C-Reactive Protein as an Indicator of Cancer

Open Access
Author:
Bohm, Kelley Jean
Area of Honors:
Health Policy and Administration
Degree:
Bachelor of Science
Document Type:
Thesis
Thesis Supervisors:
  • Dr Rhonda Be Lue, Thesis Supervisor
  • Rhonda BeLue, Thesis Supervisor
  • Marianne Messersmith Hillemeier, Faculty Reader
  • Rhonda BeLue, Honors Advisor
Keywords:
  • c-reactive protein
  • cancer
  • biomarker
Abstract:
PURPOSE: Many conflicting reports exist concerning the use of C-reactive protein (CRP) as a biomarker to detect cancer. Several studies have found conflicting evidence of the relationship between CRP and the occurrence of cancer in some populations. Some studies show a positive relation between cancers such as lung and ovarian cancer, and elevated plasma CRP levels. Other studies show no relation between cancer onset and CRP. This study looks at the relation of CRP and cancer and investigates the utility of CRP as a screening method for cancer in a US population based sample. METHODS: I used extant data from the National Health and Nutrition Examination Survey (NHANES), years 2005-2006. Logistic regression was used to determine the impact of CRP protein levels on cancer controlling for smoking status, gender, age, cardiovascular disease and BMI. CRP was assessed dichotomously as either high (>0.5 mg/dL) or low (<=0.5 mg/dL) according to results from a sensitivity analysis. RESULTS: Approximately a fifth (19.8%) of participants showed elevated levels of CRP (above 0.5mg/dL). People with elevated CRP had reduced odds of not having cancer (0.684 odds ratio, 95% confidence interval, 0.525 - 0.890) with a sensitivity of 30 and a specificity of 76. Odds ratios for individual cancers differed from cancer taken as a whole. CONCLUSION: C-reactive protein is not a specific predictor of cancer. While elevated plasma levels of CRP may be present in cancer patients, it is a very non-specific marker of inflammation and can be caused by many other conditions.