Quantitative Pathology

Breast Biomarkers for Human Epidermal Growth Factor Receptor 2 and Estrogen and Progesterone Receptors

Human Epidermal Growth Factor Receptor 2 (HER2)

HER2 in breast carcinoma is evaluated by the current CAP and National Comprehensive Cancer Network-recommended, FDA-approved immunohistochemical and fluorescence in-situ hybridization (FISH) methods.

The first method employs an immunohistochemical study for HER2 with immunoreactivity determined by quantitative light microscopy. Tumors are classified as negative, indeterminate or positive, depending on the extent and intensity of HER2 cytoplasmic membrane immunoreactivity. Negative and positive cases are reported accordingly. Indeterminate cases are reflexed to FISH analysis unless otherwise requested; however, some cases may be indeterminate by this method. The second method, if specifically requested, employs FISH analysis alone, without immunohistochemistry.

Specimen submission requirements include:
  • A paraffin block containing representative breast tumor
  • A copy of the pathology report with the appropriate requisition

HER2 Reference: HER2 Testing in Breast Cancer: National Comprehensive Cancer Network Task Force Report and Recommendations. Journal of the National Comprehensive Cancer Network: 2006(July):4: S1-S22, (Supplement 3).

Estrogen and Progesterone Receptor Analysis in Tumor

Estrogen and progesterone receptors in breast carcinoma and other tumors known to express these hormone receptors are evaluated by immunohistochemical study with quantitation. The immunoreactive tumor cells expressing estrogen or progesterone receptor activity are reported as a percent of the total number of tumor cells evaluated. Receptor reactivity is also reported as negative or positive, depending on the expression observed.

Specimen submission requirements include:
  • A paraffin block containing representative breast tumor
  • A copy of the pathology report with the appropriate requisition

Additional Breast Biomarkers Available: Assessment of Tumor Deoxyribonucleic Acid (DNA) Ploidy and Cell Proliferation

Tumor DNA ploidy is determined by flow cytometry in formalin-fixed, paraffin-embedded tissue. Proliferation is analyzed by employing both DNA flow cytometry with the calculation of the S-phase fraction, as well as the use of MIB-1 (Ki-67) expression, as determined by immunohistochemistry with quantitation.

Specimen submission requirements include:
  • A paraffin block containing representative breast tumor
  • A copy of the pathology report with the appropriate requisition
Quantitative Pathology