From the National Cancer Institute
Breast cancer cells
Classification and prognosis of invasive breast cancer: from morphology to molecular taxonomy
This article is quite easy to follow. It explains that newer techniques use gene expression profiling to identify certain molecular subtypes of breast cancer. This identification will help clinicians to better assess prognosis, determine treatment options and evaluate response to therapy.
Gene expression profiling is a way of measuring the activity of thousands of genes at once.
Traditionally, the article explains that in order to decide which therapy would be best for the patient, clinicians look at the patient and categorize them according to:
1. Patient age
2. Axilla lymph node status
3. Histological features
4. Hormone receptor status
5. HER2 status
HER2 is the name of a protein that can be found on some types of cancer cells. If this finding is positive, then the tumor may grow more quickly.
The pathology report will show whether or not the cancer cells have receptor cells for estrogen and progesterone:
1. Hormone receptor-positive
2. Hormone receptor-negative
In the table shown in the same article above, three main subtypes are described:
The next table in the same article shows:
Immunophenotyping to approximate molecular subtype using six biomarkersa
– Immunophenotyping is a technique used to study the protein expressed by cells –
There are five tumor subtypes of breast cancer listed in this article:
Phenotypic and molecular characterization of the claudin-low intrinsic subtype of breast cancer
2. Luminal B
3. HER2-enriched, basal-like and claudin-low
– This article lists the above 5, and also says normal breast is a category, and thus names 6 subtypes.
Molecular biology in breast cancer: intrinsic subtypes and signaling pathways.
Wikipedia lists 7 types:
- Basal-like: ER-, PR- and HER2-; also called triple negative breast cancer (TNBC) Most BRCA1 breast cancers are basal-like TNBC.
- Luminal A: ER+ and low grade
- Luminal B: ER+ but often high grade
- Luminal ER-/AR+: (overlapping with apocrine and so called molecular apocrine) – recently identified androgen responsive subtype which may respond to antihormonal treatment with bicalutamide
- ERBB2/HER2+: has amplified HER2/neu
- Normal breast-like
- Claudin-low: a more recently described class; often triple-negative, but distinct in that there is low expression of cell-cell junction proteins including E-cadherin and frequently there is infiltration with lymphocytes.