Abstract LB-61: Comparative study of different diagnostic techniques (AI, MLPA, FISH) in breast cancer patients with 1q25.3 alterations

Abstract

Abstract Background: Breast cancer is the most frequently diagnosed malignancy among women and is the leading cause of cancer related death worldwide. Molecular genetic studies have revealed many subgroups of breast cancer within which the genomic alterations affecting chromosome arm 1q are considered to be an early event in breast carcinogenesis and are correlated with favorable prognosis for the patients. We have found a high percentage of concordance between the AI and MLPA assays pointing towards gain of the 1q25.3 region in breast cancer. Aims: Our main objective was to compare the sensitivity and specificity of AI and synthetic probe-based MLPA with other cytogenetic method (FISH) in breast cancer patients with or without previously confirmed alterations within 1q25.3. Methods: FISH was performed on formalin-fixed paraffin-embedded tumor material in order to verify previous findings and assess the level of genetic alterations of 1q25.3 in breast cancer. The 1q25.3 test and 1p35 reference probes labeled with different fluorochromes were utilized for analysis. Results: A total of 70 nuclei from each breast cancer case were examined and scored for the percentage of 1q25.3 alterations. The non-tumorigenic nuclei obtained from healthy individuals served as adequate cut-off for the 1q25.3-specific changes. The overall FISH results are consistent with results obtained from previous analysis in the majority of analysed cases. Furthermore, FISH resolved the level of 1q25.3 alterations in few cases that were uncertain by AI and MLPA analysis. Conclusion: This study shows that both AI and MLPA assays are able to map regions of copy number changes in the cancer genome and are in concordance with molecular cytogenetics. These three techniques proved to be an efficient tool for diagnosis of 1q25.3 alterations, however, confusing results in AI and MLPA analysis might be obtained while using non-microdissected tumor DNA as a template. Citation Format: {Authors}. {Abstract title} [abstract]. In: Proceedings of the 101st Annual Meeting of the American Association for Cancer Research; 2010 Apr 17-21; Washington, DC. Philadelphia (PA): AACR; Cancer Res 2010;70(8 Suppl):Abstract nr LB-61.