Under agarose, Transwell, and μ-slide assays (Figure 3), either using ex vivo conditioned medium of T cells from the invasive margin or knocking out CCL5 in T cells in a colorectal cancer mouse model bearing liver metastases and monitoring cancer cell migration to the invasive margin through intravital microscopy (Figure 4) would demonstrate in vitro whether CCL5 produced by T cells promotes cancer cell chemotaxis to invasive margins. The gene discussed is CCL5; the disease is colorectal cancer.