Purpose To elucidate the management and outcomes of patients with extranodal natural killer/T-cell lymphoma, nasal type (ENKL), who were diagnosed between 2000 and 2013 in Japan. Patients and Methods Data from 358 patients with ENKL diagnosed between 2000 and 2013 from 31 institutes were retrospectively analyzed. Results Patients' median age was 58 years, and 257 (72%) had localized disease. The most common first-line treatment was radiotherapy with dexamethasone, etoposide, ifosfamide, and carboplatin (RT-DeVIC) (66%) for localized ENKL and L-asparaginase-containing chemotherapy (30%) for advanced ENKL. With a median follow-up of 5.8 years, overall survival (OS) rates at 5 years for localized and advanced ENKL were 68% and 24%, respectively. The prognostic index of natural killer lymphoma was validated in our study, although only 4% of patients with localized ENKL were classified as high risk. With a median follow-up of 5.6 years, OS and progression-free survival at 5 years in the 150 patients who received RT-DeVIC in clinical practice were 72% (95% CI, 63% to 78%) and 61% (95% CI, 52% to 69%), respectively. Toxicities of RT-DeVIC were comparable to those in a previous trial. Multivariate analysis in patients with localized ENKL who received RT-DeVIC identified elevated soluble interleukin-2 receptor as an independent predictive factor for worse OS and progression-free survival (adjusted hazard ratios, 2.28 and 2.46; 95% CI, 1.24 to 4.23 and 1.42 to 4.28; P = .008 and .0014, respectively). Conclusion Favorable OS in response to new treatments was demonstrated in a large number of patients. Improved treatment approaches are needed for localized ENKL exhibiting elevated pretreatment soluble interleukin-2 receptor.

Aggressive natural killer-cell (NK-cell) leukemia (ANKL) is an extremely aggressive malignancy with dismal prognosis and lack of targeted therapies. Here, we elucidate the molecular pathogenesis of ANKL using a combination of genomic and drug sensitivity profiling. We study 14 ANKL patients using whole-exome sequencing (WES) and identify mutations in STAT3 (21%) and RAS-MAPK pathway genes (21%) as well as in DDX3X (29%) and epigenetic modifiers (50%). Additional alterations include JAK-STAT copy gains and tyrosine phosphatase mutations, which we show recurrent also in extranodal NK/T-cell lymphoma, nasal type (NKTCL) through integration of public genomic data. Drug sensitivity profiling further demonstrates the role of the JAK-STAT pathway in the pathogenesis of NK-cell malignancies, identifying NK cells to be highly sensitive to JAK and BCL2 inhibition compared to other hematopoietic cell lineages. Our results provide insight into ANKL genetics and a framework for application of targeted therapies in NK-cell malignancies.

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Large granular lymphocyte leukemia (LGL L) has been morphologically characterized as a group of lymphoproliferative diseases that include T-cell large granular lymphocytic leukemia (T-LGL L) and chronic lymphoproliferative disorders of natural killer cells (CLPD-NK). We investigated mutations in the Src homology 2 (SH2) domain of the signal transducer and activator of transcription 3 (STAT3) gene in Asian cohorts of T-LGL L and CLPD-NK (n = 42 and 11, respectively). Two mutations, Y640F and D661Y, were identified using direct sequencing or allele-specific (AS) PCR. Y640F and D661Y mutations were found in seven and 18 patients, respectively. Two patients were positive for both mutations. Frequencies of STAT3 mutations in T-LGL L and CLPD-NK were 47.6% and 27.2%, respectively. Pure red cell aplasia (PRCA) was associated with the mutations (P = 0.005). The mutations were persistently found at stable levels in some patients after more than 5 years using AS-quantitative PCR. The results of the present study indicate that the SH2 domain of the STAT3 gene is frequently mutated in Asian T-LGL L and CLPD-NK, and that PRCA is closely correlated with the mutations.

A 58-year-old woman with a histologically confirmed diagnosis of vulvar extramammary Paget's disease (EMPD) was referred to our hospital due to locally advanced and relapsed EMPD. The patient had undergone surgical resection three times for relapsed vulvar EMPD over a period of 12 years, but developed locally advanced and unresectable EMPD. As pathological examination indicated that the lesion was positive for human epidermal growth factor receptor 2 (HER2) on immunohistochemical staining, the patient was treated with trastuzumab plus paclitaxel. The primary tumor mass and lymph node metastasis regressed successfully with combined trastuzumab and paclitaxel therapy, and the disease has been stable for >2 years after the initiation of treatment. These observations suggest that HER2 status must be determined in patients with advanced and/or metastatic extramammary Paget's disease and therapy with HER2 inhibitors should be considered as an option for the treatment of HER2-positive EMPD.