Bcl-6 expression and lactate dehydrogenase level predict prognosis of primary gastric diffuse large B-cell lymphoma.
OBJECTIVE
The gastrointestinal tract is the most common site of primary extranodal non-Hodgkin lymphoma, and the prognostic factors of primary gastric diffuse large B-cell lymphoma (PG-DLBCL) differ in various studies.


METHODS
We retrospectively searched for PG-DLBCL in a single institution, performed immunohistochemical analysis, classified tumor phenotype (Hans and Muris algorithms), reviewed medical records, and analyzed the clinical and immunophenotypic variables using Cox proportional hazard regression model.


RESULTS
A total of 46 cases were identified including 25 males and 21 females with a median age of 63.5; 18 (39%) were at stage I and 28 (61%) at stage II. Seven (15%) patients underwent surgery as initial treatment including total (n = 3, 7%) and subtotal (n = 4, 9%) gastrectomy. Thirty-three patients (72%) received frontline chemotherapy treatment including ten with additional rituximab (MabThera) injection, and two (6%) of these patients developed perforation after chemotherapy. Four patients passed away shortly after diagnosis and the remaining three were lost to follow-up. The overall 2- and 5- year survival rates were 55% and 50%, respectively. The expression of various differentiation markers was CD10 (25%), bcl-2 (50%), bcl-6 (84%), and MUM1 (64%). Half of the cases studied (22/44) were classified as germinal center B-cell (GCB) phenotype and the remaining half as non-GCB according to Hans algorithm; 66% and 34% cases belonged to groups 1 and 2, respectively, according to Muris algorithm. Univariate analysis showed the expression of bcl-6 by the tumor cells as a favorable factor, while elevated serum lactate dehydrogenase (LDH) level, bcl-2 expression, and Muris group 2 were associated with poorer outcome. Multivariate analysis revealed that the two prognostic factors were bcl-6 expression and elevated LDH level, with hazard ratios of 0.09 (p = 0.002) and 3.72 (p = 0.024), respectively.


CONCLUSIONS
In this retrospective study with heterogeneous treatment modality, we identified bcl-6 expression and elevated LDH level as two prognostic factors for PG-DLBCL.
Department of Internal Medicine, Chi-Mei Medical Center, Tainan, Taiwan.
Kun-Ming
KM
Chung
Sheng-Tsung
ST
Chang
Wen-Tsung
WT
Huang
Chin-Li
CL
Lu
Hung-Chang
HC
Wu
Wei-Shou
WS
Hwang
Kwang-Yu
KY
Chang
Shih-Sung
SS
Chuang
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004268:DNA-Binding Proteins / Q000032:analysis*; D005260:Female; D006801:Humans; D006836:Hydro-Lyases / Q000097:blood*; D016403:Lymphoma, Large B-Cell, Diffuse / Q000737:chemistry* / Q000201:enzymology / Q000628:therapy; D008297:Male; D008875:Middle Aged; D010641:Phenotype; D011379:Prognosis; D051560:Proto-Oncogene Proteins c-bcl-6; D012189:Retrospective Studies; D013274:Stomach Neoplasms / Q000737:chemistry* / Q000201:enzymology / Q000628:therapy; D015996:Survival Rate; D055815:Young Adult
C084103:BCL6 protein, human; D004268:DNA-Binding Proteins; D051560:Proto-Oncogene Proteins c-bcl-6; D006836:Hydro-Lyases; C045581:lactate dehydratase
Taiwan; bcl-6; diffuse large B-cell lymphoma; germinal center B-cell phenotype; primary gastric lymphoma; stomach