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Toxicological information

Carcinogenicity

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Description of key information

The existing two long-term studies on CBS in mice are not in accordance with current testing procedures as proposed by recent guidelines on carcinogenicity and/or combined chronic toxicity/carcinogenicity. However, they are performed in accordance with generally accepted scientific standard. The results have shown that CBS is not carcinogenic in mice at a dose of 95.3 mg/kg bw and day (time-weighted average dose).
This assessment is in line with the EU risk assessment (2007).

Key value for chemical safety assessment

Carcinogenicity: via oral route

Endpoint conclusion
Endpoint conclusion:
no adverse effect observed
Dose descriptor:
NOAEL
95.3 mg/kg bw/day
Study duration:
chronic
Species:
mouse
Quality of whole database:
Study was performed in accordance with generally accepted scientific standard.

Carcinogenicity: via inhalation route

Endpoint conclusion
Endpoint conclusion:
no study available

Carcinogenicity: via dermal route

Endpoint conclusion
Endpoint conclusion:
no study available

Additional information

Carcinogenicity: oral

Groups of 18 mice per sex of the B6C3F1 strains and the B6AK1 strains, were given 215 mg/kg bw and day CBS by repeated oral gavage for 21 days followed by exposure for nearly 17 months to diet containing CBS at a concentration equivalent to ca. 90 mg/kg bw/d (corresponding to a time weight average dose of 95.3 mg/kg bw and day. An equal number of mice served as vehicle control. Survival of the CBS-treated mice of both strains was comparable to the control group (vehicle control B6C3F1: male 16/18, females 16/18; B6AKF1 male: 18/18, female: 15/18; CBS treated B6C3F1 mice: male 16/18, females: 15/18; B6AKF1 male: 18/18, female: 17/18. No adverse effects were reported. Tumors were found in all groups but there were no statistically significant differences between CBS-treated and control mice in the incidence of the individual types of tumor. The total number of tumors was not statistically significant different in CBS-treated and control mice (vehicle control B6C3F1 mice male/female: 3/4, B6AKF1 mice male/female: 3/3; CBS treated B6C3F1 mice male/female: 8/6, CBS treated B6AKF1 mice male/female: 3/3). In summary there was no evidence of a carcinogenic effect in both strains of mice (NCI 1968).

Carcinogenicity: other route (dermal)

Groups of 18 B6C3F1 and 18 B6AKF1 mice of each sex received a single subcutaneous injection in 0.05 ml suspension (1000 mg/kg) CBS in the nape of the neck with sacrifice at ca. 17 months after injection (no more data available). An equal number of mice of each strain served as vehicle control. Survival of the CBS-treated mice was comparable to the control group in both strains. No adverse effects were reported and no statistically increase in tumor incidences were observed in mice of both strains. The total number was similar in treated and control mice (vehicle control B6C3F1 male/female mice: 4/0, B6AKF1mice male/female: 1/1; CBS treated B6C3F1 mice male/female: 3/1, CBS B6AKF1 mice male and female 0/2). In summary there was no evidence of a carcinogenic effect of CBS in both strains of mice (NCI 1968).

Justification for classification or non-classification

According to CLP classification criteria (Regulation (EC) No 1272/2008) a classification is not justified.