Multiplex ligatiofüggő szondaamplifikáció az onkohematológiai kutatásban és diagnosztikában

Absztrakt: A malignus hematológiai betegségek kialakulását, progresszióját, illetve terápiával szemben mutatott rezisztenciáját kísérő genetikai eltéréseket ma már egyre alaposabban ismerjük. A klinikailag releváns abnormalitásoknak a mindennapi diagnosztika keretein belül való célzott kimutatása gyors, megbízható és költséghatékony módszereket igényel. A multiplex ligatiofüggő szondaamplifikáció a genomikus kópiaszám-eltérések vizsgálatának hatékony eszköze, mellyel 55–60 lókusz egyidejűleg analizálható. Az eljárás lehetőséget nyújt prognosztikai és prediktív markerek átfogó felderítésére, így alkalmazása hatékonyan kombinálható a kariotipizálással és fluoreszcencia in situ hibridizációval, melyek jelenleg a legelterjedtebb diagnosztikus technikák citogenetikai aberrációk kimutatására. Ezenkívül a módszer képes a metilációs státusz célzott meghatározására és specifikus mutációk detektálására is, 24 órán belül eredményt szolgáltatva. Az alábbiakban bemutatjuk a multiplex ligatiofüggő szondaamplifikáció technikai hátterét, összefoglaljuk előnyeit és korlátait, valamint megbeszéljük az onkohematológiai kutatásban és diagnosztikában betöltött szerepét. Végezetül, az új generációs szekvenáláshoz kapcsolódó, közelmúltbeli technológiai újítások fényében tárgyaljuk a módszerben rejlő jövőbeli lehetőségeket. Orv Hetil. 2018; 159(15): 583–592. | Abstract: Genetic abnormalities associated with the development, progression and treatment resistance of hematological malignancies are extensively characterized. Rapid, reliable and cost-efficient techniques are needed to screen the clinically relevant aberrations in routine diagnostics. Multiplex ligation-dependent probe amplification is an efficient tool to analyze genomic copy number aberrations at 55–60 different genomic loci. The method allows the profiling of prognostic and predictive markers; thus, it can efficiently be combined with karyotyping and fluorescence in situ hybridization, the most commonly used diagnostic techniques to detect cytogenetic lesions. Furthermore, the method can interrogate methylation status and unravel point mutations at specific sites, providing results in 24 hours. Here, we describe the technical background of multiplex ligation-dependent probe amplification, summarize its advantages and limitations as well as discuss its role in oncohematological diagnostics and research. Finally, future outlook is provided, with emphasis on recent technological advances related to next-generation sequencing. Orv Hetil. 2018; 159(15): 583–592

A CEBPA-mutációk vizsgálata és prognosztikai jelentőségük akut myeloid leukémiában

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Morphologic and molecular analysis of Richter syndrome in chronic lymphocytic leukaemia patients treated with ibrutinib or venetoclax

Richter syndrome (RS) represents the development of high-grade lymphoma in patients with chronic lymphocytic leukaemia (CLL) or small lymphocytic lymphoma (SLL) and presents a diagnostic and therapeutic challenge with an adverse prognosis. The genetic background and morphology of RS in CLL patients treated with chemoimmunotherapy is extensively characterised; however, our knowledge about RS in patients treated with targeted oral therapies should be extended. To understand the morphologic and molecular changes leading to RS in CLL patients treated with the Bruton's tyrosine kinase inhibitor, ibrutinib, and the BCL2 inhibitor, venetoclax, sequential samples from six CLL/SLL patients undergoing RS were collected in both the CLL and RS phases. A detailed immunophenotypic analysis of formalin-fixed, paraffin-embedded tissue specimens of RS phase was performed, followed by extensive molecular characterisation of CLL and RS samples, including the immunoglobulin heavy chain gene (IGH) rearrangement, TP53 mutations, drug-induced resistance mutations in BTK and BCL2 genes and various copy number changes and point mutations detectable with multiplex ligation-dependent probe amplification (MLPA). Rare, non-diffuse large B-cell lymphoma phenotypes of RS were observed in 3/6 cases, including plasmablastic lymphoma and a transitory entity between diffuse large B-cell lymphoma and classical Hodgkin lymphoma. The majority of cases were clonally related and harboured an unmutated variable region of the immunoglobulin heavy chain gene. Abnormalities affecting the TP53 gene occurred in all patients, and every patient carried at least one genetic abnormality conferring susceptibility to RS. In the background of RS, 2/5 patients treated with ibrutinib showed a BTK C481S resistance mutation. One patient developed a BCL2 G101V mutation leading to venetoclax resistance and RS. In conclusion, our findings contribute to better understanding of RS pathogenesis in the era of targeted oral therapies. Rare phenotypic variants of RS do occur under the treatment of ibrutinib or venetoclax, and genetic factors leading to RS are similar to those identified in patients treated with chemoimmunotherapy. To our best knowledge, we have reported the first BCL2 G101V mutation in an RS patient treated with venetoclax

Investigating the Prognostic Relevance of Tumor Immune Microenvironment and Immune Gene Assembly in Breast Carcinoma Subtypes

We hypothesized that different BC subtypes are characterized by spatially distinct tumor immune microenvironment (TIME) and that immune gene assembly of metastatic (Met) and non-metastatic (Ctrl) BCs vary across subtypes. Peritumoral, stromal and intratumoral TIL was assessed on 309 BC cases. Hot, cold and immune-excluded groups were defined, and the prognostic role of this classification was assessed. CD4+/CD8+ positivity was analyzed in 75 cases in four systematically predefined tumor regions. Immune gene expression of Met and Ctrl HER2-negative BCs was compared by using NanoString nCounter technology. The amount of TIL infiltration varied greatly within all BC subtypes. Two-third of the cases were cold tumors with no significant survival difference compared to hot tumors. A lower CD4+/CD8+ ratio at the stromal internal tumor region was significantly associated with longer distant metastasis-free survival. The differentially expressed immune genes between Met and Ctrl varied across the studied BC subtypes with TNBC showing distinct features from the luminal subtypes. The TIME is characterized by a considerable heterogeneity; however, low level of TILs does not equate to disease progression. The differences in immune gene expression observed between Met and Ctrl breast carcinomas call attention to the important role of altered immune function in BC progression