p53 evaluation in gastric mucosa of patients with chronic Helicobacter pylori infection.

Gastric cancer is often associated with p53 over-expression and Helicobacter pylori (HP) infection. In this study we have investigated the production of the p53 protein and mutation of its gene in precancerous gastric lesions with HP infection. For this purpose 130 patients who underwent endoscopy for dyspepsia were enrolled in the study. To assess p53 production and mutation of the p53 gene we employed an immunoluminometric assay and polymerase chain reaction single strand conformation polymorphism (PCR-SSCP) analysis, respectively. Histologically, 52 of the 130 enrolled patients showed intestinal metaplasia type I (IM) (90.4% of these were also HP positive), 47 had HP-related gastritis and 31 were normal. p53 cytosol levels were significantly higher in patients with IM or HP-related gastritis than in normal patients (p = 0.0137 and p = 0.0411, respectively). All DNAs extracted from gastric mucosa samples with higher p53 values and examined for p53 mutations by PCR-SSCP analysis were characterized by a normal run. Our data indicate, that irreversible genetic changes in the p53 protein has not yet occurred in morphologically non-neoplastic gastric mucosa with IM and HP-related chronic gastritis. In conclusion, the increase in p53 cytosolic levels found in our study is due to an increased production of the wild-type protein probably related to an inflammatory response induced by HP infection.

Survivin is expressed on CD40 stimulation and interfaces proliferation and apoptosis in B-cell chronic lymphocytic leukemia.

In B-cell chronic lymphocytic leukemia (B-CLL), defective apoptosis causes the accumulation of mature CD5(+) B cells in lymphoid organs, bone marrow (BM), and peripheral blood (PB). These cells are the progeny of a proliferating pool that feeds the accumulating compartment. The authors sought to determine which molecular mechanisms govern the proliferating pool, how they relate to apoptosis, and what the role is of the microenvironment. To begin to resolve these problems, the expression and modulation of the family of inhibitor of apoptosis proteins (IAPs) were investigated, with consideration given to the possibility that physiological stimuli, such as CD40 ligand (CD40L), available to B cells in the microenvironment, might modulate IAP expression. The in vitro data on mononuclear cells from PB or BM of 30 patients demonstrate that B-CLL cells on CD40 stimulation express Survivin and that Survivin is the only IAP whose expression is induced by CD40L. Through immunohistochemistry, in vivo Survivin expression in lymph node (LN) and BM biopsies was evaluated. In reactive LN, Survivin was detected only in highly proliferating germinal center cells. In LN from patients with B-CLL, Survivin was detected only in pseudofollicles. Pseudofollicle Survivin(+) cells were actively proliferating and, in contrast to Survivin(+) B cells found in normal GC, were Bcl-2(+). In B-CLL BM biopsies, CD5(+), Survivin(+) cells were observed in clusters interspersed with T cells. These findings establish that Survivin controls the B-CLL proliferative pool interfacing apoptosis and that its expression may be modulated by microenvironmental stimuli.