Experimental analysis of the metastatic phenotype of malignant leukocytes

The metastatic phenotype (M+) is determined by the expression of the invasive (I+) and growth (G+) phenotypes at various sites along the metastatic pathway. The G, I and M phenotypes are not confined to tumor cells and may be expressed by normal cells, such as leukocytes, under certain physiological conditions. The study of the I and M phenotypes of leukocytes may yield valuable information on common mechanisms, underlying invasion and metastasis of normal and malignant cells. In this review we summarize experimental approaches that were developed for the analysis of the I and M phenotypes of normal and malignant leukocytes.