N-nitroso-n-methylurea: Carcinogenic Potency Database

N-Nitroso-N-methylurea (CAS 684-93-5)
SMILES, InChI and Structure are below.
Rats and Mice: Cancer Test Summary

Rat Target Sites		Mouse Target Sites		TD₅₀ (mg/kg/day)
Male	Female	Male	Female	Rat	Mouse
lun nrv sto	no test	sto vsc	no test	0.0927	1.23

Monkeys: Cancer Test Summary

Monkey Target Sites		TD₅₀ (mg/kg/day)
Rhesus	Cynomulgus	Rhesus	Cynomulgus
eso	eso	7.18	4.52

Key to the Table Above

Positivity: For each chemical with a positive (carcinogenic) experiment in the Carcinogenic Potency Database (CPDB), results are included on carcinogenic potency (TD₅₀) in each species and target sites in males and females. Positivity is determined by an author’s opinion in a published paper. If all experimental results in the CDPB are negative in a sex-species group, “no positive” appears. If the CPDB has no experiments in the sex-species group, “no test” appears. The summary presents the strongest evidence of carcinogenicity in each group. If there are both positive and negative experiments in a sex-species, the negative results are ignored in this Summary Table.

Target Site Codes: eso = esophagus. lun = lung. nrv = nervous system. sto = stomach. vsc = vascular system. Target sites are listed if any author of published experimental results concluded that tumors were induced in that organ by the test agent. If there is more than one positive experiment in a sex-species, target sites listed may be from more than one experiment, e.g. if liver and lung are both listed, then liver may have been a target in one experiment and lung in another.

TD₅₀: Our standardized measure of carcinogenic potency, TD₅₀, is the daily dose rate in mg/kg body weight/day to induce tumors in half of test animals that would have remained tumor-free at zero dose. Whenever there is more than one positive experiment in a species, the reported TD₅₀ value is a Harmonic Mean calculated using the TD₅₀ value from the most potent target site in each positive experiment.

The Carcinogenic Potency Database (CPDB) is a unique and widely used international resource of the results of 6540 chronic, long-term animal cancer tests on 1547 chemicals. The CPDB provides easy access to the bioassay literature, with qualitative and quantitative analyses of both positive and negative experiments that have been published over the past 50 years in the general literature through 2001 and by the National Cancer Institute/National Toxicology Program through 2004. The CPDB standardizes the diverse literature of cancer bioassays that vary widely in protocol, histopathological examination and nomenclature, and in the published author’s choices of what information to provide in their papers. Results are reported in the CPDB for tests in rats, mice, hamsters, dogs, and nonhuman primates.

For each experiment, information is included on species, strain, and sex of test animal; features of experimental protocol such as route of administration, duration of dosing, dose level(s) in mg/kg body weight/day, and duration of experiment; experimental results are provided on target organ, tumor type, and tumor incidence; carcinogenic potency (TD₅₀) and its statistical significance; shape of the dose-response, author’s opinion as to carcinogenicity, and literature citation.

Only tests with dosing for at least ¼ the standard lifespan of the species and experiment length at least ½ the lifespan are included in the CPDB. Only routes of administration with whole body exposure are included. Doses are standardized, average dose rates in mg/kg/day. A description of methods used in the CPDB to standardize the diverse literature of animal cancer tests is presented for: 1) Criteria for inclusion of experiments 2) Standardization of average daily dose levels and 3) TD₅₀ estimation for a standard lifespan. See Methods for other details.

TD₅₀ provides a standardized quantitative measure that can be used for comparisons and analyses of many issues in carcinogenesis. The range of TD₅₀ values across chemicals that are rodent carcinogens is more than 100 million-fold. More than half the chemicals tested are positive in at least one experiment.

A plot of all results on each experiment in the CPDB for this chemical is presented below. These results are the source information for the Cancer Test Summary table above.

N-Nitroso-N-methylurea: All Experiments and Citations in CPDB

The definition of each code in the plot below will appear in a pop-up window when the field name in the header line is clicked, e.g., Strain, Site, Path. Each numbered line starts a new experiment and reports protocol information in black. Average daily dose-rates per kg body weight per day are in green. Remaining lines report experimental results in blue.

Abbreviations of fields in header line: # = the line number in the plot of all CPDB chemicals; Xpo = duration of dosing; Xpt = duration of experiment; Site = tissue; Path = tumor type; DR = dose-response; AuOp = author’s opinion about carcinogenicity; LoConf, UpConf = confidence limits (99%) on TD₅₀; Inc = tumor incidence for each dose group.

See Guide to reading the plot for details on each field, using an example of one experiment.

See Help to improve readability, or to fit the plot onto the screen or a printed page.



Chemical (Synonym) CAS
# Species Sex Strain Route Xpo+Xpt PaperNum        0 Dose  1 Dose 2 Dose  3 Dose          Literature Reference or NCI/NTP:Site Path
Site Path Notes   TD50  DR Pval    AuOp LoConf UpConf   Cntrl   1 Inc  2 Inc   3 Inc                                                        Brkly Code



N-NITROSO-N-METHYLUREA   684-93-5
4449 M m c3h wat 30w54 2182                          0    2.78mg  5.56mg  11.1mg         Tatematsu;gann,84,1258-1264;1993/pers.comm.
 lun ade e      .794mg Z P<.003     .380mg 3.14mg   0/10   10/21   (6/21    4/22)
 spl hms e      1.23mg * P<.0005 +  .814mg 3.95mg   0/10    8/21   18/21   13/22
 stg adc e      6.19mg * P<.004  +  3.10mg 36.2mg   0/10    1/21    3/21    7/22
 liv nnd e      2.53mg Z P<.5       .538mg n.s.s.   3/10    9/21   (2/21    1/22)
 liv hpc e      no dre   P=1.       16.7mg n.s.s.   1/10    2/21    0/21    0/22
4450 P b cym eat 18y22 2004 :                        0    6.32mg           Adamson;ossc,129-156;1982/Thorgeirsson 1994/Dalgard 1997/
                                                                                                      Thorgeirsson&Seiber pers.comm.
 ugi sqc jw     4.52mg   P<.0005 +  1.22mg 18.6mg   0/63    6/16
 eso mix jw     7.71mg   P<.0005 +  2.95mg 27.9mg   0/63    6/16
 eso sqc jw     10.5mg   P<.002  +  3.75mg 46.0mg   0/63    5/16
 orc mix jw     2.65mg   P<.04      .652mg n.s.s.   0/4     2/2
 phr sqc jw     82.2mg   P<.08      13.4mg n.s.s.   0/63    1/16
 pls sqc jw     7.95mg   P<.2       1.29mg n.s.s.   0/4     1/2
 ton sqp jw     7.95mg   P<.2       1.29mg n.s.s.   0/4     1/2
 sku rhb jw     23.9mg   P<.2       3.88mg n.s.s.   0/10    1/5
 eso sqp jw     29.2mg   P<.2       4.75mg n.s.s.   0/12    1/6
 col lei jw     34.5mg   P<.2       5.61mg n.s.s.   0/14    1/7
 hea rhm jw     66.3mg   P<.2       10.8mg n.s.s.   0/26    1/13
 sto adc jw     66.3mg   P<.2       10.8mg n.s.s.   0/26    1/13
 tba mix jw     2.64mg   P<.005     .839mg 35.0mg   4/63    9/16
 tba mal jw     4.00mg   P<.02      1.26mg n.s.s.   3/63    7/16
 tba ben jw     19.1mg   P<.5       2.14mg n.s.s.   2/20    2/8
4451 P b rhe eat 18y22 2004 :                        0    7.80mg
 ugi sqc jw     7.18mg   P<.0005 +  3.23mg 21.0mg   1/72    9/16
 eso sqc jw     8.20mg   P<.0005 +  3.58mg 22.4mg   0/72    8/16
 orc mix jw     15.7mg   P<.003     4.90mg 143.mg   1/72    4/16
 phr sqc jw     44.2mg   P<.008     10.8mg 1.52gm   0/72    2/15
 epg sqc jw     42.8mg   P<.06      6.98mg n.s.s.   0/37    1/7
 sto adc jw     42.8mg   P<.06      6.98mg n.s.s.   0/37    1/7
 gnv sqc jw     62.6mg   P<.07      10.2mg n.s.s.   0/47    1/10
 lar sqc jw     95.6mg   P<.07      15.6mg n.s.s.   0/72    1/15
 chp sqc jw     95.6mg   P<.07      15.6mg n.s.s.   0/72    1/15
 pls sqc jw     102.mg   P<.07      16.6mg n.s.s.   0/72    1/16
 ton sqc jw     72.9mg   P<.3       8.84mg n.s.s.   1/72    1/16
 tba mal Wjw    6.75mg   P<.0005    2.79mg 26.2mg   5/74    9/16
4452 R m f34 gav  6m24 1915                          0    .312mg                                        Lijinsky;txih,5,925-935;1989
 for tum        92.7ug   P<.0005 +  44.1ug .203mg   0/12   18/20
 lun mix        .357mg   P<.002  +  .165mg 1.33mg   0/12    9/20
 ner mix        2.03mg   P<.2    +  .498mg n.s.s.   0/12    2/20
 liv tum        11.6mg   P<.9       .574mg n.s.s.   1/12    2/20

Mutagenicity in Salmonella: positive
SMILES Code for N-Nitroso-N-methylurea: CN(C(=O)N)N=O
InChI Code for N-Nitroso-N-methylurea: InChI=1/C2H5N3O2/c1-5(4-7)2(3)6/h1H3,(H2,3,6)
Source for SMILES and InChI: USEPA Distributed Structure-Searchable Toxicity (DSSTox) Database

Chemical Structure for N-Nitroso-N-methylurea:

Source for structure: National Library of Medicine ChemIDPlus

See full CPDB Summary Table on 1547 chemicals. See Full CPDB for all results on 6540 experiments of 1547 chemicals.

A complete list of CPDB chemicals, which is searchable by name or by CAS number, is available here.

For a compendium of CPDB results organized by target organ, which lists all chemicals in each species that induced tumors in each of 35 organs, see Summary Table by Target Organ.

The CPDB is available in several formats that permit printing and downloading into spreadsheets and statistical databases.

A plot of the CPDB presents results of 1547 experiments on 6540 chemicals in an easily readable format that has been used in publications of the CPDB.
A Screen version plot for use on a single computer screen, with the same data.
Excel version of the same data.
Tab-separated versions of the same data, which can be easily read into databases.

A Supplementary Dataset gives details on dosing and survival for each experiment.

Relatively precise estimates of the lower confidence limit on the TD₁₀ (LTD₁₀) are readily calculated from the TD₅₀ and its lower confidence limit, which are reported in the CPDB. For researchers and regulatory agencies interested in LTD₁₀ values, we provide them in an Excel spreadsheet.

PDF versions of our publications of analyses using the CPDB are available, organized by year and by research topic.

Carcinogenic Potency Database Project (CPDB) Home Page
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Last updated: October 3, 2007