Combined histology and molecular biology for diagnosis of early stage gastric MALT lymphoma.
OBJECTIVE
To establish a sequential diagnostic procedure of gastric mucosa-associated lymphoid tissue (MALT) lymphoma and provide evidence for selected optimal cases to be treated in the early stage.


METHODS
Thirty-one cases of gastric lymphoid hyperplasia (GLH) were selected and multiple investigations including histology, protein level, DNA and chromosome levels, combined with clinical follow-up were performed. Histological grade was according to Isaacson's criteria of GLH; CD20, UCHL-1 (CD45RO), anti-kappa (kappa), anti-lambda (lambda) and Ki-67 were used for immunohistochemical staining; semi-nested polymerase chain reaction (PCR) was used to detect IgH gene rearrangement and reverse-transcription PCR (RT-PCR) was used to detect API2-MALT1 fusion of the chromosome translocation t(11;18)(q21;q21). Twenty-nine cases underwent eradication therapy for Helicobacter pylori. Changes in histological grade, endoscopic appearance, expression of Ki-67 and IgH gene rearrangement were compared after eradication treatment.


RESULTS
Of the 31 cases of GLH with predominant chronic gastritis and gastric ulcer most were histological grade 2 and 3. Only one case had lambda light chain restriction and 10 cases had monoclonal IgH gene rearrangement. Expression of Ki-67 and monoclonal IgH gene rearrangement were significantly increased with increased lymphoid hyperplasia (P < 0.05). Two cases had API2-MALT1 fusion. Helicobacter pylori was eradicated in 25 cases and another course of treatment had to be given in 4 cases. All cases were followed up for 1.5-37 months. Of the 27 successful eradication cases, 18 showed complete regression both histologically and endoscopically, 4 had partial regression and 7 were unchanged.


CONCLUSIONS
A sequential diagnostic procedure based on histology, expression of Ki-67 combined with clonality of IgH rearrangement and API2-MALT1 fusion helps to diagnosis of early stage gastric MALT lymphoma and choose the best treatment strategy.
Yi
Zhi Hui
ZH
Department of Gastroenterology, West China Hospital, Sichuan Universty, Chengdu, Sichuan Province, China. yizhihui@hotmail.com
Ouyang
Qin
Q
Li
Gan Di
GD
Chen
Dai Yun
DY
D000293:Adolescent; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D004273:DNA, Neoplasm / Q000032:analysis; D005260:Female; D015321:Gene Rearrangement; D016481:Helicobacter Infections / Q000473:pathology; D016480:Helicobacter pylori / Q000235:genetics / Q000302:isolation & purification; D006801:Humans; D018442:Lymphoma, B-Cell, Marginal Zone / Q000235:genetics / Q000473:pathology*; D008297:Male; D008875:Middle Aged; D008967:Molecular Biology; D009367:Neoplasm Staging; D020133:Reverse Transcriptase Polymerase Chain Reaction; D013274:Stomach Neoplasms / Q000235:genetics / Q000473:pathology*
D004273:DNA, Neoplasm