CK-19 expression by RT-PCR in the peripheral blood of prostate cancer patients

Abstract

4636 Background: Presence of epithelial cells in the peripheral blood of prostate cancer patients correlates with adverse prognostic factors and seems to impart a poorer prognosis in terms of disease free and overall survival in several series in the literature. Sensitive RT-PCR-based techniques for detection of epithelial antigen expression, such as CK-19, in the in the peripheral blood mononuclear fraction (PBMN) of prostate cancer (PC) patients may allow the detection of tumor progression at molecular level. Methods: We studied CK-19 expression by RT-PCR (as described in Datta YH et al. J Clin Oncol 1994,12:475–482) in PBMN samples of 10 control men and serially in 44 patients with PC every three months for 18 months. PSA progression was defined as any elevation in PSA values that was confirmed by two other sequential measurements. We considered time to PSA progression as the time interval in months from study entry to the first of the three aforementioned progressively elevated PSA levels. Chi-square and Fisher exact tests were used to evaluate correlations between categorical variables. Overall survival was computed from the collection of the first sample for CK-19 determination. Overall survival comparisons between groups with CK-19 positive and negative results were conducted by the Peto-Wilcoxon test. Results: None of the 10 normal control men expressed CK-19 in their PBMN. In the patients, CK-19 positivity at entry was not associated with age, Gleason score, clinical stage, PSA or Alkaline Phosphatase. Interestingly, having at least one positive CK-19 result during follow up correlated significantly with time to PSA progression (p = 0.049), specially in the subgroup of metastatic patients (p = 0.032). Conclusions: We conclude that CK-19 expression by RT-PCR in the PBMN of PC patients correlates with time to PSA progression. Further studies are needed to confirm these findings. No significant financial relationships to disclose.