MATERIALS & METHODS: In total 141 local series of DLBCL cases from UKM Medical Centre were retrospectively studied.
RESULTS: Of these cases, we classified our patients into two subtypes: 32.7% (37/113) GCB and non-GCB 67.3% (76/113) by Hans algorithm and the results showed strong agreement with the results by Choi algorithm (κ = 0.828, P<0.001). Survival analysis indicated significant difference in between GCB and non-GCB subtypes (P=0.01), elevated serum LDH (P=0.016), age more than 60-year-old (P=0.021) and the presence of B symptoms (P=0.04). We observed 12% DLBCL cases were CD5 positive and 81.8% of them died of the disease (P=0.076). Analysis on the dual expression of MYC/BCL2 revealed that there is no significant difference in DE and non-DE groups (P=0.916). FISH study reported there were 9.22% (13/141) rearranged cases observed in our population at which highest frequency of BCL6 gene rearrangement (76.9%), followed by MYC (15.4%) and BCL2 (7.7%); no BCL10 and MALT-1 gene rearrangement found regardless of using TMAs or whole tissue samples. More cases of MYC protein overexpression observed compared to MYC translocation.
CONCLUSION: Relatively lower frequency of GCB tumours and low gene rearrangement rates were observed in Malaysian population. A national study is therefore warranted to know better the immunogenotypic characteristics of DLBCL in Malaysia and their implications on the survival.
METHODS AND RESULTS: A total of 232 reconfirmed lymphoma cases in Malaysian patients were retrieved from the archives in the Department of Pathology, University Hospital, Kuala Lumpur. There were 24 (10%) Hodgkin's and 208 (90%) non-Hodgkin's lymphomas, 173 of the latter were in adult group (aged > or = 15 years). The ethnic composition were 41 Malays, 107 Chinese, 21 Indians and four none of the above. A male : female ratio of 2.4 : 1 was observed. Complete immunohistochemical studies in 158 cases revealed 36 (23%) T-cell, 121 (76%) B-cell and one (1%) null-cell phenotype. Seventy-five percent of the T-cell lymphomas were peripheral T/NK-cell types. Among the classifiable lesions, low-grade/indolent lymphomas constituted 17%: 2% were the lymphocytic subtype and 10% were follicular lymphomas. Approximately one-third of the follicular lymphomas occurred in Indian patients. The largest group of high-grade lymphoma was diffuse large B-cell type (46%), followed by peripheral T/NK-cell (18%). A predominance of NK/T-cell lymphomas occurred in Chinese (5/7), and all were EBV associated. Burkitt's lymphoma accounted for 5% (eight cases), all were Chinese males, with a 38% EBV-association rate. The frequency of EBV-associated B-cell lymphoma is three times more common in Chinese than Malays. The EBV positivity rate among lymphomas in ethnic Malay, Chinese and Indian patients was 5%, 15% and 22%, respectively, and in T- and B-cell lymphomas was 36% and 7%, respectively.
CONCLUSIONS: This Malaysian series reveals differences in the subtype frequencies of non-Hodgkin's lymphomas and EBV association rate amongst patients of various ethnic groups residing in the same environment.