Novel frontiers in detecting cancer metastasis.

Cancer microenvironment is the critical battle ground between the cancer cells and host response. Thus, more emphasis is directed to study the relationship between cancer cells and the stromal cells. Multiplex microscopy is an emerging technique in which multiple cell populations within the cancer microenvironment may be stained so that spatial relationship between cancer cells and, in particular, the immune cells may be studied during different stages of cancer development. Recent discovery of mutational burden and neoantigens in cancer has opened new landscapes in the interaction of host immune cells and cancer neoantigens. The emerging role of miRNAs may become an added dimension to study cancer beyond traditional pathway of DNA directed RNA being associated with the malignant behavior of cancer. Circulating tumor cells, cancer markers and ctDNA can be used as markers for circulating cancer cells in the blood. Further studies are needed to validate if liquid biopsy of cancer may become a routine clinical tool to screen cancer or follow patients for recurrence or responses to treatment.