An 8-gene qRT-PCR-based gene expression score that has prognostic value in early breast cancer.
BACKGROUND
Gene expression profiling may improve prognostic accuracy in patients with early breast cancer. Our objective was to demonstrate that it is possible to develop a simple molecular signature to predict distant relapse.


METHODS
We included 153 patients with stage I-II hormonal receptor-positive breast cancer. RNA was isolated from formalin-fixed paraffin-embedded samples and qRT-PCR amplification of 83 genes was performed with gene expression assays. The genes we analyzed were those included in the 70-Gene Signature, the Recurrence Score and the Two-Gene Index. The association among gene expression, clinical variables and distant metastasis-free survival was analyzed using Cox regression models.


RESULTS
An 8-gene prognostic score was defined. Distant metastasis-free survival at 5 years was 97% for patients defined as low-risk by the prognostic score versus 60% for patients defined as high-risk. The 8-gene score remained a significant factor in multivariate analysis and its performance was similar to that of two validated gene profiles: the 70-Gene Signature and the Recurrence Score. The validity of the signature was verified in independent cohorts obtained from the GEO database.


CONCLUSIONS
This study identifies a simple gene expression score that complements histopathological prognostic factors in breast cancer, and can be determined in paraffin-embedded samples.
Sánchez-Navarro
Iker
I
Unidad de Investigación, Instituto de Investigación Sanitaria IdIPAZ, Hospital Universitario La Paz, Paseo de la Castellana 261, Madrid 28046, Spain.
Gámez-Pozo
Angelo
A
Pinto
Alvaro
A
Hardisson
David
D
Madero
Rosario
R
López
Rocío
R
San José
Belén
B
Zamora
Pilar
P
Redondo
Andrés
A
Feliu
Jaime
J
Cejas
Paloma
P
González Barón
Manuel
M
Angel Fresno Vara
Juan
J
Espinosa
Enrique
E
D001943:Breast Neoplasms / Q000175:diagnosis / Q000235:genetics* / Q000401:mortality / Q000556:secondary / Q000628:therapy; D030541:Databases, Genetic; D005260:Female; D020869:Gene Expression Profiling / Q000379:methods*; D015972:Gene Expression Regulation, Neoplastic; D020022:Genetic Predisposition to Disease; D005820:Genetic Testing / Q000379:methods*; D006801:Humans; D053208:Kaplan-Meier Estimate; D008875:Middle Aged; D009367:Neoplasm Staging; D016612:Paraffin Embedding; D016133:Polymerase Chain Reaction; D011237:Predictive Value of Tests; D011379:Prognosis; D016016:Proportional Hazards Models; D015203:Reproducibility of Results; D012189:Retrospective Studies; D018570:Risk Assessment; D012307:Risk Factors; D013997:Time Factors