Application of targeted next generation sequencing for the mutational profiling of patients with acute lymphoblastic leukemia

lt b gt Uvod: lt /b gt Akutna limfoblastna leukemija (ALL) je najčešće maligno oboljenje kod dece, dok je kod odraslih njena učestalost mnogo niža. U današnjoj kliničkoj praksi kao najvažnije metode stratifikacije pacijenata u određene grupe rizika koriste se metode identifikacije citogenetičkih aberacija i malog broja molekulanih markera. Tehnologija sekvenciranja nove generacije (SNG) obezbeđuje veliku količinu podataka koji doprinose razjašnjavanju mutacionog profila dečje (dALL) i adultne ALL (aALL). lt b gt Metode: lt /b gt Uzorci DNK iz 34 dALL i aALL pacijenata analizirani su primenom SNG ciljanog sekvenciranja ("TruSeq Amplicon Cancer Panel - TSACP") kojim se sekvenciraju "hotspot" mutacije u 48 gena povezanih sa kancerom. lt b gt Rezultati: lt /b gt Identifikovano je ukupno 330 varijanti u kodirajućim regionima, od kojih je samo 95 njih za posledicu imalo potencijalnu promenu u proteinu. Posmatrano kod pojedinačnih pacijenata, detektovane mutacije su pretežno remetile Ras/RTK signalni put (STK11, KIT, MET, NRAS, KRAS, PTEN). Pored toga, identifikovano je 5 pacijenata sa istom mutacijom u HNF1A genu, koja je uzrokovala poremećaje u Wnt i Notch signalnom putu. Kod dva pa cijenta otkrivene su varijante u NOTCH1 genu. Nije detektovano istovremeno prisustvo varijanti u HNF1A i NOTCH1 genu, dok su geni uključeni u Ras/RTK signalni put pokazali tendenciju ka akumuliranju mutacija. lt b gt Zaključak: lt /b gt Naši rezultati pokazuju da ALL sadrži Mali broj mutacija, bez značajnih razlika između dALL i aALL (medijana po pacijentu 2 odnosno 3). Detektovane mutacije izazivaju poremećaje u nekoliko ključnih signalnih puteva, prvenstveno Ras/RTK kaskade. Ova studija doprinosi ukupnom znanju o mutacionom profilu ALL, što vodi ka boljem razumijevanju molekularne osnove ovog oboljenja.lt b gt Background: lt /b gt Acute lymphoblastic leukemia (ALL) is the most common cancer in children, whereas it is less common in adults. Identification of cytogenetic aberrations and a small number of molecular abnormalities are still the most important risk and therapy stratification methods in clinical practice today. Next generation sequencing (NGS) technology provides a large amount of data contributing to elucidation of mutational landscape of childhood (cALL) and adult ALL (aALL). lt b gt Methods: lt /b gt We analyzed DNA samples from 34 cALL and aALL patients, using NGS targeted sequencing TruSeq Amplicon - Cancer Panel (TSACP) which targets mutational hotspots in 48 cancer related genes. lt b gt Results: lt /b gt We identified a total of 330 variants in the coding regions, out of which only 95 were potentially protein-changing. Observed in individual patients, detected mutations predominantly disrupted Ras/RTK pathway (STK11, KIT, MET, NRAS, KRAS, PTEN). Additionally, we identified 5 patients with the same mutation in HNF1A gene, disrupting both Wnt and Notch signaling pathway. In two patients we detected variants in NOTCH1 gene. HNF1A and NOTCH1 variants were mutually exclusive, while genes involved in Ras/RTK pathway exhibit a tendency of mutation accumulation. lt b gt Conclusions: lt /b gt Our results showed that ALL contains low number of mutations, without significant differences between cALL and aALL (median per patient 2 and 3, respectively). Detected mutations affect few key signaling pathways, primarily Ras/RTK cascade. This study contributes to knowledge of ALL mutational landscape, leading to better understanding of molecular basis of this disease

Parallel targeted next generation sequencing of childhood and adult acute myeloid leukemia patients reveals uniform genomic profile of the disease

The age-specific differences in the genetic mechanisms of myeloid leukemogenesis have been observed and studied previously. However, NGS technology has provided a possibility to obtain a large amount of mutation data. We analyzed DNA samples from 20 childhood (cAML) and 20 adult AML (aAML) patients, using NGS targeted sequencing. The average coverage of high-quality sequences was 2981 x per amplicon. A total of 412 (207 cAML, 205 aAML) variants in the coding regions were detected; out of which, only 122 (62 cAML and 60 aAML) were potentially protein-changing. Our results confirmed that AML contains small number of genetic alterations (median 3 mutations/patient in both groups). The prevalence of the most frequent single gene AML associated mutations differed in cAML and aAML patient cohorts: IDH1 (0 % cAML, 5 % aAML), IDH2 (0 % cAML, 10 % aAML), NPM1 (10 % cAML, 35 % aAML). Additionally, potentially protein-changing variants were found in tyrosine kinase genes or genes encoding tyrosine kinase associated proteins (JAK3, ABL1, GNAQ, and EGFR) in cAML, while among aAML, the prevalence is directed towards variants in the methylation and histone modifying genes (IDH1, IDH2, and SMARCB1). Besides uniform genomic profile of AML, specific genetic characteristic was exclusively detected in cAML and aAML

Gene Mutation Profiles in Primary Diffuse Large B Cell Lymphoma of Central Nervous System: Next Generation Sequencing Analyses

The existence of a potential primary central nervous system lymphoma-specific genomic signature that differs from the systemic form of diffuse large B cell lymphoma (DLBCL) has been suggested, but is still controversial. We investigated 19 patients with primary DLBCL of central nervous system (DLBCL CNS) using the TruSeq Amplicon Cancer Panel (TSACP) for 48 cancer-related genes. Next generation sequencing (NGS) analyses have revealed that over 80% of potentially protein-changing mutations were located in eight genes (CTNNB1, PIK3CA, PTEN, ATM, KRAS, PTPN11, TP53 and JAK3), pointing to the potential role of these genes in lymphomagenesis. TP53 was the only gene harboring mutations in all 19 patients. In addition, the presence of mutated TP53 and ATM genes correlated with a higher total number of mutations in other analyzed genes. Furthermore, the presence of mutated ATM correlated with poorer event-free survival (EFS) (p = 0.036). The presence of the mutated SMO gene correlated with earlier disease relapse (p = 0.023), inferior event-free survival (p = 0.011) and overall survival (OS) (p = 0.017), while mutations in the PTEN gene were associated with inferior OS (p = 0.048). Our findings suggest that the TP53 and ATM genes could be involved in the molecular pathophysiology of primary DLBCL CNS, whereas mutations in the PTEN and SMO genes could affect survival regardless of the initial treatment approach