[Stromal changes in cancer. Studies on changes of stroma promoted by gastric cancerous cells using alginate microcapsules].

Xenografting can be accomplished by using encapsulated cells in the alginate microcapsule. Using this technique, the experiment was made to investigate the stroma-promoting factors that were produced by the encapsulated differentiated (MKN-28) and undifferentiated (KATO-III) gastric cancerous cell lines. Fibronectin (FN) in the medium was quantified by single culture with the human fibroblast cell line (CCD-32Lu) and coculture with CCD-32Lu and the encapsulated MKN-28 ro KATO-III. Then following this procedure, each capsule including the gastric cancerous cells was subcutaneously transplanted into Wistar Rats. After 14 days, the surrounding tissues of the microcapsules were stained, and the localization of type III collagen, 4 and 6 chondroitin sulfate, and FN were observed by immunohistochemical stainings. The concentration of FN in both single culture and coculture medium gradually increased, especially in the medium complemented with KATO-III and CCD-32Lu. The measured point after 48 hours demonstrated the obvious increase compared to the single culture and coculture medium. Upon the histological comparison, it was found that the stromal proliferation around the tissue transplanted the microcapsules including MKN-28 or KATO-III were distributed more abundantly than the transplantation of microcapsules only. However, no difference was noted between the stroma of MNK-28 and KATO-III. In conclusion, this study suggests that any stroma-promoting factor is produced by the gastric cancerous cells.