299fast, reproducible, tissue-sparing, quantitative, automatable, and can be performed
from archived (formalin-fi xed, paraffi n-embedded tissue) samples. The benefi t of
using realtime-qPCR for cancer diagnostics is that new markers can be readily vali-
dated and implemented, making tests expandable and/or tailored to the individual.
For instance, the proliferation metagene could be used within the context of the
intrinsic subtypes or used as an ancillary test in breast cancer and other tumor types
where an objective and quantitative measure of grade is important for risk stratifi ca-
tion. As more prognostic and predictive signatures are discovered from microarray,
it should be possible to build on the current biological classifi cation and develop
customized assays for each tumor subtype. This approach enables the important
clinical distinction between ER-positive and ER-negative tumors and identifi es
additional subtypes that have prognostic value. The proliferation metagene offers an
objective and quantitative measurement for grade and adds signifi cant prognostic
information to the biological subtypes. It is a robust predictor of survival across all
breast cancer patients and is particularly important for prognosis in Luminal A
(ER-positive) breast cancers, which have a worse outcome than expected when pro-
liferation is high. This supports previous fi ndings that a genomic signature of pro-
liferation is important for predicting relapse in breast cancer, especially in
ER-positive patients.
A study has compared realtime-qPCR results for the assessment of mRNA levels
of ERa, PgR, and the members of the human epidermal growth factor receptor fam-
ily, HER1, HER2, HER3 and HER4 (Labuhn et al. 2006 ). The results were obtained
in two independent laboratories using two different methods, SYBR Green I and
TaqMan probes, and different primers. By linear regression a good concordance
was demonstrated for all six biomarkers. The quantitative mRNA expression levels
of ERa, PgR and HER2 also strongly correlated with the respective quantitative
protein expression levels prospectively detected by EIA in both laboratories. In
addition, HER2 mRNA expression levels correlated well with gene amplifi cation
detected by FISH in the same biopsies. These results indicate that both realtime-
qPCR methods were robust and sensitive tools for routine diagnostics and consis-
tent with standard methods. The simultaneous assessment of several biomarkers is
fast as well as labor effective and optimizes the clinical decision-making process in
breast cancer tissue and/or core biopsies.
Gene Expression Profi ling Gene-expression profi ling with the use of DNA micro-
arrays enables measurement of thousands of mRNA transcripts in a single
experiment. These are being used to develop new prognostic and predictive tests for
breast cancer, and might be used at the same time to confi rm estrogen-receptor sta-
tus and ERBB2 status. Gene expression data of breast cancer samples were used to
assess the correlation between estrogen receptor (ER) and ERBB2 mRNA and clini-
cal status of these genes as established by immunohistochemistry or FISH or both
(Gong et al. 2007 ). Amounts of ESR1 and ERBB2 mRNA, as measured by the
Affymetrix U133A GeneChip, reliably and reproducibly established estrogen-
receptor status and ERBB2 status, respectively. The gene expression tests are 90 %
accurate for both receptors, which make them comparable to, if not better than,
Personalized Management of Cancers of Various Organs