Immunohistochemical Expression of p53 Protein and CREB-binding Protein in Gastric Adenocarcinomas

Noh, Tae Ho; Chi, Kyung Choun; Lim, Hyun Muk; Lee, Jung Hyo; Park, Yong Gum; Kim, Beom Gyu; Kim, Mi Kyung; Kim, Jin Soo

Abstract

PURPOSE: The wild-type p53 protein participates in suppressing cell transformations while its mutant forms has tumorigenic potential. Alterations in the structure of the p53 protein are one of the most common changes associated with human cancers. CREB-binding protein (CBP) and its homologue, p300, are transcriptional co-activators of various sequence-specific DNA-binding transcription factors and are involved in a wide range of cellular activities, such as DNA repair, cell growth, differentiation, and apoptosis. Several studies suggested that an association between p53 and p300 might account for the p53-responsible negative regulation. This study examined the relationship between p53 and CBP expression in terms of the clinicopathological factors and significance.
METHODS
The level of p53 protein and CBP expression was measured in 150 gastric adenocarcinoma patients, who had undergone a gastrectomy, and the relationship between p53 and CBP was examined. Immunohistochemical stain was performed on formalin-fixed paraffin-embedded sections using monoclonal anti-p53 and anti-CBP antibody.
RESULTS
1. p53 protein was expressed in 46.3% (31/67) of early gastric cancers (EGC), 69.9% (58/83) of advanced gastric cancers (AGC)(P<0.05), 69.1% (65/94) of the intestinal type, 42.9% (24/56) of the diffuse type (P<0.05), 78.5% (55/70) of patients with a lymph node metastasis and 42.5% (34/80) of patients without a lymph node metastasis (P<0.01). 2. CBP expression was observed in 65% (61/94) of intestinal type, 51% (29/56) of the diffuse type (P>0.05), 47.8% (32/67) of EGC, 69.8% (58/83) of AGC (P<0.05), 68.6% (48/70) of patients with a lymph node metastasis and 52.5% (42/80) of patients without a lymph node metastasis (P>0.05). 3. p53 protein and CBP expression was coincidentally observed in 66.7% of gastric adenocarcinomas, and there was a significant correlation between the expression of both (P<0.05).
CONCLUSION
That the expression of the p53 protein and CBP indirectly indicate the malignant potential of a cell, and may play an indirect role in the CBP and p53-mediated tumorigenic potential.