Abstract 4132: MicroRNA-1246 as a novel candidate for a blood-based biomarker in ovarian cancer patients
Authors: Kuhlmann Jan Dominik , Hahn Stephan , Baraniskin Alexander , Wimberger Pauline , Kasimir-Bauer Sabine 
Published: August 2012

Abstract
Background: Ovarian Cancer is the leading cause of death among female malignancies and despite advances in treatment, more than 50% of patients will experience recurrence. For therapy-monitoring, it would be highly desirable to establish a blood-based biomarker. In this regard, microRNA (miRNA), a class of small regulatory RNA molecules, which provide a profound stability in the circulation, are of particular interest. Here, we analyzed circulating miRNA expression in sera of primary ovarian cancer patients before surgery and after platinum-based chemotherapy and correlated these findings with clinicopathological parameters of the patients. Patients and Methods: Circulating total RNA, including miRNA-fraction, was purified from sera of ovarian cancer patients and healthy controls (400 µl serum per patient, mirVana PARIS Kit, Ambion). Screening for differentially expressed miRNA was performed with miRNA microarray analysis (Agilent) of sera from ovarian cancer patients before surgery (n= 0) and healthy donors (n=6). Array data were validated with real-time PCR (miScript, Qiagen) in sera before surgery (n=53), corresponding sera after chemotherapy (n=43) and healthy controls (n=35). Relative quantification across these samples was allowed by spike-In normalisation with synthetic c. elegans miRNA-54 (cel-miR-54). Therefore, 25 fmol cel-miR-54 were spiked into each serum sample after denaturation and cel-miR-54 signal was quantified with real-time PCR. Normalized C(t) value of a miRNA of interest was calculated as following: C(t)normalized = C(t)candidate - C(t)spike-In. Results: Based on the array data, miR-1246 was identified as up-modulated by approximately 2-fold in the pre-operative serum samples and therefore selected for validation. Relative quantification in the validation cohort confirmed miR-1246 to be significantly up-regulated in sera before surgery in comparison to healthy donors (p = 0.0001). In preoperative sera, expression of miR-1246 with a mean C(t) of 6.3 (range 2.33 - 9.21) was observed and in healthy donors, a mean C(t) of 7.46 (range 4.01- 8.42) was measured. When these results were statistically correlated with clinicopathological parameters of the patients, we revealed significant correlations between miR-1246 expression before surgery and after chemotherapy and residual tumor load (p = 0.022, p = 0.024, respectively). Moreover, miR-1246 expression before surgery significantly correlated with FIGO stage (p = 0.04) and nodal status (p = 0.006), whereas after chemotherapy miR-1246 significantly associated with tumor grading (p = 0.022). Conclusion: Our data suggest circulating miR-1246 as a novel blood-based biomarker candidate for ovarian cancer patients. The clinical follow-up of the patients will further show, whether expression dynamics of miR-1246 before surgery and after chemotherapy could be clinically relevant for therapy monitoring or prognosis.
Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 103rd Annual Meeting of the American Association for Cancer Research; 2012 Mar 31-Apr 4; Chicago, IL. Philadelphia (PA): AACR; Cancer Res 2012;72(8 Suppl):Abstract nr 4132. doi:1538-7445.AM2012-4132