The spread of cancer cells in the body -'metastasis,' is a challenging issue for cancer patients and for cancer research. From a clinical point of view, the majority of the cancer-related deaths in patients who suffer from solid cancers are metastasis-related. Although this life threatening consequence in cancer is recognised almost immediately at the time of diagnosis, the current-state-of-knowledge on the mechanisms and effective ways to combat cancer metastasis in clinical settings is far from being realized. Thus, making the necessity of continuing research into cancer metastasis evermore demanding and critical. This issue of the journal is directed toward consideration of some of the salient aspects of cancer metastasis, with a focus on recent progress of the molecular and cellular mechanisms of cancer invasion and metastasis.