TP53 mutation and BUBR1 overexpression characterize the DNA aneuploidy of gastric cancer.

Abstract

e15039 Background: Gastric cancers show a high frequency of DNA aneuploidy, which is a phenotype of chromosomal instability. Gastric carcinomas with aneuploidy have been shown to have higher proliferative activity and metastatic or invasive potential than diploid tumors, which leads to a poor prognosis. It has been suggested that an abnormal spindle assembly checkpoint is involved in DNA aneuploidy, but the underlying mechanism is still unclear. In this study, we focused on the TP53 gene and BUBR1 protein in gastric cancer to elucidate their relation with the features of DNA aneuploidy. Methods: The study included 178 unselected Japanese patients with primary gastric cancer who underwent gastrectomy between 1994 and 2006 at Kyushu University Hospital, Fukuoka. DNA ploidy status, TP53 gene status, and BUBR1 expression were analyzed. Nuclear DNA content was measured using laser scanning cytometry. The TP53 gene was amplified from exon 5 to exon 9, including exon-intron junctions, by PCR using p53 primers (Nippon Gene, Tokyo, Japan) and Ex Taq DNA polymerase (TaKaRa Bio Inc., Tokyo, Japan). Results: DNA aneuploidy was identified in 108 cases, and TP53 gene mutation was seen in 28 of 143 cases. Both DNA aneuploidy and TP53-mutated tumors correlated with high age and differentiated type tumors. BUBR1 aberrant expression, investigated using immunohistochemistry, was seen in 89 cases, and it correlated with malignant features such as deep invasion, and lymph node and liver metastases. DNA aneuploidy was significantly related to high BUBR1 expression (P = 0.0055), and a more significant relation was found between DNA aneuploidy and TP53mutation (P = 0.0032). Tumors with high BUBR1 expression showed poor prognosis. Conclusions: DNA aneuploidy is associated with the carcinogenesis and prognosis of gastric cancer. Therefore, there has been considerable interest in targeting cell cycle checkpoints, particularly in emerging and alternative anticancer strategies. The development of selection markers to aid in the selection of appropriate therapies for patients will be the primary focus of future research. TP53 mutation and BUBR1 expression may provide clinically useful diagnostic, therapeutic, and prognostic information.