Inflammatory cells in 256 Walker tumour growing in the stomachs of rats.

The present study was undertaken in order to determine the relative number of inflammatory cells in Walker 256 tumour implanted in the gastric mucosa of the rat. Inflammatory cells were found in all tumours, the relative content ranging from 5-21 (mean 12%), which is comparable to findings in human intestinal tumours. Approximately 80% of the inflammatory cells were mononuclear (lymphocytes, plasma cells and macrophages); less than 20% were polymorphonuclear (neutrophils and eosinophils). Both the number of inflammatory cells and the composition of the cell infiltrates changed during the tumour growth. The highest proportion was found on day 6 after implantation. In addition to the inflammatory cells within the tumor parenchyma, a large number of inflammatory cells were found in the tumour stroma. Possible mechanisms for the inflammatory cell reaction within and around the experimental tumours are discussed.