1. ¹Department of Epidemiology & International Public Health, University of Bielefeld, Bielefeld, Germany
2. ²Department of Epidemiology, Social Medicine and Health System Research, Hannover Medical School, Hannover, Germany
3. ³Institute of Cell and Molecular Pathology, Hannover Medical School, Hannover, Germany

Correspondence: Dr A Gerhardus, Department of Epidemiology & International Public Health, University of Bielefeld, PO Box 10 01 31, D-33501 Bielefeld, Germany. Tel: +49 521 106 4668; Fax: 49 521 106 6465; E-mail: ansgar.gerhardus@uni-bielefeld.de

⁴These authors contributed equally to this manuscript.

Received 28 July 2006; Revised 23 January 2007; Accepted 7 February 2007; Published online 7 March 2007.

Abstract

As sequence analysis for BRCA1 and BRCA2 mutations is both time- and cost-intensive, current strategies often include scanning techniques to identify fragments containing genetic sequence alterations. However, a systematic assessment of the diagnostic accuracy has been lacking so far. Here, we report on a systematic review to assess the internal and external validity of current scanning techniques. Inclusion criteria were: controlled design, investigators blinded, and tests suitable as a scanning tool for the whole genes BRCA1 and BRCA2. Outcome parameters were sensitivity, specificity, and positive and negative predictive values compared to direct sequencing. Out of 3816 publications, 10 studies reporting on 12 methods met our inclusion criteria. The internal and external validity of most of these studies was limited. Sensitivities were reported to be 100% for enzymatic mutation detection (EMD), multiple-dye cleavase fragment length polymorphism (MD-CFLP), fluorescence-based conformation-sensitive gel electrophoresis (F-CSGE), RNA-based sequencing, restriction endonuclease fingerprinting-single strand conformation polymorphism (REF-SSCP), stop codon (SC) assay, and denaturing high-performance liquid chromatography (DHPLC). Sensitivity was 50–96% for SSCP, 88–91% for two-dimensional gene scanning (TDGS), 76% for conformation-sensitive gel electrophoresis (CSGE), 75% for protein truncation test (PTT), and 58% for micronucleus test (MNT). Specificities close to 100% were reported, except for MNT. PTT and SC assay are only able to detect truncating mutations. Most studies were designed to introduce new experimental approaches or modifications of established methods and require further evaluation. F-CSGE, REF-SSCP, RNA-based sequencing, EMD, and MD-CFLP will need further evaluation before their use in a routine setting can be considered. SSCP, MNT, PTT, CSGE, and TDGS cannot be recommended because of their low sensitivity. DHPLC outperforms all other methods studied. However, none of the four studies evaluating DHPLC was performed on BRCA2.