Low correlation between Ki67 assessed by qRT-PCR in Oncotype Dx score and Ki67 assessed by Immunohistochemistry
Résumé
Abstract Breast cancers expressing high levels of Ki67 are associated with poor outcomes. Oncotype DX test was designed for ER+/HER2− early-stage breast cancers to help adjuvant chemotherapy decision by providing a Recurrent Score (RS). RS measures the expression of 21 specific genes from tumor tissue, including Ki67 . The primary aim of this study was to assess the agreement between Ki67 RNA obtained with Oncotype DX RS and Ki67 IHC . Other objectives were to analyze the association between the event free survival (EFS) and the expression level of Ki67 RNA ; and association between RS and Ki67 RNA . Herein, we report a low agreement of 0.288 by Pearson correlation coefficient test between Ki67 IHC and Ki67 RNA in a cohort of 98 patients with early ER+/HER2− breast cancers. Moreover, Ki67 RNA high tumors were significantly associated with the occurrence of events ( p = 0.03). On the other hand, we did not find any association between Ki67 IHC and EFS ( p = 0.26). We observed a low agreement between expression level of Ki67 RNA and Ki67 protein labelling by IHC. Unlike Ki67 IHC and independently of the RS, Ki67 RNA could have a prognostic value. It would be interesting to better assess the prognosis and predictive value of Ki67 RNA measured by qRT-PCR. The Ki67 RNA in medical routine could be a good support in countries where Oncotype DX is not accessible.
Domaines
Sciences du Vivant [q-bio]| Origine | Fichiers éditeurs autorisés sur une archive ouverte |
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