NEFH and neoplasm: Compared to the control, the F3.CD-TK-treated spinal cords had significantly increased group average IRL values of neurofilament H (NF-H), a mature neuronal marker [29], in the host neurites (i.e., DiI−); these neurites ran through the grooved/indented tumor periphery that interfaced with C7 dorsolateral parenchyma, around Rexed lamina-I (RL-I; n = 6/group; p < 0.01, Student’s t-test; Figure 6A–C).