Background: A high percentage of early-stage, high-grade
gastric mucosa associated lymphoid tissue (MALT) lymphomas
remain Helicobacter pylori dependent.
Aim: This study aims to determine the possible role of
B-cell clonality in distinguishing reactive from malignant
infiltrate in H. Pylori associated gastritis and MALT lymphoma,
the association between cell cycle regulatory protein, cyclin
Bl. and apoptotic cell death during the progression of MALT
lymphoma and to identify protein marker that may help in
recognition of the population that at increased risk of developing
MALT lymphoma.
Materials and Methods: This study carried out on 80
cases of gastric specimens (47 cases were dignosed as chronic
gastritis (35 score 1&2, 12 cases were score 3&4), and 33
cases are of gastric MALT lymphoma and normal control
endoscopic biopsies of stomach were included (N:5), Sections
were prepared from formalin fixed paraffin embedded blocks
for (1) Haematoxylin and eosin (H&E) stain, (2) Geimsa stain
for detection of H. Pylori infection, (3) immunohistochemical
staining for detection of cyclin BI overexpression, (4) quantification
of apoptic cells using TUNEL, and (5) PCR studies
of B cell clonality.
Results: In this study the, H. Pylori was detected in chronic
gastritis, and in low grade rather than high grade MALT
lymphoma. It is also detected in cases localized to submucosa
and cases lacking LN metastasis. Cyclin B1 labeling index
was higher in MALT lymphoma cases when compared to
chronic gastritis cases where cyclin B I LI was 2.3 and 3.4
folds respectively (significant correlation, p<0.01). The mean
cyclin B1 LI was higher in cases with LN metastasis. There
is significant correlation between H. Pylori and cycling B1
LI in MALT cell lymphoma cases with deep layers invasion
only, on the other hand, the mean apoptotic index (Al) of
chronic gastritis score 3&4 was higher than that of gastritis
score l&2 and MALT lymphoma (1.26%, 0.37%, and 0.9%
respectively), at the same time it increased in cases with high
grade than low grade cases (1.84% and 0.61%) with high
significant p value (0.003). No significant correlation was
found between Al to H pylori, LN metastasis, or staging of
lymphoma cases. There is significant inverse correlation
between cyclin BI LI, and Al in H. Pylori associated cases.
As regard to PCR results: Oligoclonal bands were detected
in 14.3% of MALT lymphoma, and monoclonal bands with
or without background smear in 71.4%, the polyclonal pattern
were detected in 14.3% of MALT lymphoma cases.
Conclusion: These results suggest that cyclin B1 expression
may be actively associated in the modulation of cellular
death by apoptosis, as well as cellular proliferation and
transformation during the evolution of H.pylori-associated
gastritis to MALT lymphoma. Also the detection of a single
clear and reproducible band by PCR strongly support the
presence of a malignant clone in gastric biopsies. Collectively
these results may help in recognition of the population that
at increased risk of developing MALT lymphoma.
Key Words: Gastric mucosa associated lymphoid tissue
(MALT) — Helicobacter pylori — Immunohistochemical
— PCR Study.
Introduction |
