Genomic profiling of multiple breast cancer reveals inter-lesional heterogeneity
Menée à partir d'échantillons tumoraux prélevés sur 21 patientes atteintes d'un cancer du sein à tumeurs multiples, cette étude met en évidence, à l'aide d'une technique de séquençage de nouvelle génération utilisant un panel de 170 gènes, des hétérogénéités génomiques entre les lésions tumorales d'une même personne
Background : Multiplicity in breast cancer is common. Studies on multiple breast cancers have revealed high concordance in biomarker status among individual lesions. However, genomic differences among multiple lesions are not well-established. We aimed to investigate the potential genomic heterogeneity of multiple breast cancer.
Methods : Twenty-one patients with radiologically and histologically evident multiple breast cancer with similar histology were included. Two lesions from each of the 21 patients were selected, and biomarker status was evaluated for each lesion. Capture-based targeted next-generation sequencing was performed using a cancer gene panel consisting of 170 genes.
Results : We identified discordance in intrinsic subtype in 2 (10%) of the 21 patients. Pathogenic mutations were detected in 13 of the 21 patients, of whom 11 shared oncogenic variants in the two lesions. The remaining two patients yielded different mutation results for TP53, ATM, and PIK3CA. Difference in copy number alteration was observed in 7 (33%) of the 21 patients including ERBB2 (n = 2), FGFR1 (n = 2), and FGFR2 (n = 1) genes.
Conclusion : Despite similar histologic features of the individual lesions, inter-lesional genomic difference was identified in more than one-third of the patients. Inter-lesional genomic heterogeneity needs to be considered when performing a genomic test in multiple breast cancers.
British Journal of Cancer , résumé, 2020