Gene Expression Profiling for Breast Cancer Prognosis in Chinese Populations

To investigate a quantitative reverse transcription polymerase chain reaction (QRT-PCR) assay different from 21-gene assay which can be used to prognosticate the risk of recurrence in patients with estrogen receptor (ER) positive, lymph node (LN) negative breast cancer. To accurately determine the relationship between the Recurrence Score (RS) derived from our assay and the risk of distant recurrence in Chinese patients with LN negative and positive breast cancer through the analysis of paraffin tissues. We obtained archival paraffin-embedded tissues from patients with invasive breast cancer and varying axillary lymph node involvement. QRT-PCR reaction was performed by using the method of SYBR Green I dye with primers. Expression of the 21-genes was converted to RS by a prespecified algorithm. We then assessed the probability of the test to accurately predict distant recurrence-free survival in this retrospective cohort. Ninety-three patients were eligible based on gene expression profiles. In our population, most breast cancer patients were premenopausal (82.6%), at early stage (93.6%) and ER positive (91.4%). Median follow-up was 65.9 months. The 5-year recurrence-free survival rate for the group was 58.8%. The concordance between the reverse transcription-PCR and immunohistochemical (IHC) measurement for ER, progesterone receptor (PgR), and HER-2 determinations was high and comparable. High RS was predictive of an elevated risk of relapse (p