Functional ex vivoDNA fibre assay to measure replication dynamics in breast cancer tissue

• DOI: 10.1002/path.6328
• Publication Date: 2024-07-18T08:15:31Z
• Authors: Mengting Chen; Nathalie van den ...; Arkajyoti Bhattac...; Shibo Yu; Bea Rutgers; Rudolf SN Fehrmann; Sander de Haas; Bert van der Vegt; Marcel ATM van Vugt
• Keywords: Ex vivo; Cyclin E1

Abstract Replication stress (RS) is a key trait of cancer cells, and potential actionable target in treatment. Accurate methods to measure RS tumour samples are currently lacking. DNA fibre analysis has been used as common technique cell lines. Here, we investigated on fresh breast specimens correlated replication kinetics known markers genomic alterations. Fresh, treatment‐naïve primary ( n = 74) were subjected ex vivo kinetics. Tumour proliferation was confirmed by EdU incorporation cytokeratin AE1/AE3 (CK) staining. The phospho‐S33‐RPA γH2AX the RS‐inducing proto‐oncogenes Cyclin E1 c‐Myc analysed immunohistochemistry. Copy number variations (CNVs) assessed from genome‐wide single nucleotide polymorphism (SNP) arrays. We found that majority proliferating (EdU‐positive) cells each sample CK‐positive therefore considered be cells. lengths varied largely most samples. median length showed significant inverse correlation with pRPA expression r −0.29, p 0.033) but not or global CNVs this study. Nuclear positive levels 0.481, < 0.0001), while cytoplasmic exhibited an association −0.353, 0.002) 0.318, 0.016). In conclusion, performed feasible. Fibre associated expression. percentage CNVs. © 2024 Author(s). Journal Pathology published John Wiley & Sons Ltd behalf Pathological Society Great Britain Ireland.