on behalf of the 100,000 Genomes Project Purpose: Fresh-frozen (FF) tissue is the optimal source of DNA for whole-genome sequencing (WGS) of cancer patients. However, it is not always available, limiting the widespread application of WGS in clinical practice. We explored the viability of using formalin-fixed, paraffin-embedded (FFPE) tissues, available routinely for cancer patients, as a source of DNA for clinical WGS. Methods:We conducted a prospective study using DNAs from matched FF, FFPE, and peripheral blood germ-line specimens collected from 52 cancer patients (156 samples) following routine diagnostic protocols. We compared somatic variants detected in FFPE and matching FF samples. Results:We found the single-nucleotide variant agreement reached 71% across the genome and somatic copy-number alterations (CNAs) detection from FFPE samples was suboptimal (0.44 median correlation with FF) due to nonuniform coverage. CNA detection was improved significantly with lower reverse crosslinking temperature in FFPE DNA extraction (80°C or 65°C depending on the methods). Our final data showed somatic variant detection from FFPE for clinical decision making is possible. We detected 98% of clinically actionable variants (including 30/31 CNAs). Conclusion:We present the first prospective WGS study of cancer patients using FFPE specimens collected in a routine clinical environment proving WGS can be applied in the clinic.Genet Med advance online publication 1 February 2018

Key Points• Targeted NGS of relapsed/ refractory CLL reveals a high incidence of concurrent mutations that mostly affect the TP53, ATM, and SF3B1 genes.• Concurrent mutations of the TP53, ATM, and/or SF3B1 genes confer short survival in patients with relapsed/ refractory CLL.Although TP53, NOTCH1, and SF3B1 mutations may impair prognosis of patients with chronic lymphocytic leukemia (CLL) receiving frontline therapy, the impact of these mutations or any other, alone or in combination, remains unclear at relapse. The genome of 114 relapsed/refractory patients included in prospective trials was screened using targeted next-generation sequencing of the TP53, SF3B1, ATM, NOTCH1, XPO1, SAMHD1, MED12, BIRC3, and MYD88 genes. We performed clustering according to both number and combinations of recurrent gene mutations. The number of genes affected by mutation was ‡2, 1, and 0 in 43 (38%), 49 (43%), and 22 (19%) respectively. Recurrent combinations of ‡2 mutations of TP53, SF3B1, and ATM were found in 22 (19%) patients. This multiplehit profile was associated with a median progression-free survival of 12 months compared with 22.5 months in the remaining patients (P 5 .003). Concurrent gene mutations are frequent in patients with relapsed/refractory CLL and are associated with worse outcome. (Blood. 2015;126(18):2110-2117 IntroductionChronic lymphocytic leukemia (CLL) is characterized by its unique immunophenotype of CD19sIg dim expressing clonal mature B cells and also by a highly variable clinical course. With the emergence of new classes of drugs such as the inhibitor of phosphatidylinositol 3-kinase, idelalisib, 1 and the irreversible inhibitor of Bruton tyrosine kinase, ibrutinib, 2 available treatment options have increased significantly and allow us to begin to develop models of treatment stratification. Over the last 3 years, the CLL genome has been thoroughly characterized by next-generation sequencing (NGS).3 Pioneer reports using this approach unraveled somatic mutations recurrently targeting multiple genes, among which TP53, SF3B1, NOTCH1, MYD88, and ATM were the most frequent. [4][5][6][7][8][9] Large retrospective studies in untreated patients from historical cohorts have recently shown the adverse prognostic impact of the TP53, NOTCH1, and SF3B1 mutations on time to treatment and overall survival (OS). [10][11][12] In addition, mutations in these genes may also be associated with poor progression-free survival (PFS) in frontline patients treated in prospective trials. 13,14 Conversely, the pejorative impact of TP53, SF3B1, and NOTCH1 mutations on the clinical outcome of patients with relapsed/ refractory (R/R) CLL is controversial. [15][16][17] Compared with untreated CLL, relapse, as advanced disease, may be associated with a high level of genomic diversification. 9,18 This process might result in For personal use only. on May 11, 2018. by guest www.bloodjournal.org From accumulation and co-occurrence of these or other genomic events leading to interactions that could be of prognostic relevance. Here, w...

Chronic lymphocytic leukaemia (CLL) consists of two biologically and clinically distinct subtypes defined by the abundance of somatic hypermutation (SHM) affecting the Ig variable heavy-chain locus (IgHV). The molecular mechanisms underlying these subtypes are incompletely understood. Here, we present a comprehensive whole-genome sequencing analysis of somatically acquired genetic events from 46 CLL patients, including a systematic comparison of coding and non-coding single-nucleotide variants, copy number variants and structural variants, regions of kataegis and mutation signatures between IgHVmut and IgHVunmut subtypes. We demonstrate that one-quarter of non-coding mutations in regions of kataegis outside the Ig loci are located in genes relevant to CLL. We show that non-coding mutations in ATM may negatively impact on ATM expression and find non-coding and regulatory region mutations in TCL1A, and in IgHVunmut CLL in IKZF3, SAMHD1,PAX5 and BIRC3. Finally, we show that IgHVunmut CLL is dominated by coding mutations in driver genes and an aging signature, whereas IgHVmut CLL has a high incidence of promoter and enhancer mutations caused by aberrant activation-induced cytidine deaminase activity. Taken together, our data support the hypothesis that differences in clinical outcome and biological characteristics between the two subgroups might reflect differences in mutation distribution, incidence and distinct underlying mutagenic mechanisms.

The transformation of chronic lymphocytic leukemia (CLL) to high-grade B-cell lymphoma is known as Richter's Syndrome (RS) and it is a rare event with dismal prognosis. In this study, we conducted whole genome sequencing (WGS) of paired circulating CLL (PB-CLL) and RS biopsies (tissue-RS) from 17 clinical trial (CHOP-O) patients. We found that tissue-RS was enriched for mutations in poor-risk CLL drivers and genes in the DNA damage response (DDR) pathway. In addition, we identified genomic aberrations not previously implicated in RS, including the protein tyrosine phosphatase receptor (PTPRD) and tumour necrosis factor receptor associated factor three (TRAF3). In the non-coding genome, we discovered AID-related and unrelated kataegis in tissue-RS affecting regulatory regions of key immune regulatory genes. These include BTG2, CXCR4, NFATC1, PAX5, NOTCH-1, SLC44A5, FCRL3, SELL, TNIP2 andTRIM13. Furthermore, differences between the global mutation signatures of pairs of PB-CLL and tissue-RS samples implicate DDR as the dominant mechanism driving transformation. Pathway-based clonal de-convolution analysis showed that genes in the MAPK and DDR pathways demonstrate high clonal expansion probability. Direct comparison of nodal-CLL and tissue-RS pairs from an independent cohort confirmed differential expression of the same pathways by RNA expression profiling. Our integrated analysis of WGS and RNA expression data significantly extends previous targeted approaches, which were limited by the lack of germline samples, and it facilitates the identification of novel genomic correlates implicated in RS transformation, which could be targeted therapeutically. Our results inform the future selection of investigative agents for a UK clinical platform study (NCT03899337).