TOPBP1 missense variant Arg309Cys and breast cancer in a German hospital-based case-control study

The DNA double strand break repair gene TOPBP1 has been suggested as a breast cancer susceptibility gene and a missense variant Arg309Cys was observed at elevated frequency in familial breast cancer cases compared to healthy controls from Finland. We found the Arg309Cys allele at a 13% carrier frequency in a hospital-based series of 1064 German breast cancer patients and at a 14% carrier frequency in 1014 population controls (OR 0.89, 95%CI 0.69-1.15; p = 0.4). Arg309Cys carriers were not enriched among patients with a family history of breast cancer (OR = 0.87, 95%CI 0.53-1.43, p = 0.6) and were slightly underrepresented in patients with bilateral disease (OR = 0.49, 95%CI = 0.24-0.99; p = 0.047). In the latter group, the mean age at diagnosis was 62 years in carriers and 54 years in non-carriers (p = 0.004). We conclude that there is no evidence for the TOPBP1*Arg309Cys variant to confer an increased risk for breast cancer in the German population

Mutation analysis of the MDM4 gene in German breast cancer patients

<p>Abstract</p> <p>Background</p> <p>MDM4 is a negative regulator of p53 and cooperates with MDM2 in the cellular response to DNA damage. It is unknown, however, whether <it>MDM4 </it>gene alterations play some role in the inherited component of breast cancer susceptibility.</p> <p>Methods</p> <p>We sequenced the whole <it>MDM4 </it>coding region and flanking untranslated regions in genomic DNA samples obtained from 40 German patients with familial breast cancer. Selected variants were subsequently screened by RFLP-based assays in an extended set of breast cancer cases and controls.</p> <p>Results</p> <p>Our resequencing study uncovered two <it>MDM4 </it>coding variants in 4/40 patients. Three patients carried a silent substitution at codon 74 that was linked with another rare variant in the 5'UTR. No association of this allele with breast cancer was found in a subsequent screening of 133 patients with bilateral breast cancer and 136 controls. The fourth patient was heterozygous for the missense substitution D153G which is located in a less conserved region of the MDM4 protein but may affect a predicted phosphorylation site. The D153G substitution only partially segregated with breast cancer in the family and was not identified on additional 680 chromosomes screened.</p> <p>Conclusion</p> <p>This study did not reveal clearly pathogenic mutations although it uncovered two new unclassified variants at a low frequency. We conclude that there is no evidence for a major role of <it>MDM4 </it>coding variants in the inherited susceptibility towards breast cancer in German patients.</p

Fine-Scale Mapping of the 4q24 Locus Identifies Two Independent Loci Associated with Breast Cancer Risk

Background: A recent association study identified a common variant (rs9790517) at 4q24 to be associated with breast cancer risk. Independent association signals and potential functional variants in this locus have not been explored. Methods: We conducted a fine-mapping analysis in 55,540 breast cancer cases and 51,168 controls from the Breast Cancer Association Consortium. Results: Conditional analyses identified two independent association signals among women of European ancestry, represented by rs9790517 [conditional P = 2.51 × 10−4; OR, 1.04; 95% confidence interval (CI), 1.02–1.07] and rs77928427 (P = 1.86 × 10−4; OR, 1.04; 95% CI, 1.02–1.07). Functional annotation using data from the Encyclopedia of DNA Elements (ENCODE) project revealed two putative functional variants, rs62331150 and rs73838678 in linkage disequilibrium (LD) with rs9790517 (r2 ≥ 0.90) residing in the active promoter or enhancer, respectively, of the nearest gene, TET2. Both variants are located in DNase I hypersensitivity and transcription factor–binding sites. Using data from both The Cancer Genome Atlas (TCGA) and Molecular Taxonomy of Breast Cancer International Consortium (METABRIC), we showed that rs62331150 was associated with level of expression of TET2 in breast normal and tumor tissue. Conclusion: Our study identified two independent association signals at 4q24 in relation to breast cancer risk and suggested that observed association in this locus may be mediated through the regulation of TET2. Impact: Fine-mapping study with large sample size warranted for identification of independent loci for breast cancer risk

Comparison of 6q25 Breast Cancer Hits from Asian and European Genome Wide Association Studies in the Breast Cancer Association Consortium (BCAC)

Peer reviewe

Langerhans Cell Histiocytosis of the Cranial Base: Is Low-Dose Radiotherapy Effective?

Introduction. Langerhans cell histiocytosis (LCH) is a rare disease of unknown etiology with different clinical features. A standardised treatment has not been established so far. Case Report. We report a case of a 28-year-old patient who initially presented with hypesthesia of the fifth cranial nerve and pain of the left ear. Diagnosis showed a tumour localised in the cranial base with a maximum diameter of 4.1 cm. The diagnosis of LCH was confirmed histologically by biopsy. Diagnostic workup verified the cranial lesion as the sole manifestation of LCH. A total dose of 9 Gy (single dose 1.8 Gy) was delivered. The symptoms dissolved completely within 6 months after radiation; repeated CT and MRI scans revealed a reduction in size of the lesion and a remineralisation of the bone. After a followup of 13 years the patient remains free of symptoms without relapse or any side effects from therapy. Discussion. Due to the indolent course of the disease with a high rate of spontaneous remissions the choice of treatment strongly depends on the individual clinical situation. In the presented case low-dose radiotherapy was sufficient to obtain long-term local control in a region with critical structures and tissues