Thilo Dörk’s research while affiliated with Hannover Medical School and other places

The role of germline genetics in adjuvant aromatase inhibitor (AI) treatment efficacy in ER-positive breast cancer is poorly understood. We employed a two-stage candidate gene approach to examine associations between survival endpoints and common germline variants in 753 endocrine resistance-related genes. For a discovery cohort, we screened the Breast Cancer Association Consortium database (n ≥ 90,000 cases) and retrieved 2789 AI-treated patients. Cox model-based analysis revealed 125 variants associated with overall, distant relapse-free, and relapse-free survival (p-value ≤ 1E-04). In validation analysis using five independent cohorts (n = 8857), none of the six selected candidates representing major linkage blocks at CELA2B/CASP9, NR1I2/GSK3B, LRP1B, and MIR143HG (CARMN) were validated. We discuss potential reasons for the failed validation and replication of published findings, including study/treatment heterogeneity and other limitations inherent to genomic treatment outcome studies. For the future, we envision prospective longitudinal studies with sufficiently long follow-up and endpoints that reflect the dynamic nature of endocrine resistance.

Rare, germline loss-of-function variants in a handful of DNA repair genes are associated with epithelial ovarian cancer. The aim of this study was to evaluate the role of rare, coding, loss-of-function variants across the genome in epithelial ovarian cancer. We carried out a gene-by-gene burden test with various histotypes using data from 2573 non-mucinous cases and 13,923 controls. Twelve genes were associated at a False Discovery Rate of less than 0.1 of which seven were the known ovarian cancer susceptibility genes BRCA1 , BRCA2 , BRIP1 , RAD51C , RAD51D, MSH6 and PALB2 . The other five genes were OR2T35, HELB, MYO1A and GABRP which were associated with non-high-grade serous ovarian cancer and MIGA1 which was associated with high-grade serous ovarian cancer. Further support for the association of HELB association comes from the observation that loss-of-function variants in HELB are associated with age at natural menopause and Mendelian randomisation analysis shows an association between genetically predicted age at natural menopause and endometrioid ovarian cancer, but not high-grade serous ovarian cancer.

Preeclampsia is a pregnancy specific hypertensive disorder and is associated with an increased postpartum risk of cardiovascular morbidity for both women and their offspring. Previous studies have indicated that cord blood endothelial colony forming cells (ECFCs) are dysfunctional in preeclampsia. The specific mechanisms are not yet fully understood but dysregulation of alternative splicing has been proposed as one of the pathogenic pathways. In order to identify specific targets of alternative splicing in fetal ECFCs, we performed transcriptome-wide differential splicing analyses between cord blood ECFCs from preeclamptic (n=16) and normal pregnancies (n=13). Selected splicing events were validated using fragment length analysis and Sanger sequencing. In silico transcriptome-wide differential splicing analysis identified a significantly increased abundance of the CADM1 isoform ENST00000542447 in the preeclamptic cohort (p=0.002), which was confirmed by wet-lab validation. The deleted exon 8 harbours glycosylation sites known to mediate cell-cell adhesion. To investigate the functional impact of alternative splice variants, we induced an in vitro splice switch using antisense morpholino treatment and followed cellular effects using migration and angiogenesis assays in ECFCs from six normal pregnancies. The CADM1 exon 8 skipping converted the normal ECFCs to a preeclampsia-like state characterised by a decreased migration ability (panova=0.005) and decreased tubule length (panova=0.02). We propose aberrant splicing of CADM1 and the resulting changes in the adherence properties of ECFCs as a potential contributor to cardiovascular sequelae in the offspring of preeclamptic pregnancies.

Infection by high‐risk human papillomavirus is known to exacerbate cervical cancer development. The host immune response is crucial in disease regression. Large‐scale genetic association studies for cervical cancer have identified few susceptibility variants, mainly at the human leukocyte antigen locus on chromosome 6. We hypothesized that the host immune response modifies cervical cancer risk and performed three genome‐wide association analyses for HPV16, HPV18 and HPV16/18 seropositivity in 7814, 7924, and 7924 samples from the UK Biobank, followed by validation genotyping in the German Cervigen case‐control series of cervical cancer and dysplasia. In GWAS analyses, we identified two loci associated with HPV16 seropositivity (6p21.32 and 15q26.2), two loci associated with HPV18 seropositivity (5q31.2 and 14q24.3), and one locus for HPV16 and/or HPV18 seropositivity (at 6p21.32). MAGMA gene‐based analysis identified HLA‐DQA1 and HLA‐DQB1 as genome‐wide significant (GWS) genes. In validation genotyping, the genome‐wide significant lead variant at 6p21.32, rs9272293 associated with overall cervical disease (OR = 0.86, p = 0.004, 95% CI = 0.78–0.95, n = 3710) and HPV16 positive invasive cancer (OR = 0.73, p = 0.005, 95% CI = 0.59–0.91, n = 1431). This variant was found to be a robust eQTL for HLA‐DRB1 , HLA‐DQB1‐AS1 , C4B , HLA‐DRB5 , HLA‐DRB6 , HLA‐DQB1 , and HLA‐DPB1 in a series of cervical epithelial tissue samples. We additionally genotyped twenty‐four HPV seropositivity variants below the GWS threshold out of which eleven variants were found to be associated with cervical disease in our cohort, suggesting that further seropositivity variants may determine cervical disease outcome. Our study identifies novel genomic risk loci that associate with HPV type‐specific cervical cancer and dysplasia risk and provides evidence for candidate genes at one of the risk loci.

Background Pathological complete response (pCR) is an established surrogate marker for prognosis in patients with breast cancer (BC) after neoadjuvant chemotherapy. Individualized pCR prediction based on clinical information available at biopsy, particularly immunohistochemical (IHC) markers, may help identify patients who could benefit from preoperative chemotherapy. Methods Data from patients with HER2-negative BC who underwent neoadjuvant chemotherapy from 2002 to 2020 (n = 1166) were used to develop multivariable prediction models to estimate the probability of pCR (pCR-prob). The most precise model identified using cross-validation was implemented in an online calculator and a nomogram. Associations among pCR-prob, prognostic IHC3 distant recurrence and disease-free survival were studied using Cox regression and Kaplan–Meier analyses. The model’s utility was further evaluated in independent external validation cohorts. Results 273 patients (23.4%) achieved a pCR. The most precise model had across-validated area under the curve (AUC) of 0.84, sensitivity of 0.82, and specificity of 0.71. External validation yielded AUCs between 0.75 (95% CI, 0.70–0.81) and 0.83 (95% CI, 0.78–0.87). The higher the pCR-prob, the greater the prognostic impact of pCR status (presence/absence): hazard ratios decreased from 0.55 (95% central range, 0.07–1.77) at 0% to 0.20 (0.11–0.31) at 50% pCR-prob. Combining pCR-prob and IHC3 score further improved the precision of disease-free survival prognosis. Conclusions A pCR prediction model for neoadjuvant therapy decision-making was established. Combining pCR and recurrence prediction allows identification of not only patients who benefit most from neoadjuvant chemotherapy, but also patients with a very unfavorable prognosis for whom alternative treatment strategies should be considered.

Background The 313-variant polygenic risk score (PRS313) provides a promising tool for clinical breast cancer risk prediction. However, evaluation of the PRS313 across different European populations which could influence risk estimation has not been performed. Methods We explored the distribution of PRS313 across European populations using genotype data from 94,072 females without breast cancer diagnosis, of European-ancestry from 21 countries participating in the Breast Cancer Association Consortium (BCAC) and 223,316 females without breast cancer diagnosis from the UK Biobank. The mean PRS was calculated by country in the BCAC dataset and by country of birth in the UK Biobank. We explored different approaches to reduce the observed heterogeneity in the mean PRS across the countries, and investigated the implications of the distribution variability in risk prediction. Results The mean PRS313 differed markedly across European countries, being highest in individuals from Greece and Italy and lowest in individuals from Ireland. Using the overall European PRS313 distribution to define risk categories, leads to overestimation and underestimation of risk in some individuals from these countries. Adjustment for principal components explained most of the observed heterogeneity in the mean PRS. The mean estimates derived when using an empirical Bayes approach were similar to the predicted means after principal component adjustment. Conclusions Our results demonstrate that PRS distribution differs even within European ancestry populations leading to underestimation or overestimation of risk in specific European countries, which could potentially influence clinical management of some individuals if is not appropriately accounted for. Population-specific PRS distributions may be used in breast cancer risk estimation to ensure predicted risks are correctly calibrated across risk categories.

Background: Sudden infant death syndrome (SIDS) is the leading cause of death among infants aged between one month and one year. Altered enzyme activities or expression of acetylcholinesterase (AChE) and butyrylcholinesterase (BChE) have been observed in SIDS patients that might lead to disturbed autonomic function and, together with other risk factors, might trigger SIDS. To explore the contribution of AChE and BChE from a genomic viewpoint, we sought to investigate the association between SIDS and selected single nucleotide polymorphisms (SNPs) in the ACHE and BCHE genes. Methods: In this case-control study, 13 potentially regulatory SNPs were selected from ACHE and BCHE and were genotyped in 201 SIDS cases and 338 controls. The association of SIDS with the 11 successfully genotyped candidate variants was examined using statistical analyses of overall or stratified cases and haplotype analyses. Results: No significant overall associations were observed between SIDS and ACHE and BCHE variants in allele, genotype, and haplotype analyses. In subgroup analyses, eight variants were found to be nominally associated with SIDS, though these associations did not remain statistically significant after correction for multiple comparisons. One haplotype (T-C-G-C-C in rs3495-rs1803274-rs1355538-rs2048493-rs1126680) of BCHE was associated with the female SIDS subgroup (57.3% in controls vs. 46.3% in female SIDS cases, p = 0.010). Conclusions: The selected variants in ACHE and BCHE were not overall associated with SIDS in this study, and thus cannot generally explain the previously reported dysregulation of enzyme activities in SIDS. However, some evidence of association in subgroups and a possible contribution of variants other than those tested here would need to be explored in larger studies.

This study identifies and characterizes a novel type of splicing mutation in RAD50 deficiency, a rare genetic disorder.