A number of prognostic and/or predictive genomic signatures for breast cancer have been developed by Genome Institute of Singapore (GIS). In the past 1 year, GIS has developed protocols and methods to conduct expression assays from formalin-fixed, paraffin-embedded (FFPE) tumor specimens. A study on 800 tumor samples is planned to analyze these gene signatures and compare them with conventional clinical prognosticators and predictors. As the investigators plan to use archival tumor samples that dates back to the 1990s, the aim of this pilot study is to first analyze 10 anonymized samples to determine the feasibility of running these assays on old archival blocks. The information generated will help us determine whether very old samples (diagnosed before 2000) may be selected for the actual study.

Up to 10 archival breast tumor blocks will be obtained from the Department of Pathology, NUH - half of these blocks will be from patients who were diagnosed before year 2000, and the other half of the blocks will be from patients diagnosed between year 2000-2005 (control specimens). Basic tumor and patient information will be collected without patient identifiers - grade, stage, ER/PR/HER2 status, treatment received, outcome data. 8-10 ten-micron sections will be cut from each tumor block. RNA will be extracted from the tumor sections using the Roche High Pure FFPE RNA Micro Kit. RNA will be profiled using the Illumina Veracode assay and the Affymetrix Quantigene assay. RNA extraction and gene expression profiling will be performed by collabroators at the Genome Institute of Singapore.

Inclusion Criteria:

• Half of these blocks will be from breast cancer patients who were diagnosed before year 2000.
• Half of the blocks will be from breast cancer patients diagnosed between year 2000-2005 (control specimens).

Exclusion Criteria:

• Breast cancer patients diagnosed after year 2005.

Archival tumor samples that dates back to the 1990s