Table 2.
Time to tumor formation (tumor latency) of 3 different lots of MDCK cells in adult athymic nude mice
| Average time (wk) to appearance of tumors at indicated cell doses (log10) |
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| Experiment no. | 7 | 6 | 5 | 4 | Meana | Average mean | |
| Vial 1 | 1 | 1.4 | 10.8 | 14.1 | ND | 8.8 | 6.6 |
| 2 | 2.0 | 7.9 | 11.5 | ND | 7.1 | ||
| 3 | 1.0 | 4.5 | 7.6 | ND | 4.4 | ||
| 4 | 1.5 | 7.8 | 14.0 | ND | 7.8 | ||
| 5 | 1.6 | 7.5 | 6.0 | ND | 5.0 | ||
| Mean (range) | 1.5 (1–2) | 7. 7 (3–25) | 10.6 (7–26) | not done | |||
| Vial 2 | 1 | 1.0 | 1.6 | 2.8 | 7.5 | 3.2 | 2.9 |
| 2 | 1.0 | 1.7 | 3.8 | ND | 2.2 | ||
| 3 | 1.0 | 2.0 | 4.4 | 6.0 | 3.4 | ||
| Mean (range) | 1.0 (1) | 1.8 (1–3) | 3.7 (2–4) | 6.8 (5–9) | |||
| Vial 3 | 1 | 1.2 | 6.3 | ND | ND | 3.8 | not applicable |
ND, not determined due to the absence of tumors at the indicated cell dose
The difference in average mean tumor latency between vials 1 and 2 is statistically significant (P = 0.0043).