Journal Article Identification of cell-type-specific mutations in nodal T-cell lymphomas

Nguyen, T B  ,  Sakata-Yanagimoto, M  ,  Asabe, Y  ,  Matsubara, D  ,  Kano, J  ,  Yoshida, K  ,  Shiraishi, Y  ,  Chiba, K  ,  Tanaka, H  ,  Miyano, S  ,  Izutsu, K  ,  Nakamura, N  ,  Takeuchi, K  ,  Miyoshi, H  ,  Ohshima, K  ,  Minowa, T  ,  Ogawa, S  ,  Noguchi, M  ,  Chiba, S

7p.e516 , 2017-01 , Nature Publishing Group
Recent genetic analysis has identified frequent mutations in ten-eleven translocation 2 (TET2), DNA methyltransferase 3A (DNMT3A), isocitrate dehydrogenase 2 (IDH2) and ras homolog family member A (RHOA) in nodal T-cell lymphomas, including angioimmunoblastic T-cell lymphoma and peripheral T-cell lymphoma, not otherwise specified. We examined the distribution of mutations in these subtypes of mature T-/natural killer cell neoplasms to determine their clonal architecture. Targeted sequencing was performed for 71 genes in tumor-derived DNA of 87 cases. The mutations were then analyzed in a programmed death-1 (PD1)-positive population enriched with tumor cells and CD20-positive B cells purified by laser microdissection from 19 cases. TET2 and DNMT3A mutations were identified in both the PD1+ cells and the CD20+ cells in 15/16 and 4/7 cases, respectively. All the RHOA and IDH2 mutations were confined to the PD1+ cells, indicating that some, including RHOA and IDH2 mutations, being specific events in tumor cells. Notably, we found that all NOTCH1 mutations were detected only in the CD20+ cells. In conclusion, we identified both B- as well as T-cell-specific mutations, and mutations common to both T and B cells. These findings indicate the expansion of a clone after multistep and multilineal acquisition of gene mutations.

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