Extranodal NK/T-cell lymphoma: diagnosis and treatment cues

Frequent STAT3 activation is associated with Mcl-1 expression in nasal NK-cell lymphoma

Nasal natural killer (NK)-cell lymphoma was resistant to various antitumor agents. Although high expression of p-glycoprotein has been reported, other molecular mechanism of the chemo-resistance is largely unknown. Activation of STAT3 and expression of major apoptosis-related proteins Bcl-2, Bcl-x, and Mcl-1 were analyzed by immunohistochemistry. Effects of STAT3 inhibitor AG490 on NK-YS cell line were analyzed by Western blotting and flow cytometric apoptosis assay. STAT3 was activated in six of the nine nasal NK-cell lymphomas (67%). In contrast, STAT3 activation was detected in 35% of diffuse large B-cell lymphoma (DLBCL) and in 10% of follicular lymphoma (FL). Frequent activation of STAT3 was significantly correlated with Mcl-1 expression in nasal NK-cell lymphoma, i.e., Mcl-1 was positive in five of six STAT3-active cases and negative in all three STAT3-inactive ones. In DLBCL, not only six out of seven STAT3-active cases (86%) but also eight out of thirteen STAT3-inactive cases (62%) were positive for Mcl-1 expression. Latent membrane protein-1 was positive in four nasal NK-cell lymphomas, among which three cases showed intermediate STAT3 activation. Inhibition of STAT3 activation by JAK inhibitor AG490 decreased Mcl-1 expression and induced apoptosis in STAT3-active NK-YS cells. Serum starvation rather increased the Mcl-1 level in NK-YS cells, and this effect was also canceled by AG490. These results suggest that activation of STAT3-Mcl-1 axis may play a role in the chemotherapy resistance of nasal NK-cell lymphoma. The pathway may be one of the future therapeutic targets of this intractable disease.

Phase I/II Study of Concurrent Chemoradiotherapy for Localized Nasal Natural Killer/T-Cell Lymphoma: Japan Clinical Oncology Group Study JCOG0211

Purpose

To explore a more effective treatment for localized nasal natural killer (NK)/T-cell lymphoma, we conducted a phase I/II study of concurrent chemoradiotherapy.

Patients and Methods

Treatments comprised concurrent radiotherapy (50 Gy) and 3 courses of dexamethasone, etoposide, ifosfamide, and carboplatin (DeVIC). Patients with a newly diagnosed stage IE or contiguous IIE disease with cervical node involvement and a performance status (PS) of 0 to 2 were eligible for enrollment. The primary end point of the phase II portion was a 2-year overall survival in patients treated with the recommended dose.

Results

Of the 33 patients enrolled, 10 patients were enrolled in the phase I portion and a two thirds dose of DeVIC was established as the recommended dose. Twenty-seven patients (range, 21 to 68; median, 56 years) treated with the recommended dose showed the following clinical features: male:female, 17:10; stage IE, 18; stage IIE, 9; B symptoms present, 10; elevated serum lactate dehydrogenase, 5; and PS 2, 2. With a median follow-up of 32 months, the 2-year overall survival was 78% (95% CI, 57% to 89%). This compared favorably with the historical control of radiotherapy alone (45%). Of the 26 patients assessable for a response, 20 (77%) achieved a complete response, with one partial response. The overall response rate was 81%. The most common grade 3 nonhematologic toxicity was mucositis related to radiation (30%). No treatment-related deaths were observed.

Conclusion

Concurrent chemoradiotherapy using multidrug resistance-nonrelated agents and etoposide is a safe and effective treatment for localized nasal NK/T-cell lymphoma and warrants further investigation.

Extranodal NK/T cell lymphoma, nasal type, of the small intestine diagnosed by double-balloon endoscopy

Extranodal NK/T-cell lymphoma (ENKL), nasal type, is rare and the small intestine is quite extraordinary as a primary lesion site. We report a 47-year-old man with ENKL of the small intestine. He was referred to our hospital because of bloody stool and the diagnosis was made by double-balloon endoscopy (DBE) of the small intestine without surgical procedure. His clinical stage was IVB and he was categorized in group 4 by prognostic index of ENKL. He went into complete remission (CR) after intensive chemotherapy (DeVIC) and subsequently underwent allogeneic bone marrow transplantation (BMT). Although he remained in CR for about 8 months after BMT, he died of disease recurrence 14 months after the diagnosis was made. ENKL of the small intestine follows a highly aggressive course. We describe the usefulness of DBE for diagnosis and management for ENKL of the small intestine. Additional cases, however, should be accumulated to establish optimal treatment strategy.

[A case of CD56+ extranodal NK/T-cell lymphoma, nasal type, presenting as a duodenal ulcer bleeding]

Extranodal NK/T-cell lymphoma is a recently recognized distinct entity within the World Health Organization classification of lymphoid tumors. It is relatively prevalent in Asian and South American populations. It most commonly occurs in the nasal or paranasal areas and less frequently in the skin, the soft tissue, and the gastrointestinal tract. Among these, extranodal NK/T-cell lymphoma of the gastrointestinal tract has shown an aggressive clinical course. We report a case of CD56+ extranodal NK/T-cell lymphoma presenting as a duodenal ulcer bleeding. A 62-year-old male patient presented with melena and abdominal pain. Endoscopic examination of the upper gastrointestinal tract showed the duodenal ulcer covered by blood clot. Pathologic examination revealed the diffuse infiltration of atypical lymphocytes with an angiocentric growth pattern, which was positive for CD3, CD56, and granzyme. The patient showed rapid deteriorating clinical course and died on day 14 after admission. Thus, we report this case with the review of literatures.

Prognostic factors for mature natural killer (NK) cell neoplasms: aggressive NK cell leukemia and extranodal NK cell lymphoma, nasal type

BACKGROUND

Patients with natural killer (NK) cell neoplasms, aggressive NK cell leukemia (ANKL) and extranodal NK cell lymphoma, nasal type (ENKL), have poor outcome. Both diseases show a spectrum and the boundary of them remains unclear. The purpose of this study is to draw a prognostic model of total NK cell neoplasms.

PATIENTS AND METHODS

We retrospectively analyzed 172 patients (22 with ANKL and 150 with ENKL). The ENKLs consisted of 123 nasal and 27 extranasal (16 cutaneous, 9 hepatosplenic, 1 intestinal and 1 nodal) lymphomas.

RESULTS

Complete remission rate for ENKL was 73% in stage I, but 15% in stage IV, which was consistent with that for ANKL (18%). The prognosis of ENKL was better than that of ANKL (median survival 10 versus 1.9 months, P < 0.0001) but was comparable when restricted to stage IV cases (4.0 months, P = 0.16). Multivariate analysis showed that four factors (non-nasal type, stage, performance status and numbers of extranodal involvement) were significant prognostic factors. Using these four variables, an NK prognostic index was successfully constructed. Four-year overall survival of patients with zero, one, two and three or four adverse factors were 55%, 33%, 15% and 6%, respectively.

CONCLUSION

The current prognostic model successfully stratified patients with NK cell neoplasms with different outcomes.

Advances in the management and monitoring of extranodal NK/T-cell lymphoma, nasal type

Extranodal natural killer (NK)/T-cell lymphoma, nasal type, has a unique geographic distribution. Its pathology is characterized by marked angio-invasion and tissue necrosis. A typical NK-cell phenotype is usually present: CD2(+), CD3 epsilon+, CD56(+), cytotoxic molecules+ and Epstein-Barr virus (EBV)+. Magnetic Resonance Imaging helps to clearly define the local involvement. Positron Emission Tomography helps to demonstrate system spread. Various prognostic variables (International Prognostic Index or the Korean Prognostic Index) should be documented. This may include quantification of plasma EBV DNA. For localized nasal disease, radiotherapy is important, although chemotherapy is often added. Sustainable remission is observed in over half of these patients. For extra-nasal or disseminated disease, systemic chemotherapy becomes the mainstay and the prognosis is usually poor. Doxorubicin-containing regimens are not entirely satisfactory and L-asparaginase containing regimens are being investigated. Patients with poor prognostic features may be considered for an early autologous haematopoietic stem cell transplant. Allogeneic transplantation is efficacious but is associated with high transplant-related mortality.