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Apoptosis, inflammatory bowel disease and carcinogenesis: Overview of international and Greek experience
J Kountouras | G Kouklakis | C Zavos | D Chatzopoulos | et al
Apoptosis
is critical for organ development, tissue homeostasis,
the elimination of abnormal cells and the maintenance
of immune homeostasis by variable regulatory mechanisms.
The death of T lymphocytes following their activation
involves a series of proteases (caspases), which comprise
the central executioners of apoptosis. Abnormal regulation
of apoptosis results in disease. T-cell resistance against
apoptosis contributes to inappropriate T-cell accumulation
and the perpetuation of the chronic inflammatory process
in inflammatory bowel disease with potential tumourigenic
effect. The use of antitumour necrosis factor-alpha,
anti-interleukin-6R and anti-interleukin-12 antibodies
suppresses colitis activity by induction of
T-cell apoptosis, thereby having important implications
for the design of effective therapeutic strategies in
inflammatory bowel diseases. Contrary to international
data, the incidence of cancer in Greek patients with
inflammatory bowel disease appears to be low. A balance
between cell proliferation (Ki-67 overexpression) and
apoptosis (Bax protein overexpression) may partly explain
the low incidence of cancer development in Greek inflammatory
bowel disease patients.
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