NK/T-cell lymphomas ‘nasal type’: an Italian multicentric retrospective survey

The enhanced expression of the matrix metalloproteinase 9 in nasal NK/T-cell lymphoma

Background

Nasal NK/T cell lymphoma is an aggressive disease and has a poor prognosis. Nasal NK/T cell lymphoma is refractory to conventional chemotherapy and has strong tendency of widespread relapse or dissemination into distant sites.

Methods

We immunohistochemically studied nasal NK/T-cell lymphoma to elucidate the unique characteristics of nasal NK/T-cell lymphoma, such as its higher metastatic tendency and its vast necrosis which leads to destruction of the involved tissues. The expression of P-glycoprotein and MMP-9 was evaluated in the 20 patients with nasal NK/T-cell lymphoma and 25 with nasal non-NK/T-cell lymphoma and the relationship between expression of these proteins and clinical results were analyzed in this report.

Results

Overall 5-year survival rates for patients with nasal NK/T cell lymphoma, and nasal non-NK/T cell lymphoma were 51%, and 84%. Distant involvement free 5-year survival rates for patients with nasal NK/T cell lymphoma, and nasal non-NK/T cell lymphoma were 53%, and 79%.

Overall positivity for P-glycoprotein was observed in 10 of 19 patients with NTL and in 13 of 23 patients with non-NTL. When the overall survival rate was compared between patients with P-glycoprotein positive and negative, there was no difference between them.

Sixteen of the 19 patients with nasal NK/T cell lymphoma expressed MMP-9. In contrast, only 8 of the 22 patients with nasal non-NK/T cell lymphoma expressed MMP-9. Distant involvement free 5-year survival rates for patients with MMP-9 negative, and MMP-9 positive were 92%, and 61%, respectively. The difference was statistically significant (p = 0.027).

Conclusion

Positive immunoreactivity for P-glycoprotein was not an independent prognostic factor in nasal NK/T-cell lymphomas, which stresses the importance of exploring other mechanisms of drug resistance. The strong expression of MMP-9 is uniquely characteristic of nasal NK/T cell lymphoma and may contribute to its strong tendency to disseminatate and the extensive necrosis which is always seen. However, our results are based on univariate comparisons, and as such, should be viewed with some caution.

Prognostic factors for classifying extranodal NK/T cell lymphoma, nasal type, as lymphoid neoplasia

This study evaluated the applicability of prognostic factors commonly used for diagnosis of classical lymphoma outcomes to extranodal NK/T cell lymphoma, nasal type (NTCL). Clinical features and their associations with lactate dehydrogenase (LDH) were evaluated in 70 patients. RLDH was defined as the ratio of LDH to the upper normal limit. RLDH was associated with stage (I-II vs. III-IV), lymph node involvement (LNI), and International Prognostic Index score (<2 vs. > or =2). Poor performance status and advanced stage were common in patients with local tumor invasiveness (LTI). LDH level, classified into three levels (low, high, and very high) was associated with survival (P < 0.001). In multivariate analysis, the predictive values of LDH level, B symptom, performance status, and stage remained significant whereas those of LTI and LNI did not. Scoring was performed by weighting each factor with 0.5 or 1.0 according to its hazard ratio. Scores were classified into four groups. Groups with high scores were associated with unfavorable outcomes (P < 0.001). Current study suggests that prognostic factors for NHL may be useful to predict the outcome of NTCL but the model should take LDH level and the prognostic weight of each factor into account.

Expression of the granzyme B inhibitor PI9 predicts outcome in nasal NK/T-cell lymphoma: results of a Western series of 48 patients treated with first-line polychemotherapy within the Groupe d'Etude des Lymphomes de l'Adulte (GELA) trials

Nasal NK/T-cell lymphoma is a rare disease entity with a poor outcome. Expression of antiapoptotic proteins has not been extensively investigated in this entity. Forty-eight patients with nasal T/NK-cell lymphoma who received first-line polychemotherapy (n = 44) or chemoradiotherapy (n = 4) were analyzed for expression of active caspase-3 (aC3), granzyme B protease inhibitor 9 (PI9), and Bcl-2 proteins. Lymphomas were CD3+/CD5−/granzyme B+ and EBV-associated. Median age was 46 years. Stage I/II disease was present in 75% of the cases and an International Prognostic Index (IPI) score less than 1 in 65%. With a median follow-up of 6.3 years, 5-year event-free survival (EFS) and overall survival (OS) rates were 39% and 49%, respectively. Apoptotic index was scored as high in 32% of cases and PI9 expression as positive in 68%, whereas 35% disclosed a high number of aC3+ tumor cells. Univariate analysis showed that absence of PI9 and low apoptotic index were associated with poor outcome, but not aC3 expression nor IPI score. By multivariate analysis, both parameters affected independently EFS (P = .02 and .08, respectively) and OS (P = .009 and .04). In view of its constitutive expression by normal NK cells, it is suggested that loss of PI9 expression in tumor cells may reflect some mechanism associated with progression.