MKI67 and neoplasm: Of note, we did not observe significant effects exerted by MTD or LDM chemotherapy regimens upon Ki67 per se (Fig 1D), although the mean proliferative index in all tumors was 29.2% [range: 7.6–89.5%; n = 29], consistent with our observations of similar primary tumor volumes, thereby expected to result in similar O2 diffusion distances and hence hypoxic fractions.