1. Non-hotspot PIK3CA mutations are more frequent in CLOVES than in common or combined lymphatic malformations
- Author
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Pascal Brouillard, Elodie Fastré, Annamaria Weitz-Tuoretmaa, Louise Pasquesoone, Catheline Vilain, Nassim Homayun Sepehr, Anne Dompmartin, Sandra Schmitz, Angela Queisser, Philippe Clapuyt, Raphaël Helaers, Laurence M. Boon, Matthieu J. Schlögel, Frank Hammer, Simon Boutry, Miikka Vikkula, Jussi Laranne, Tampere University, Clinical Medicine, Department of Otology and Oral Diseases, and UCL - SSS/DDUV/GEHU - Génétique
- Subjects
0301 basic medicine ,Pathology ,Klippel-Trenaunay-Weber Syndrome ,Génétique clinique ,Vascular Malformations ,Epidemiology ,Pharmacologie ,medicine.disease_cause ,Gene ,PI3K ,law.invention ,0302 clinical medicine ,law ,Genotype ,Pharmacology (medical) ,Lymphatic malformation ,Genetics (clinical) ,Polymerase chain reaction ,Allele ,Mutation ,General Medicine ,Sciences bio-médicales et agricoles ,Lymphatic Endothelium ,Lymphatic system ,030220 oncology & carcinogenesis ,Medicine ,Lipoma ,medicine.medical_specialty ,Class I Phosphatidylinositol 3-Kinases ,government.form_of_government ,03 medical and health sciences ,medicine ,Humans ,Somatic ,Genotyping ,Isolated ,Theragnostic ,Lymphatic Abnormalities ,business.industry ,Research ,Endothelial Cells ,Frequency ,030104 developmental biology ,Overgrowth syndrome ,government ,1182 Biochemistry, cell and molecular biology ,3111 Biomedicine ,business - Abstract
Background: Theragnostic management, treatment according to precise pathological molecular targets, requests to unravel patients’ genotypes. We used targeted next-generation sequencing (NGS) or digital droplet polymerase chain reaction (ddPCR) to screen for somatic PIK3CA mutations on DNA extracted from resected lesional tissue or lymphatic endothelial cells (LECs) isolated from lesions. Our cohort (n = 143) was composed of unrelated patients suffering from a common lymphatic malformation (LM), a combined lymphatic malformation [lymphatico-venous malformation (LVM), capillaro-lymphatic malformation (CLM), capillaro-lymphatico-venous malformation (CLVM)], or a syndrome [CLVM with hypertrophy (Klippel-Trenaunay-Weber syndrome, KTS), congenital lipomatous overgrowth-vascular malformations-epidermal nevi -syndrome (CLOVES), unclassified PIK3CA-related overgrowth syndrome (PROS) or unclassified vascular (lymphatic) anomaly syndrome (UVA)]. Results: We identified a somatic PIK3CA mutation in resected lesions of 108 out of 143 patients (75.5%). The frequency of the variant allele ranged from 0.54 to 25.33% in tissues, and up to 47% in isolated endothelial cells. We detected a statistically significant difference in the distribution of mutations between patients with common and combined LM compared to the syndromes, but not with KTS. Moreover, the variant allele frequency was higher in the syndromes. Conclusions: Most patients with an common or combined lymphatic malformation with or without overgrowth harbour a somatic PIK3CA mutation. However, in about a quarter of patients, no such mutation was detected, suggesting the existence of (an)other cause(s). We detected a hotspot mutation more frequently in common and combined LMs compared to syndromic cases (CLOVES and PROS). Diagnostic genotyping should thus not be limited to PIK3CA hotspot mutations. Moreover, the higher mutant allele frequency in syndromes suggests a wider distribution in patients’ tissues, facilitating detection. Clinical trials have demonstrated efficacy of Sirolimus and Alpelisib in treating patients with an LM or PROS. Genotyping might lead to an increase in efficacy, as treatments could be more targeted, and responses could vary depending on presence and type of PIK3CA-mutation., SCOPUS: ar.j, info:eu-repo/semantics/published
- Published
- 2021