LOH at 6q and 10q in fractionated circulating DNA of ovarian cancer patients is predictive for tumor cell spread and overall survival

BMC Cancer

Research Article

Sabine Kasimir-Bauer¹  Jan Dominik Kuhlmann¹  Pauline Wimberger¹  Rainer Kimmig¹  Micaela Poetsch²  Heidi Schwarzenbach³ 

[1]Department of Gynecology and Obstetrics, University Hospital of Essen, Hufelandstrasse 55, D-45122, Essen, Germany

[2]Institute of Legal Medicine, University Hospital of Essen, Essen, Germany

[3]Institute of Tumor Biology, University Medical Center Hamburg-Eppendorf, Hamburg, Germany

关键词: Circulating DNA;    Loss of heterozygosity;    Disseminated tumor cells;    DNA-fractionation;    Tumor suppressor genes;   

DOI  :  10.1186/1471-2407-12-325

 received in 2012-03-30, accepted in 2012-07-18,  发布年份 2012

来源: Springer

【 摘 要 】

BackgroundWe recently showed that LOH proximal to M6P/IGF2R locus (D6S1581) in primary ovarian tumors is predictive for the presence of disseminated tumor cells (DTC) in the bone marrow (BM). For therapy-monitoring, it would be highly desirable to establish a blood-based biomarker. Therefore, we quantified circulating DNA (cirDNA) in sera of 63 ovarian cancer patients before surgery and after chemotherapy, measured incidence of LOH at four cancer-relevant chromosomal loci, correlated LOH with tumor cell spread to the BM and evaluated prognostic significance of LOH.MethodscirDNA was fractionated into high- and low molecular-weight fraction (HMWF, LMWF) for LOH-profiling, utilizing PCR-based fluorescence microsatellite analysis. BM aspirates were analyzed for DTC by immunocytochemistry using the pan-cytokeratin antibody A45-B/B3.ResultscirDNA levels in the HMWF before surgery were predictive for residual tumor load (p = 0.017). After chemotherapy, we observed a significant decline of cirDNA in the LMWF (p = 0.0001) but not in the HMWF. LOH was prevalently detected in the LMWF with an overall frequency of 67%, only moderately ablating after chemotherapy (45%). Before surgery, LOH in the LMWF at marker D10S1765 and D13S218 significantly correlated with tumor grading and FIGO stage (p = 0.033, p = 0.004, respectively). In both combined fractions, LOH at D6S1581 additionally associated with overall survival (OS) (p = 0.030). Moreover, solely LOH at D10S1765 in LMWF after therapy correlated with DTC in BM after therapy (p = 0.017).ConclusionWe demonstrate the applicability and necessity of DNA-fractionation prior to analyzing circulating LOH and identify LOH at D10S1765 and D6S1581 as novel blood-based biomarkers for ovarian cancer, being relevant for therapy-monitoring.

【 授权许可】

CC BY   
© Kuhlmann et al.; licensee BioMed Central Ltd. 2012