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• Bio-Specific Medicine
  • A Bio-Specific Approach
  • The Role of BioMarkers
  • Biomarkers in Practice
  • Personalized Therapy
• Testing for Biomarkers
  • Biomarker Testing
  • Screening Tools
  • Challenges
  • Who and When to Test
• Advisory Council

Biomarker Testing

How to Test There are several biomarker tests that are available, and many more are currently being researched. They evaluate large numbers of proteins and genetic patterns in cancer tumor tissues, and are usually ordered by pathologists. Many times, the type of tumor indicates which biomarker tests would be performed.

Types of Tests Screening tools vary according to the analysis needed.

• Proteomic analyses (e.g., 2D gel electrophoresis, liquid chromatography, mass spectrometry) are used to identify, characterize, and quantify protein biomarkers¹ (e.g., PCa for prostate cancer², CA-125 in ovarian cancer).³
• Gene expression analyses (e.g., microarray, Q-PCR) recognize genetic variants and identify certain gene abnormalities as possible causes for the tumor.⁴
• Chromosomal abnormalities analyses (e.g., ImmunoHistoChemistry and FISH) are used to identify gene abnormalities (e.g., HER-2 expression in breast cancer).^{4, 6}

Sampling of Biospecimens Samples may be biological fluids (e.g., blood [plasma/serum] or urine) or tissues/cells. Solid samples are acquired (biopsied) using a variety of techniques, which can be more or less invasive according to tumor location. Needle aspiration, endoscope, incision, and excision are the most common biopsy types used in cancer diagnoses.⁵

• Needle aspiration uses a needle with a syringe to withdraw fluids and pieces of tissue from the tumor. Different needle sizes may be used according to the tissue sample required. The physician can guide the needle by following its location on an ultrasound or CT scan.⁵
• An endoscope biopsy is used to take tissue samples and determine if cancer is present, and, if so, the type. A thin, flexible, lighted tube (endoscope) with a lens or a video camera allows the physician to view potential tumor sites.⁵
• Excisional biopsy is used to remove the entire tumor while the patient is under anesthesia.⁵
• An incisional biopsy removes only a portion of the tumor. Incisional biopsies are generally reserved for tumors that are larger, and are usually performed under local anesthesia.⁵