We studied the clinicopathologic features of 42 cases of nasal-type extranodal natural killer (NK)/T-cell lymphoma in Singapore and compared our findings with other series reported in the Asian and Western populations. A panel of immunohistochemical stains, which included CD2, CD3, CD4, CD8, CD56, T-cell intracellular Antigen-1 and granzyme B, and in situ hybridization for Epstein-Barr virus encoded RNA (EBER) were performed. Polymerase chain reaction for T-cell receptor-gamma gene rearrangement using both gel and capillary electrophoresis were evaluated to determine the proportion of tumors which are of true T-cell lineage. We also studied the functional status of the overexpressed p53 protein in these lymphomas by correlating p53 expression with its downstream target protein, p21. In all, 31 out of 42 cases presented in the upper aerodigestive tract. The other sites of involvement included gastrointestinal tract, skin, soft tissue, testis, liver, spleen, bone marrow and brain. The tumors displayed characteristic morphologic features. In situ hybridization for EBER was detected in 41 out of 42 cases (97.6%). The only significant adverse prognostic factor identified was an International Prognostic Index of two or more. A significantly higher proportion of the tumors (27%), compared to previous studies, demonstrated monoclonal T-cell receptor-gamma gene rearrangement. There was, however, no difference in survival or clinicopathologic features between the true NK-cell tumors and their T-cell counterparts. Overexpression of p53 was present in 40% of the cases, but no significant difference in survival rate was detected in patients with p53 overexpression and there was no association between p53 overexpression with large cell morphology, and advanced stage of disease. These findings suggest that molecular aberrations other than those of the p53 pathway may be operative in the pathogenesis of this malignancy.

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BackgroundIntestinal metaplasia (IM) is an important precursor lesion in the development of gastric cancer (GC). The aim of this study was to investigate genetic factors previously linked to GC risk for their possible association with IM. A total of 18 polymorphisms in 14 candidate genes were evaluated in a Singapore-Chinese population at high risk of developing GC.MethodsGenotype frequencies were compared between individuals presenting with (n = 128) or without (n = 246) IM by both univariate and multivariate analysis.ResultsCarriers of the NQO1 609 T allele showed an association with IM in individuals who were seropositive for Helicobacter pylori (HP+; OR = 2.61, 95%CI: 1.18-5.80, P = .018). The IL-10 819 C allele was also associated with IM in HP+ individuals (OR = 2.32, 95%CI: 1.21-4.43, P = 0.011), while the PTPN11 A allele was associated with IM in HP- individuals (OR = 2.51, 95%CI: 1.16-5.40, P = 0.019), but showed an inverse association in HP+ subjects (OR = 0.46, 95%CI: 0.21-0.99, P = 0.048).ConclusionPolymorphisms in NQO1, IL-10 and PTPN11, in combination with HP status, could be used to identify individuals who are more likely to develop IM and therefore GC.