The use of genetic polymorphisms for identification of fused cells

Abstract: Metastasis is a feared aspect of cancer and little is known about the underlying mechanisms. It is proposed that metastasis is caused by cell fusion between tumour and immune active phagocyte cells, for example macrophages. Such hybrid cells could then develop immortality and chemo tactic mobility. In two different systems it was examined whether it is possible to detect variation in cancer cells that would explain an initial fusion between tumour cells and leukocyte cells. Both systems included use of STR markers. Human colon carcinoma cells, which originally had been grown in nude mice, were investigated with mouse specific primers. These showed no trace of mouse DNA, which they most probably would have if cell fusion had occurred. Human breast cancer cells grown in nude mice, that had received injection of stem cell from male blood, showed no presence of Y-chromosomes. Blood, which was analyzed from one of the mice, showed a weak presence of something else than just mouse DNA. The result was however vague and hard to evaluate, and tries to reproduce the positive outcome failed. No evidence, which indicated that cell fusion occurred, was possible to demonstrate. On the other hand, there are previous studies that show how metastases can express macrophage specific properties, which gives all reason for further investigations.