Biomedical Engineering Reference
In-Depth Information
5.3.1
ER and PgR as Prognostic Factors in Breast Cancer
ER-positive (ER+) tumors (Fig. 5.2) are relatively well differentiated
with less aggressive features compared with ER-negative (ER-)
tumors, and comprise up to 75% of the breast cancer cases
worldwide.
Several retrospective population-based studies
have demonstrated that hormone receptor status is an independent
prognostic indicator of outcome in women with breast cancer.
Patients with positive hormone receptors tend to have a better
prognosis: better survival overall, within each stage, and in the
younger and older age groups.
15,16
Breast cancer, recently using
cDNA microarray technology, has been classified as luminal A and B,
HER2, basal, and normal-like molecular subtypes.
15,17,18
Luminal A and
B are recognized as two biologically distinct ER-positive subtypes
of breast cancer; luminal A tumors have lower proliferation rates
and better prognosis than luminal B tumors. The 10-year breast
cancer-specific survival was 79% for luminal A, 64% for luminal B,
19
Figure 5.2
Expression of ER in human breast tumor cells and epithelial cells
of a benign lesion (arrow) detected by immunohistochemistry
using monoclonal antibodies to human ER, clones 1D5 and ER-
2-123 (ER PharmDx
TM
Kit, DAKO).
