Rivas-Delgado Alfredo, Nadeu Ferran, Andrade-Campos Marcio, López Cristina, Enjuanes Anna, Mozas Pablo, Frigola Gerard, Colomo Luis, Sanchez-Gonzalez Blanca, Villamor Neus, Beà Sílvia, Campo Elías, Salar Antonio, Giné Eva, López-Guillermo Armando, Bellosillo Beatriz
Hematology Department, Hospital Clínic de Barcelona, 08036 Barcelona, Spain.
Institut d'Investigacions Biomèdiques August Pi i Sunyer (IDIBAPS), 08036 Barcelona, Spain.
Diagnostics (Basel). 2022 Jun 28;12(7):1575. doi: 10.3390/diagnostics12071575.
High-throughput sequencing of cell-free DNA (cfDNA) has emerged as a promising noninvasive approach in lymphomas, being particularly useful when a biopsy specimen is not available for molecular analysis, as it frequently occurs in primary mediastinal large B-cell lymphoma (PMBL). We used cfDNA for genomic characterization in 20 PMBL patients by means of a custom NGS panel for gene mutations and low-pass whole-genome sequencing (WGS) for copy number analysis (CNA) in a real-life setting. Appropriate cfDNA to perform the analyses was obtained in 18/20 cases. The sensitivity of cfDNA to detect the mutations present in paired FFPE samples was 69% (95% CI: 60-78%). The mutational landscape found in cfDNA samples was highly consistent with that of the tissue, with the most frequently mutated genes being (61%), (61%), (44%), (44%), (39%), (33%), and (33%). Overall, we observed a 75% concordance to detect CNA gains/losses between DNA microarray and low-pass WGS. The sensitivity of low-pass WGS was remarkably higher for clonal CNA (18/20, 90%) compared to subclonal alterations identified by DNA microarray. No significant associations between cfDNA amount and tumor burden or outcome were found. cfDNA is an excellent alternative source for the accurate genetic characterization of PMBL cases.
游离DNA（cfDNA）的高通量测序已成为淋巴瘤中一种有前景的非侵入性方法，当无法获得活检标本进行分子分析时，该方法尤其有用，原发性纵隔大B细胞淋巴瘤（PMBL）经常出现这种情况。在实际应用中，我们通过定制的NGS基因panel对20例PMBL患者的cfDNA进行基因突变分析，并通过低深度全基因组测序（WGS）进行拷贝数分析（CNA），以实现基因组特征分析。20例中有18例获得了用于分析的合适cfDNA。cfDNA检测配对FFPE样本中存在的突变的灵敏度为69%（95%CI：60-78%）。cfDNA样本中发现的突变图谱与组织高度一致，最常发生突变的基因是 （61%）、 （61%）、 （44%）、 （44%）、 （39%）、 （33%）和 （33%）。总体而言，我们观察到DNA微阵列与低深度WGS在检测CNA增加/减少方面的一致性为75%。与DNA微阵列鉴定的亚克隆改变相比，低深度WGS对克隆性CNA的灵敏度显著更高（18/20，90%）。未发现cfDNA量与肿瘤负荷或预后之间存在显著关联。cfDNA是PMBL病例准确基因特征分析的优秀替代来源。
