Detection of HER2 amplification in breast carcinomas: comparison of multiplex ligation-dependent probe amplification (MLPA) and fluorescence in situ hybridization (FISH) combined with automated spot counting

Abstract. In this study the detection of HER2 gene amplification was evaluated using Fluorescence In Situ Hybridization (FISH; PathVysion) in comparison with Multiplex Ligation-dependent Probe Amplification (MLPA), a PCR based technique. These two methods were evaluated on a series of 46 formalin fixed paraffin embedded breast carcinomas, previously tested for protein overexpression by HercepTest (grouped into Hercep 1+, 2+ and 3+). HER2 gene amplification (ratio 2.0) by FISH was found in 9/10, 10/30 and 0/6 in IHC 3+, 2+ and 1+/0 cases, respectively. Digitalized automated spot counting performed with recently developed CW4000 CytoFISH software was 100% concordant with manual FISH scoring. Using MLPA 18/46 samples showed a clear HER2 amplification. Comparing MLPA and IHC showed the same results as for FISH and IHC. All but one FISH positive cases (18/19) were confirmed by MLPA for the presence of the gene amplification. The overall concordance of detection of Her2 gene amplification by FISH and MLPA was 98% (45/46). Furthermore, both the level of amplification and equivocal results correlated well between both methods. In conclusion, MLPA is a reliable and reproducible technique and can be used as an either alternative or additional test to determine HER2 status in breast carcinomas

Positional cloning of the Fanconi anaemia group A gene

The Fanconi anaemia/Breast cancer consortium* Fanconi anaemia (FA) is an autosomal recessive disorder associated with progressive bone-marrow failure, a variety of congenital abnormalities, and predisposition to acute myeloid leukaemia1. Cells from FA patients show increased sensitivity to bifunctional DNA crosslinking agents such as diepoxybutane and mitomycin C, with characteristic chromosome breakage2. FA is genetically heterogeneous, at least five different complementation groups (FA-A to FA-E) having been described3,4. The gene for group C (FAC) was cloned by functional complementation and mapped to chromosome 9q22.3 (refs 3, 5), but the genes for the other complementation groups have not yet been identified. The group A gene (FAA) has recently been mapped to chromosome 16q24.3 by linkage analysis6, and accounts for 60−65% of FA cases7,8. We narrowed the candidate region by linkage and allelic association analysis, and have isolated a gene that is mutated in FA-A patients. The gene encodes a protein of 1,455 amino acids that has no significant homology to any other known proteins, and may therefore represent a new class of genes associated with the prevention or repair of DNA damage.Sinoula Apostolou, Scott A. Whitmore, Joanna Crawford, Gregory Lennon, Grant R. Sutherland, David F. Callen, Leonarda lanzano, Maria Savino, Maria D'Apolito, Angelo Notarangeio, Elena Memeo, Maria Rosaria Piemontese, Leopoldo Zelante, Anna Savoia, Rachel A. Gibson, Alex J. Tipping, Neil V. Morgan, Sheila Hassock, Stander Jansen, Thomy J. de Ravel, Carola Van Berkell, Jan C. Pronk, Douglas F. Easton, Christopher G. Mathew, Orna Levran, Peter C. Verlander, Sat Dev Batish, Tamar Erlich, Arleen D. Auerbach, Anne-Marie Cleton-Jansen, Elna W. Moerland, Cees J. Cornelisse, Norman A. Doggett, Larry L. Deaven & Robert K. Moyzishttp://www.ncbi.nlm.nih.gov/pubmed/889656