Tumor Markers

Key Information

Prognostic (what treatment to use if the tumor should recur)

Estrogen Receptor Assay (ERA)

A laboratory test of breast cancer tissue to determine the responsiveness of the tumor to hormone manipulation, endocrine therapy or removal of the ovaries. About 55% of ER positive tumors will respond to endocrine therapy. Tumors which are negative for estrogen receptors rarely respond to hormone manipulation. The unit of measurement is femtomoles (fmoles) per milligram of tumor.

Types of ERA:

Quantified (measured in femtomoles or fmoles)
Immunohistochemical
A qualitative measurement of the observed number of hormone responsive cells, reported as positive or negative.

Test results
Negative: 3 fmoles or less. ERA may not be performed if tumor is less than 1.0 cm in size or if the tumor is in situ.

Progesterone Receptor Assay (PRA)

A laboratory test of breast cancer tissue to determine the responsiveness of the tumor to endocrine therapy or to removal of the ovaries. Progesterone receptor assay increases the reliability of estrogen receptor assay results: a positive progesterone receptor assay indicates greater likelihood that the patient will respond to hormone therapy. The unit of measurement is femtomoles (fmoles) per milligram of tumor.

Types of PRA:

Quantified (measured in femtomoles or fmoles)
Immunohistochemical
A qualitative measurement of the observed number of hormone responsive cells, reported as positive or negative.

Test results
Negative: 5 fmoles or less. Test may not be performed if tumor is less than 1.0 cm in size or if tumor is completely in situ.

DNA Studies (also called flow cytometery)
A means of measuring certain physical and chemical characteristics of cells or particles as they travel in suspension one by one past a sensing point.

Ploidy analysis
Aneuploid tumors correlate with more aggressive tumors and a greater risk of recurrence.

S-Phase (also called Cell Cycle Analysis)
Percentage of tumor cells synthesizing DNA; patients with high S-phase fraction have less favorable prognosis.

Proliferation Index
High rates indicate actively growing tumors and a greater risk of relapse.

Other Breast Cancer Tumor Markers

C219
Presence is associated with multidrug resistance.

CA 15-3 (Cancer Antigen 15-3)
Elevated in 76% of metastatic breast cancers.

CA 549 (Cancer Antigen 549)
Present in 50% of patients with advanced breast cancer.

Cathepsin D
Distinguishes node-negative patients who may recur (and therefore should receive adjuvant chemotherapy) from node-negative patients who probably will not recur. Elevation indicates a poorer prognosis.

CEA (Carcinoembryonic Antigen)
Persistent elevated levels indicate residual or recurrent metastatic carcinoma.

C-erb B-2 (also called HER-2 or neu oncoprotein)
Associated with larger sized tumors, shorter relapse time and lower survival rate.

C-myc DNA amplification
Elevated (amplified) in breast cancers in older women.

EGFR Epidermal Growth Factor Receptor)
Negative EGFR results correlate with better prognosis regardless of ER status.

Int-2 DNA Amplification
Elevation (amplification) associated with recurrence of tumor.

Go to the Tumor Markers page of the Diagnostic Tests module for more information.