Table 5.
Incidences of selected nonneoplastic and neoplastic lesions in B6C3F1 mice exposed to benzophenone in feed for 2 years
| 0 ppm | 312 ppm | 625 ppm | 1,250 ppm | |
|---|---|---|---|---|
| Males | ||||
|
| ||||
| Number Examined | 50 | 50 | 50 | 50 |
| Kidney | ||||
| Nephropathy a | 49 (1.2) b | 48 (1.4)▲ | 50 (1.7)▲ | 50 (3.0) ▲ |
| Cortex, Cyst | 4 | 8 | 12* | 22** |
| Nose | ||||
| Olfactory Epithelium, Metaplasia | 0 | 2 (1.0) | 2 (1.0) | 24** (1.2) |
| Spleen | ||||
| Lymphoid Follicle Hyperplasia, Lymphoid | 17 (2.1) | 31** (2.5) | 34** (2.0) | 32** (2.2) |
| Testes | ||||
| Mineralization | 0 | 1 (1.0) | 4 (1.0) | 12** (1.1) |
|
| ||||
| Females | ||||
|
| ||||
| Number Examined | 50 | 50 | 50 | 50 |
| Histiocytic Sarcoma c | 0 | 0 | 5* | 3 |
| Kidney | ||||
| Nephropathy | 21 (1.2) | 33** (1.1) | 31* (1.5) | 30* (1.7) ▲ |
| Mineralization | 0 | 1 (1.0) | 4 (1.0) | 12** (1.1) |
| Nose | ||||
| Olfactory Epithelium, Metaplasia | 0 | 0 | 0 | 39** (1.7) |
| Spleen | ||||
| Hematopoietic Cell Proliferation | 16 (2.6) | 35** (2.1) | 32** (2.4) | 27* (2.8) |
| Lymphoid Follicle, Hyperplasia, Lymphoid | 24 (2.5) | 36** (2.5) | 37** (2.7) | 22 (2.9) |
*
Significantly different (p ≤ 0.05) from the control group by the Poly-3 test
**
p ≤ 0.01
▲
Significantly different severity (p≤ 0.05) from the control group by the Mann-Whitney U test
a
Number of animals with lesions
b
Average severity grade of lesions in affected animals: 1=minimal, 2=mild, 3=moderate, 4=marked
c
Historical incidence for 2-year studies with feed controls, given NTP-2000 diet (mean ± standard deviation): 2/459 (0.3% ± 0.8%), range 0%–2%; all routes 18/1,258 (1.5% ± 2.2%), range 0%–8%