TP53 and neoplasm: Treatment with 1 μM U18666A for 18 h induced growth cone collapse in about 80% of hippocampal neurons prepared from wild-type mice and transfected with an EGFP-vector or a vector containing p53 with the R175H mutation (a conformational mutation that is frequently found in tumor cells, resulting in lack of p53 function) (Fig. 1D&E).