Table 1.
Dose–response data on the tumor-forming capacity of 3 different lots of CCL34 MDCK cells in adult athymic nude mice
| Experiment no. (passage [p] level) | Tumor incidence at indicated cell dose (log10) after subcutaneous inoculation (no. mice in which tumors formed/total no. of mice inoculated) |
TPD50a (log10) | Mean TPD50 (log10) | |||||
| 7 | 6 | 5 | 4 | 3 | ||||
| Vial 1 | 1 (p58) | 17/18b | 6/9 | 8/10 | 0/10 | not tested | 5.1 | 5.2 |
| 2 (p60) | 20/20 | 19/20 | 12/20 | not tested | not tested | 5.0 | ||
| 3 (p61) | 10/10 | 9/10b | 4/10b | 0/10 | not tested | 5.2 | ||
| 4 (p62) | 9/10b | 8/10 | 4/10 | 0/10 | not tested | 5.4 | ||
| 5 (p61) | 5/5 | 4/5 | 1/5 | 0/5 | not tested | 5.5 | ||
| Total incidence | 61/63 | 46/54 | 29/55 | 0/35 | ||||
| Vial 2 | 1 (p62) | 10/10 | 10/10 | 10/10 | 4/10 | 0/5 | 4.1 | 4.4 |
| 2 (p64) | 9/10b | 10/10 | 9/10 | 0/10 | 0/5 | 4.7 | ||
| 3 (p62) | 5/5 | 5/5 | 5/5 | 1/4 | not tested | 4.3 | ||
| Total incidence | 24/25 | 25/25 | 24/25 | 5/24 | 0/10 | |||
| Vial 3 | 1 (p61) | 10/10 | 7/10 | 0/10 | 0/10 | 0/10 | 5.8 | not applicable |
The difference between mean TPD50 values for vials 1 and 2 is significant (P = 0.0027).
a
The TPD50 represents the threshold (endpoint) cell dose required for tumor-forming activity by populations of neoplastic cells that express tumorigenic phenotypes.
b
Complete regression occurred with one tumor in these experiments.