Protein expression of bax, bcl-2, and p53 in patients with non-Hodgkin's gastric lymphoma: Prognostic significance

The biologic significance of bcl-2, bax, and p53 gene expression in patient s with non-Hodgkin's gastric lymphoma is unknown. We examined the prognosti c value of these genes in 36 patients with gastric lymphoma treated in our clinic between 1990 and 1995. Paraffin-embedded specimens from 36 patients who underwent primary resection of the stomach for gastric lymphoma were an alyzed immunohistochemically for p53, bax, and bcl-2 gene expression. Expre ssion of bax was seen in 24 of 36 patients (66.7%), p53 expression was foun d in 8 of 36 tumors (22.2%), and bcl-2 cytoplasmic staining was detected in 6 of 36 patients (16.7%). We performed a univariate analysis to examine th e possible correlation between the expression of these genes and the surviv al of our patients. Expression of bax protein proved to be a statistically significant prognostic factor (p = 0.049). Protein expression of p53 and bc l-2 did not statistically correlate with survival. In the bcl-2-negative (- ) patient group (30 patients). those who were bax-positive had a statistica lly significant better survival than those who were bax-negative (63.3% vs. 36.7%, p = 0.03). There was also a statistically significant correlation b etween p53 expression and the grade of the tumor (p = 0.0014). P53 protein expression increased along with the grade. Expression of bax is a significa nt prognostic factor in patients with gastric lymphoma. Its prognostic valu e increases significantly when studied in bcl-2-negative patients: hut expr ession of bax failed to be an independent prognostic factor. Expression of bcl-2 and p53 has no prognostic significance. Expression of p53 seems to re present a marker for loss of differentiation.