Tumor Marker Makeup
Proteins produced in response to cancer growth or from cancerous tissue
Can be specific or seen in multiple cancer types
Tumor Risk Factors
(in vitro Diagnostic Multivariate Index Assay)
Tests available to detect mutations and offer “risk index”
Programmed cell death, self-destruction
New blood vessel formation, typically embedded within a tumor, allows tumor cells entry into circulation
Tumor at the primary site, small risk
Abnormal cell growth, proliferation and/or differentiation
Multiplication of cells within an organ or tissue, may be controlled by stimuli as a normal response
Tumor aggressive progress, infiltration, high risk
Uncontrolled proliferation involving numerous tumor cells and host cells interactions. Penetration into adjacent tissue of primary site, circulatory system, and spread to distant organs.
Normal cells under cancerous proliferation due to hyperplasia, which is unregulated.
Tumor Marker Utilization
- Determine prognosis
- Guidance of Treatment
- Monitor Treatment
- Determine recurrence
Tumor Marker Utilization: Screening
Useful for patients with a strong family history of a particular cancer. Example: PSA prostate cancer
Tumor Marker Utilization: Diagnosis
In patients with specific clinical symptoms, tumor markers can help identify the source of the cancer and differentiate from other conditions
Examples: CA-125, BRCA1 and BRCA 2
Tumor Marker Utilization: Staging
If a patient does have cancer, tumor marker elevations can be used to help determine how far the cancer has spread into other tissues and organs.
Tumor Marker Utilization: Determine prognosis
Some tumor markers can be used to help doctors determine how aggressive a cancer is likely to be.
Guidance of Treatment
Some tumor markers can provide information about what treatments their patients may have the best response.
Breast cancer patients who are Her2/neu positive are more likely to respond to Herceptin treatment).
Tumor markers can be used to monitor the effectiveness of treatment, especially in advanced cancers. If the marker level drops, the treatment is working; if it stays elevated, adjustments are needed.
Colorectal cancer and CEA testing: information must be used with care; not every colorectal cancer patient will have elevated levels of CEA.
To monitor for cancer recurrence - If a tumor marker is elevated before treatment, low after treatment, and then begins to rise over time, then it is likely that the cancer is returning. (If it remains elevated after surgery, then chances are that not all of the cancer was removed)
Anaplastic (without body)
Tumor Marker Classifications
Catalytic activity vs mass measurements, detected with Immunoassays
AFP, CEA, PSA
CA125, CA15-3, CA19-9
Oncogene and tumor suppressor mutations
Prostate Specific Antigen, level indications
- Enzyme with protease activity in Prostate tissue
- Exists in serum as bound (complexed with another protease inhibitor) or free, higher free PSA ratio in normal, healthy patients
- Total PSA: 2.6-4ng/mL indicates early development
- 4-10mg/mL is diagnostic gray zone
- >10ng/mL have a 50% chance of having cancer
hCG (Human Chorionic Gonadotropin)
- Synthesized by trophoblast calls in placenta (used for pregnancy detection), made of 2 Alpha and Beta units
- Beta is specific to hCG
- Increased levels assoc. with Trophoblastic tumors, choriocarcinoma, testicular tumors, ovarian tumors
- Immunoassay uses ß-hCG
Normally produced in fetal tissues, then decline after birth
A rise later in life (60yrs) can indicate cancer formation
AFP (Alpha feto protein)