C-Reactive Protein (CRP) is a substance found in the blood that acts as a general marker of inflammation or infection within the body. Produced by the liver, its presence indicates an inflammatory response. CRP levels are measured to help assess the degree of inflammation, though they do not pinpoint the specific cause or location.
What is C-Reactive Protein (CRP)?
C-Reactive Protein is classified as an “acute-phase protein,” meaning its concentration in the bloodstream increases rapidly in response to inflammation or tissue injury. It is synthesized by the liver, primarily stimulated by signaling molecules like interleukin-6 (IL-6) released by immune cells. CRP is a component of the body’s innate immune system, playing a role in recognizing and binding to damaged cells or certain microbes to initiate their clearance. Healthy individuals maintain very low levels of CRP, below 1.0 milligrams per liter (mg/L). A noticeable elevation above this baseline indicates an active inflammatory process.
The Link Between Inflammation and Cancer
Chronic inflammation can create an environment that promotes the development and progression of cancer. It can damage cellular DNA and alter how cells grow and divide, potentially leading to tumor formation. Inflammatory cells within the tumor microenvironment release molecules like cytokines, which can stimulate the growth of blood vessels that supply tumors with oxygen and nutrients, a process known as angiogenesis. Tumors themselves can induce an inflammatory response, causing the release of various inflammatory markers, including CRP. This dynamic creates a feedback loop where cancer growth can fuel further inflammation, contributing to tumor progression and spread.
Cancers Commonly Associated with Elevated CRP
Elevated CRP levels are frequently observed across various cancer types, reflecting the systemic inflammatory response often accompanying tumor growth. Colorectal cancer, for instance, often shows elevated CRP, particularly in advanced or metastatic stages. In lung cancer, high CRP can be linked to tumor burden and the activation of inflammatory pathways. Pancreatic cancer, known for its aggressive nature, also often presents with increased CRP, potentially indicating tumor-induced inflammation and poorer outcomes.
Ovarian cancer has a consistent association with elevated CRP, with studies showing a significantly higher risk for women with CRP concentrations above 10 mg/L. Gastric cancer patients can also exhibit elevated CRP, which may serve as an indicator of advanced disease and potential for metastasis. Lymphomas and kidney (renal) cancers are other malignancies where elevated CRP levels are frequently noted, often correlating with disease activity and spread.
The Significance of High CRP in Cancer
CRP is a non-specific marker, meaning it indicates inflammation but does not diagnose cancer itself. In individuals already diagnosed with cancer, elevated CRP can serve as a prognostic indicator. High CRP levels may correlate with more advanced disease stages, increased tumor burden, and the presence of metastases. It can also offer insights into a patient’s likely response to treatment, with persistently high levels sometimes indicating a less favorable prognosis or resistance to certain therapies. Medical professionals interpret CRP levels in conjunction with other diagnostic tests and the patient’s overall clinical picture to gain a comprehensive understanding of their condition.
Other Causes of Elevated CRP
Elevated CRP levels are not exclusive to cancer and can be caused by numerous other conditions. Acute infections, whether bacterial or viral, are common causes, leading to a rapid and significant rise in CRP levels, often exceeding 50 mg/L. Chronic inflammatory diseases, such as rheumatoid arthritis, lupus, and inflammatory bowel disease (Crohn’s disease or ulcerative colitis), consistently result in elevated CRP. Other factors contributing to increased CRP include recent trauma or surgery, obesity, and cardiovascular diseases like heart attack or atherosclerosis. Even lifestyle factors such as chronic stress, smoking, and lack of exercise can lead to mild elevations.