The function of omental milky spot in gastric cancer peritoneal mestastasis

Abstract

Objective To study the function of omental milky spot in gastric cancer peritoneal mestastasis. Methods 1 × 10~4 Dil labeled MFC cells were injected intrapentoneally (72 mice) , and the animals were killed at different time points after intraperitoneal injection. The omenta was excised for im-munohistochenustry. Results At the 12th h post injection, gastric cancer cells were particularly concen-trated in milky spots. After 48 h, number of gastric cancer cells was declined in milky spot areas for the reason of the killing function of macrophages. After 72 h, number of Dil-MFCs was further decreased in milky spot areas, and proliferating tumor cells were observed in milky spots and formed nucrometastasis. In contrast, sporadic gastric cancer cells in non-milky spot areas were found at the 48th h after intraperitoneal injection. After 72 h, number of Dil-MFCs in milky spots was increased. Two weeks after intraperitoneal injection, milky spot area was occupied totally by the proliferating gastric cancer cells, and gastric cancer cells formed cell cluster type metastasis. But the proliferating cancer cells weren't observed in non-milky spot areas at the same stage, and cancer cells formed single cell type metastasis. Conclusion Cancer cells selectively infiltrate into the milky spots at the early stages of peritoneal cancer dissemination; the cell cluster type metastasis in milky spots becomes a main cell source of further peritoneal metastasis. Key words: Castric carcinoma; Peritoneum; Metastasis; Milky spot