PTK6 and cancer: In the prostate cancer, PTK6 is expressed only in a portion of cancer epithelial cells (Fig. 5A, green and purple cell populations), while SRC is more broadly distributed in epithelial cells and other cell populations, such as immune cells (pink, light-orange), fibroblasts (blue), perivascular (light-green), and endothelial cells (orange) (Fig. 5A, other cell populations colors not labeled) (45).