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William J. Gradishar, MD, FACP, FASCO
William J. Gradishar, MD, FACP, FASCO
Posted: Monday, April 8, 2024
Given the limited knowledge regarding the molecular framework of phyllodes tumors, which usually develop in the connective tissue of the breast, current investigative efforts have been directed at providing insight that may guide treatment strategies for the affected patient population. Published in The Journal of Pathology, the findings of a histopathologic analysis of these rare tumors revealed alterations in DNA methylation that may assist with risk stratification, improve diagnostic accuracy, and distinguish these tumors from metaplastic breast cancers—suggested Sandra O’Toole, PhD, of the Garvan Institute of Medical Research, Sydney, New South Wales, Australia, and colleagues.
From 2007 to 2017, a total of 33 patients with cellular fibroepithelial lesions and metaplastic breast cancer were recruited for the study. All patients had their tumors excised and were stratified based on World Health Organization categories: benign (n = 2), borderline (n = 9), malignant phyllodes tumors (n = 18), fibroadenomas (n = 2), and metaplastic breast cancer (n = 2). DNA samples were collected and analyzed to quantify the extent of methylation.
When the investigators compared phyllodes tumors with normal breast tissue and histopathologically similar tumors, phyllodes tumors demonstrated a unique methylome. Increased methylation was observed in genes essential to epithelial-mesenchymal transition and KRAS signaling pathways. In addition, evidence of hypermethylation was reported in 53 regions of malignant phyllodes tumors compared with nonmalignant tumors. The most notable hypermethylated segment was the HSD17B8 CpG island promoter, which simultaneously showed a reduced extent of expression in fibroblast cells.
“The next step for the clinical translation would be a multicenter study for phyllodes tumor biomarker validation,” explained Dr. O’Toole and colleagues.
Disclosure: The study authors reported no conflicts of interest.
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