95-Gene Classifier (95GC; Curebest™ 95GC Breast) is one of the multi-gene prognostic assays of estrogen receptor (ER) positive and node negative breast cancer patients, developed 95 gene-set without overlap with that used in another RT-PCR based product (Oncotype DX®). According to the original paper, the prognostic capability of 95GC has been shown even in the “intermediate” patients by microarray-based simulation model, “Recurrence Online”, of above RT-PCR product. But still 95GC has been validated only using the data from single institute and public database. Here we report the result of the first multi-center validation study for this multi-gene assay.
ER-positive and T1-2/N0/M0 breast cancer patients who received only hormonal therapy, without chemotherapy, in adjuvant were enrolled retrospectively. For each patient, fresh frozen tissue was applied to the assay and the classification result of 95GC, “L” or “H”, was used for the validation on 5 year recurrence free survival (5Y-RFS).
We analyzed 75 eligible cases out of 150 enrolled, and found 47 patients classified as “L” showed 96.5% of 5Y-RFS (95%CI:89.5-98.9) while 28 patients of “H” showed 79.1% of 5Y-RFS (95%CI:63.8-88.5). There was a statistically significant difference between RFS of “L” and “H” groups by Log-Rank test (p = 0.0017). Other factors having significant association with 95GC were histological grade (p = 0.0012), “Recurrence Online” (p
95GC was well validated by this first multi-centered retrospective study on 5Y-RFS of ER-positive, node-negative patients who received only hormonal therapy in adjuvant. The result indicates the usefulness of this novel multi-gene assay, as it can classify target patients into 2 groups, “L” and “H”, according to the prognosis of 5Y-RFS.
Clinical trial identification
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All authors have declared no conflicts of interest.