Organ selectivity in human cancer metastasis. A review

Organ selectivity, although a widely acknowledged feature of human cancer metastasis, is largely unexplained. It may be defined as the secondary formation in an organ of tumor tissue which shows a peculiar pattern of localization. On reviewing the literature, twelve classes of selectivity were discernible. It was found that the adrenal gland featured in eleven of these classes. Accordingly, the prospects of explaining selective metastasis will probably improve if research is concentrated on this promising gland. Alternatively, research should be concentrated on any other organ which is shown to have a better claim to priority in this important field.