Table 3.
Incidence of neoplastic lesions and statistical analysis results derived from male and female F344/N rats and male F344/N Nctre rats from 2‐year carcinogenicity assays with furan
| Lesiona | Dosage (mg/kg bw per day) | Incidenceb | Reference | |
|---|---|---|---|---|
| Male | Female | |||
| Cholangiocarcinoma before re‐evaluationc |
0 2 4 8 |
0/50 43/50*** 48/50*** 49/50*** |
0/50 49/50*** 50/50*** 48/50*** |
NTP (1993), Maronpot et al. (1991) |
| Hepatocellular adenoma/carcinoma |
0 2 4 8 |
1/50 5/50 22/50*** 35/50*** |
0/50 2/50 4/50 8/50** |
NTP (1993) |
| Interstitial cell adenoma of testesd |
0 2 4 8 |
41/50 36/50 39/50 43/50 |
NTP (1993) | |
| Hepatocellular carcinoma |
0 2 4 8 |
0/50 1/50 6/50* 18/50*** |
0/50 0/50 0/50 1/50 |
Maronpot et al. (1991) |
| Hepatocellular adenoma |
0 2 4 8 |
1/50 4/50 18/50*** 27/50*** |
0/50 2/50 4/50 7/50** |
Maronpot et al. (1991) |
| Mononuclear cell leukaemia |
0 2 4 8 |
8/50 11/50 17/50* 25/50*** |
8/50 9/50 17/50* 21/50** |
NTP (1993) |
| Malignant mesothelioma |
0 2 4 8 |
1/50 1/50 3/50 3/50 |
– | NTP (1993) |
| Mononuclear cell leukaemia |
0 0.02 0.044 0.092 0.2 0.44 0.92 2 |
47/150 56/150 36/100 44/100* 29/50*** 18/50 27/50*** 28/50*** |
– | NCTR (2015) |
| Malignant mesothelioma of the tunica vaginalis |
0 0.02 0.044 0.092 0.2 0.44 0.92 2 |
6/150 8/150 1/100 2/100 0/50 2/50 2/50 6/50* |
– | NCTR (2015) |
| Follicular cell adenoma |
0 0.02 0.044 0.092 0.2 0.44 0.92 2 |
0/150 2/150 5/99 0/100 1/50 1/49 0/50 0/50 |
– | NCTR (2015) |
| C‐cell adenoma |
0 0.02 0.044 0.092 0.2 0.44 0.92 2 |
11/150 15/150 9/99 13/100 7/50 8/49 1/50 8/50* |
– | NCTR (2015) |
| C‐cell adenoma or carcinoma |
0 0.02 0.044 0.092 0.2 0.44 0.92 2 |
12/150 21/150 11/99 14/100 8/50 9/49 1/50 9/50* |
– | NCTR (2015) |
bw: body weight.
Only the major tumour sites and/or those showing significant effects at the lower dose are listed.
*Equals significant at > 0.05; **equals significant at > 0.01; ***equals significant at > 0.001.
Re‐examination of 23 of these samples at a later date revealed that only in the highest dose cholangiocarcinomas were present.
This was the terminology used in the paper, however, this is equivalent to mesotheliomas of the tunica vaginalis
Von Tungeln et al. (2017) specified that the F344/N NCTR substrain differs from the Charles River substrain used in the previous furan bioassay (NTP, 1993). However, the NCTR F344/N sub‐strain has tumourigenic responses that are comparable to those of other F344/N substrains used in previously reported carcinogenicity bioassays such as acrylamide.