The Carcinogenicity of Compounds Related to

SUMMARY 1.Thecarcinogenicactivitiesoffourteencornpoundsstructurally related to%-@acetylaminofluoreneandwhichdifferprincipallyinthenatureofthebridgesbetweenthetwoaromaticringshavebeendeterminedintherat.Thesecompoundsarethe%-acetylaminoderivatives of9-fluorenol,9-fluorenone, phenanthrene, 9,10-dihydrophenanthrene,carbazole,pyrene,anddibenzothiophene;the3-acetylaminoderivatives ofphenanthrene, carbazole, dibenzothiophene sulfone, and di phenylmethane; the4-acetylaminoderivativesofdiphenylsuffideandbiphenyl;and1-acetylaminopyrene. %.%-Acetylaminofiuorene induced high mci dencesoflivertumorsinthemalesandofmarnmaryglandtumorsinthefemalesandmoderateincidencesoftumorsoftheearductandsmallintestinalepitheliuminbothsexes.3.Afluorenenucleusappearstoberequiredforstrongcarcinogenicactivitytowardtheliver.2-Acetylamino-9-fluorenoland%-acetylamino-9-fiuorenonehadweakactivity;theothercompoundswereinactive.4.Abiphenylnucleusisapparentlynecessaryforcarcinogenicactivitytowardthemammarygland.4-Acetylaminobiphenyl wasasactiveas%-acetylaminofiuorene, andanumberofcompoundswithbridgesinthe%,%‘-positionswerealsoactive.5.Therequirements forcarcinogenicity towardtheearductandintestinalepitheliumwereintermediatebetweenthoseoftheliverandmammarygland;ingeneral,atricyclicderivativewasnecessary.6.%-Acetylaminophenanthrene, inadditiontoinducingtumorsofthemammary gland,earduct,andintestinalepithelium, alsohadamoderateleukemogenicactivity.Whenfedathigherlevels,itinducedaparalysisofthehindlimbs.