GATA2 expression and biochemical recurrence following salvage radiation therapy for relapsing prostate cancer.

Abstract

High GATA2 expression has been associated with an increased risk of poor clinical outcomes after radical prostatectomy; however, this has not been studied in relation to risk of biochemical recurrence (BCR) after salvage radiation therapy (SRT) for recurrent prostate cancer after radical prostatectomy. Our aim was to evaluate the association between protein expression levels of GATA2 in primary prostate cancer tumour samples and the risk of BCR after SRT. 109 males who were treated with SRT were included. The percentage of cells with nuclear staining and GATA2 staining intensity were both measured. These two measures were multiplied together to obtain a GATA2 H-score (range 0-12) which was our primary GATA2 staining measure. In unadjusted analysis, the risk of BCR was higher for patients with a GATA2 H-score >4 (hazard ratio = 2.04, p = 0.033). In multivariable analysis adjusting for SRT dose, pre-SRT PSA, pathological tumour stage and Gleason score, this association weakened substantially (hazard ratio = 1.45, p = 0.31). This lack of an independent association with BCR appears to be the result of correlations between GATA2 H-score >4 and higher pre-SRT PSA (p = 0.021), higher Gleason score (p = 0.044) and more severe pathological tumour stage (p = 0.068). Higher levels of GATA2 expression appear to be a marker of prostate cancer severity; however, these do not provide independent prognostic information regarding BCR beyond that of validated clinicopathological risk factors. Advances in knowledge: A higher GATA2 expression level appears to be correlated with known measures of prostate cancer severity and therefore is likely not an independent marker of outcome after SRT.