Histiocytic and dendritic cell neoplasms: Reappraisal of a Japanese series based on t(14;18) and neoplastic PD-L1 expression.

Histiocytic and dendritic cell (H/DC) neoplasms are heterogeneous, originating from myeloid- or stromal-derived cells. Multiple reports describe the cross-lineage transdifferentiation of neoplastic B cells into H/DC neoplasms. Most such cases are from Western countries, and rarely from Japan or East Asia. Here we report 17 cases of H/DC neoplasms in Japanese patients, with analysis of t(14;18) by fluorescence in situ hybridization, and of neoplastic programmed death-ligand 1 (PD-L1) expression by immunostaining (clones SP142, E1J2J, and 28-8). These 17 cases were diagnosed according to the 2017 World Health Organization (WHO) classification, and included two histiocytic sarcomas (HS), two interdigitating cell (IDC) sarcomas, one Langerhans cell sarcoma, two dendritic cell sarcomas, and 10 follicular dendritic cell (FDC) sarcomas. No case had any past history of follicular lymphoma (FL). Two cases of HS and one IDC sarcoma, all of which were myeloid-driven, were found to exhibit t(14;18). In the latter case, at 30 months after IDC sarcoma diagnosis, FL development was detected. Three (30%) FDC sarcoma cases exhibited neoplastic PD-L1 expression with all the three PD-L1 antibody clones. This is the first report of t(14;18) and neoplastic PD-L1 expression on H/DC neoplasms among Japanese patients, each of which appeared to be associated with HS and FDC sarcoma, respectively.

[Biomarkers of Leukemia ~Description of the Practical Use and Operation in the Clinical Laboratory~]-.

Genetic testing of hematological malignancy is-.indispensable to categorize and diagnose leukemia. The quantitation of fusion gene mRNA built up by chromosomal translocation including BCR-ABL1 (major, minor), RUNX1-RUNX1T1, and PML-RARA and detection of the JAK2 (V617F) mutant gene are performed by our- selves in our hospital. Efficient, practical use is necessary because the number of medical technologists is limited and numbers of tests are increasing annually. The detection of leukemic cells is important in hematological tests. In addition, experienced medical technologists can predict the existence of fusion mutant genes. In this report, we introduce our experience regarding the practical use and operation of biomarkers for leukemia. Medical technologists take advantage of peripheral blood tests for screening, such as the complete blood count (CBC), hemogram, fibrin and fibrinogen degradation products (FDP), and the quantitation of fusion gene mRNA, which offers a definitive diagnosis including BCR-ABL1, RUNX1-RUNX1T1, and PML-RARA, and genetic tests are performed efficiently. [Review].

[KRAS Genetic Mutation Analysis Using the Clinical FFPE Samples of Colorectal Carcinomas: Comparative Study among 5 Methods].

Targeting of epidermal growth factor receptor (EGFR) with monoclonal antibodies such as cetuximab or panitumumab inhibits the activation of downstream signaling molecules of EGFR. Since EGFR inhibitor therapy has been approved for the treatment of colorectal carcinomas in patients with tumors lacking KRAS mutations, the detection of KRAS mutation is indispensable before starting therapy. Although several laboratory procedures have been developed to detect KRAS mutations, few comparative studies of the sensitivity of mutation detection have been performed for such procedures. Here, we compared the levels of detection in 5 commercial KRAS mutation detection methods using both standard DNA samples and formalin-fixed clinical samples obtained during surgery. Scorpion-ARMS assay has been reported as the most sensitive and we compared 4 other methods with Scorpion. Both PCR-rSSO assay and F-PHFA assay showed the highest concordance. As for the detection sensitivity, there were variations between clinical samples apparently due to sample quality or assay principles and methods. It is thus suggested that routine validation is required using samples prepared in each lab and the choice of assay may depend on various factors, such as lab environment, actual needs of physicians and patients, and the quality of the formalin-fixed specimens.