title: The response of a human tumour xenograft to chemotherapy: intrinsic variation between tumours and its significance in planning experiments.
abstract: The HT29R human colon adenocarcinoma cell line has been used to investigate the problem of inter-tumour variability in the xenograft system and how this may affect the planning of chemotherapy experiments. Subcutaneous inoculation of 10(6) in vitro cells into immuno-suppressed mice yielded an 80% take rate of moderately poorly differentiated, mucin-secreting tumours with a mean doubling time of 6 days. Statistical estimates from experiments with this system demonstrated that whereas a delay of one doubling time in treated compared with control groups could be detected with relatively small animal numbers, 3 to 4 times as many animals were needed to detect a delay of half a doubling time. The use of 2 tumours per animal yielded the same results as one tumour per animal but reduced the number of animals needed to achieve the same degree of statistical significance.
mesh_terms: D000230:Adenocarcinoma / Q000188:drug therapy* / Q000473:pathology; D000818:Animals; D002460:Cell Line; D003110:Colonic Neoplasms / Q000188:drug therapy* / Q000473:pathology; D003520:Cyclophosphamide / Q000627:therapeutic use; D006801:Humans; D008297:Male; D051379:Mice; D008808:Mice, Inbred CBA; D009368:Neoplasm Transplantation; D009374:Neoplasms, Experimental / Q000188:drug therapy / Q000473:pathology; D012107:Research Design; D013997:Time Factors; D014183:Transplantation, Heterologous
chemical_list: D003520:Cyclophosphamide