme that acts as a relay in a signalling chain called the MAPK pathway, which controls cell growth and division. In normal cells, BRAF passes signals from activated surface receptors (including RAS proteins) downstream to the rest of the cell in a tightly regulated …
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RET is a gene that encodes a receptor protein involved in signalling pathways that regulate cell growth, survival, and differentiation during normal development. In healthy adult lung tissue, RET activity is minimal. In approximately 1–2% of non-small cell lung cancers, a chromosomal rearrangement fuses the RET gene to a partner gene, creating an abnormal fusion …
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