Macroscopic appearance and biological character of gastric cancer invading the muscularis propria

Background/Aims: The natural history of gastric cancer, as to how an early gastric cancer develops into an advanced lesion, is still an open question. In this study, we focused on the gastric cancer invading the muscularis propria, and analyzed the relationship between gross appearance and the biological characteristics of gastric cancer. Materials and Methods: One hundred and forty six patients with gastric cancer invading the muscularis propria (pm) were studied with special reference to the macroscopic appearance of the primary tumor; Borrmann type vs. EGC type (advanced gastric cancer simulating early gastric cancer), and to the biologic characteristics such as p53 expression and mitotic activity. Results: Borrmann type comprised 59.6% (87/146) and EGC type comprised 40.4% (59/146) of the cases. Borrmann type cancer was located more commonly in the antral region (71.3%), tended to grow expansively, and had higher rate of vascular vessel invasion and lymph node metastasis. The type of recurrence varied, and the prognosis was poor in patients with Borrmann type cancer. Incidence of p53 overexpression in Borrmann type cancer was 44.1% (15/34), and significantly higher than 25.8% (8/32) in EGC type cancer. Proliferating activity measured by MIB-1 labeling percentage was also higher in Borrmann type (49.9+/-11.6 vs. 38.9+/-10.9). Conclusions: These results suggest that Borrmann type and EGC type pm gastric cancers are distinct in their inherent biological nature, and possibly represent the advanced form of penetrating growth (Pen) type and superficially-spreading growth (Super) type, respectively, of early gastric cancers.