Gastric cancer, also known as stomach cancer, remains a significant global health challenge. Its early stages often present with vague symptoms, leading to late diagnosis when treatment options are limited and prognosis is poor. Despite declining incidence rates in some regions, it remains a leading cause of cancer-related deaths worldwide. Improving detection and guiding effective treatment strategies for gastric cancer requires advanced tools. Biomarkers are a promising approach to address these challenges.
What Are Biomarkers?
A biomarker is a measurable indicator of a biological state or condition within the body. These indicators can be biological molecules, such as proteins, genes, or cellular changes, found in tissues, blood, or other bodily fluids. Biomarkers offer insights into normal biological processes and abnormal ones, such as disease progression or a body’s response to medical intervention.
In cancer, biomarkers specifically indicate the presence of cancer, its stage, or how it might react to treatment. They can be substances secreted by a tumor or a specific bodily response to the cancer. These indicators help differentiate between an affected patient and a healthy individual, providing valuable information for medical professionals.
The Role of Biomarkers in Gastric Cancer
Biomarkers hold particular significance for gastric cancer due to management difficulties. The disease often exhibits a high degree of heterogeneity, meaning its characteristics and behavior can vary considerably among individuals.
Biomarkers enable earlier detection, which can substantially improve survival rates. They also contribute to more accurate prognosis, helping predict how the disease might progress or respond to therapies. This allows for personalized medicine approaches, moving away from a general treatment model to one tailored to an individual’s unique tumor profile.
Key Biomarkers for Gastric Cancer
Several biomarkers are used to understand and manage gastric cancer. Human Epidermal growth factor Receptor 2 (HER2) is a protein involved in cell growth. Its overexpression, observed in 5–25% of gastric cancer cases, makes the tumor susceptible to targeted therapies like trastuzumab.
Programmed Death-Ligand 1 (PD-L1) is expressed on tumor and immune cells, helping cancer cells evade the immune system. Its presence guides immunotherapy, as drugs targeting PD-L1, such as pembrolizumab, can restore the body’s immune response. Carcinoembryonic Antigen (CEA) and Carbohydrate Antigen 19-9 (CA19-9) are common blood tumor markers. They are primarily used for monitoring treatment response and detecting recurrence, though their sensitivity for early diagnosis is limited.
Newer approaches include liquid biopsy markers like Circulating Tumor DNA (ctDNA) and MicroRNAs. CtDNA consists of DNA fragments shed by tumor cells into the bloodstream, offering a non-invasive way to detect cancer and monitor treatment. MicroRNAs are small RNA molecules found in circulation that show promise as non-invasive diagnostic tools for gastric cancer.
How Biomarkers Guide Gastric Cancer Management
Biomarkers play an active role throughout a patient’s journey with gastric cancer, influencing various aspects of care. In diagnosis and staging, biomarkers can provide additional information to confirm the presence and extent of the disease, complementing traditional methods. Specialized molecular profiling using biomarkers offers a more accurate characterization of tumors.
For prognosis, biomarkers help predict the likely course of the disease and patient outcomes. For example, HER2 overexpression can be associated with a poorer prognosis in some gastric cancer patients. This predictive power helps clinicians and patients make informed decisions about treatment intensity and follow-up.
Biomarkers are important in guiding treatment selection for personalized medicine. Identifying specific biomarkers like HER2 or PD-L1 allows doctors to choose targeted therapies or immunotherapies. These treatments are designed to attack cancer cells with particular molecular characteristics, leading to more effective treatments with potentially fewer side effects.
Beyond initial treatment decisions, biomarkers are also used to monitor treatment response and detect recurrence. Blood tests for markers like CEA, CA19-9, or ctDNA can indicate if a therapy is working or if the cancer has returned. This ongoing monitoring allows for timely adjustments to treatment plans, optimizing patient care and improving long-term outcomes.