TP53 and lung cancer: Indeed, measurement of track lengths of replicating DNA fibers (14, 30, 31) from isogenic mock-depleted (shGFP) or Onc-p53-depleted (shp53) H1975 (p53-R273H) human lung cancer cells (Fig. 1A) revealed shorter track lengths (Fig. 1B,C) and shorter inter-origin distances between contiguous origins (Fig. 1D,E) in shGFP H1975 cells in comparison to shp53 H1975 cells.