Predictive value of Ki-67, p53 protein, and DNA content in the diagnosis of gastric carcinoma

Background: The ability to make a precise preoperative diagnosis is a valuable and effective method in improving the prognosis of patients with gastric carcinoma. The authors examined retrospectively whether preoperative histopathologic analysis with p53 protein, Ki-67 labeling index, and DNA ploidy along with preoperative radiographic and endoscopic findings led to a precise preoperative diagnosis of patients with gastric carcinoma.

Methods: Histopathologic analysis of p53 protein, Ki-67 labeling index, and DNA content was performed on formalin fixed, paraffin embedded tissue. Tissue sections from endoscopic and surgically resected specimens were stained immunohistochemically for p53 protein and Ki-67 labeling index, and the cell nuclear DNA content of the surgically resected primary lesion was measured using a microspectrophotometer. These analyses were performed on 16 patients with early gastric carcinoma (EGC) who were diagnosed with advanced gastric carcinoma (AGC) based on the preoperative imaging findings and on 15 patients with AGC who were diagnosed preoperatively with EGC.

Results: Overexpression of p53 in the AGC group was significantly more frequent compared with that in the EGC group (P = 0.0386). With regard to the correlation between lymph node metastases and p53 overexpression, there was no apparent relation in either the AGC group (P = 0.648) or the EGC group (P = 0.726). The AGC group had significantly higher Ki-67 labeling indices compared with the EGC group (P = 0.0195). There was complete concordance between endoscopic and surgically resected specimens with regard to the p53 and Ki-67 labeling index findings. DNA ploidy in the primary tumor did not differ between the AGC and EGC groups. The survival rates for the EGC group were significantly superior to those for the AGC group (P = 0.0312).

Conclusions: The findings of the current study suggest that in routine clinical practice, the combination of preoperative imaging findings in addition to Ki-67 labeling indexes, and p53 protein analyses may be useful for the accurate diagnosis of EGC; however, DNA ploidy did not appear to reflect the growth potential of gastric carcinoma.