Background: 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).
Methods: 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.
Results: 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.
Conclusions: 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.
Uvod: 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).
Metode: 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.
Rezultati: 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.
Zaključak: 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.
Keywords: acute lymphoblastic leukemia; next generation sequencing; somatic mutations.
2020 Dragana Janic, Jelena Peric, Teodora Karan-Djurasevic, Tatjana Kostic, Irena Marjanovic, Bojana Stanic, Nadja Pejanovic, Lidija Dokmanovic, Jelena Lazic, Nada Krstovski, Marijana Virijevic, Dragica Tomin, Ana Vidovic, Nada Suvajdzic-Vukovic, Sonja Pavlovic, Natasa Tosic, published by CEON/CEES.