Document jNgyD9qbmooQ0a79BgqmKQjd2

, 194 Annals New York Academy of Sciences . Popper about the reversibility of the phenomenon, particularly if caught early. If workers arc exposed to moderate to low levels for relatively short periods of time, has there been any evidence that there is any irreversible change, or does the progression that you were documenting take time? Dr. Popper: The only real experience we had was a case which Dr. Berk presented. In this case, after discontinuation of the exposure, fibrosis persisted, but other features were absent. The characteristic disturbing activation of the hepatocytes was no longer seen, I am not surprised. From experience with hepatic fibrosis in circumstances other than vinyl chloride, it is known that fibrous tissue may not disappear once present. I suspect, but do not know, that the person may be left with innocent scars <`n the liver which possibly may not interfere with his life expectancy. One - patient, however, is really no proof. Part II. Carcinogenesis associated with Vinvl Chloride A. Experimental StnilicH CARCINOGENICITY BIOASSAYS OF VINYL CHLORIDE: CURRENT RESULTS Cesarc Maltoni and Giuseppe Lefemine Istiluio di Oncologic and Centro Tumori Bologna, Italy Introduction o 8 8 Vinyl chloride (VC) has been produced in many countries for more than '30 years. It is the constituent of polyvinyl chloride (PVC), which nowadays is the plastic industrial material most used and diffused in the world. Moreover, it is used as a copolymer in Saran and other plaslics. as a chemical intermediate, as a solvent, and as a propellant: in the past, tor a short period, it was also used as an anesthetic. VC is at present produced at a rate of near 12 million tons per year. The following population groups may be exposed to VC: (1) workers engaged in the production of PVC and oi V'C anti in the use of VC tor other industrial I purposes; (2) workers manufacturing PVC, (3) residents in areas neighboring on factories producing PVC and VC: and to a much lesser extent (4) people using products containing VC, as some propellent sprays; (f) people having contact with resins made with VC and with materials containing these resins: and (6) populations consuming food contained in plastics made with VC. Bioassays on the long term effects of VC wbre not a\unable until 1970. This situation reflects the limned consideration which has been, up to the | present, given to experimental bioassavs in predicting the oncogenic clfects on man of environmental and occupational agents. In part this is due to industrial I and economical interests, in part to deficiencies in technical-scientific facilities, to the dilettantism of many experimental workers, and to the inadequacy ot many i experiments pcrlormcd in the past. i What is now happening with vinyl chloride and the story of vinyl chloride 1 carcinogenicity should bring about greater consideration of experimental bioas says and finally induce a new turn in the field oi occupational and environmental carcinogenesis. In other words, experimental prediction on the pathogenetic potential of occupational and environmental agents before they are produced and released on a targe scale into the human environment should preclude the need for later epidemiological evidence. $ History cv In 1970 Professor Viola presented, at the X International Cancer Congress (Houston), the results of a pilot experiment, which then were extensively pub lished in 1971.' Professor Viola reported to have observed in 26 rats exposed by inhalatory route to 30,000 ppm of VC 4 h daily, 5 days weekly, for 10-12 months, surviving 10 months or more, 17 skin tumors, 7 pi nary tumors, mainly carcinomas, and 5 osteochondromas. New York Acuuctny oi Sciences In 1967 our Institute started a large investigation, among workers of several ' Italian industrial plants, to determine the cITccis of the exposure to different .chemicals on respiratory cpithcliu. The pathological changes were studied by sputum cytology. In 1970 this research was extended also to workers in VC-PVC ., industries. A significant increase of cellular changes in bronchial epithelium, such as marked squamous metaplasia and squamous dysplasia, were found among ' the workers more heavily exposed to VC. Immediately after the Houston Congress, wc contacted I'rolcssor Viola who kindly put some slides of his experimental tumors at our disposal. According to our interpretation, the malignant tumors observed by Professor Viola in the skin were carcinomas arising from the Zymbal gland (a sebaceous gland of the ex terior acoustic duct}, which is responsive to a large number of carcinogens. The malignancies of the lung, in our opinion, were metastuscs from Zymbal gland tumors. At that time (end of 1970) wc planned a project of correlated investigations : to further clarify the type and degree of the carcinogenic risk from VC. The project was encouraged and supported by Montedison (Italy), which later was joined by other major European companies, that is, ICI (U.K.), Solvay (Belgium), and Rhone-Progil (France). The Head of the Health Services of Montedison supplied us with all the technical data dealing with occupational exposure: this made possible the repro duction in our experiments of the most important parameters of occupational conditions. Planning, Materials, and Methods This project included a series of experiments, which were started in sequence. They were designed to study the etlccts of VC, administered through dilTcrcnt routes (inhalation, ingestion, and peritoneal and subcutaneous injection), at dilTer- ent concentrations, for varying periods of lime, bv continuous or intermittent treatment, on animals of different species irats, mice, hamstcrsl. strains (Sprague- Dawlev and Wistar rats), sex and age ladults, newborns, embrvos). The planning of the program and the preparation of suitable experimental conditions, particularly the building of an apparatus lor inhalatory exposure, took us until May 1971. In July 1971 we started experimenting. The chambers of exposure are built basically of stainless steel and glass. They have been ^designed to deliver concentrations varying from 30.000 to I ppm of VC, and to treat simultaneously nearly 1,500 rodents. The VC concentration in the chambers.is controlled bv gas chromatography. The VC is supplied by Montedison. Each stock :s analyzed in the Montedison Research Unit. The impurities and their maximal levels in the VC employed have been as follows: H,0 Acetic aldehyde Acetylene IDO ppm 5 ppm 2 ppm jg .9 t0o-J -OAj Aliens Butane 1 ,3-Dutadiene Chlorophene Diacctvlene Vinyl acetylene Propine Methyl chloride 5 ppm 8 ppm 10 ppm 10 ppm 4 ppm 10 ppm 3 ppm 100 ppm Maltorii &. Lcfemine: Carcinogenicity Bioassays 197 The experiment utilized mainly Spraguc-Dawlcy rats; Wistar rats^^iss mice, and hamsiers have also been used. All the animals, except the hamsters, arc bred in our Institute for years and. whatever their use. arc all examined at death by com plete autopsy, giving us extensive information concerning their current pathology. The animals have been weaned and classified by sex when 4-5 weeks old, at which time they have been numbered by ear punch and divided into groups by litter distribution. From weaning, the animals have been fed, ad libitum, an adequate commercial diet. During the period of treatment, the animals are housed in groups of 10 in stainless stcei wire cages with a solid bottom of The same metal. After the period of experimental treatment, the animals arc kept in groups of 5 in makrolon cages, with tops made oi stJin I ess steel wire. A shallowlayer of white wood shavings serves as bedding. The animals arc kept in a temperature-controlled laboratory at 19-20'C. Fifteen experiments have been started in sequence. Sonic of them were pro grammed at the beginning; lor some others the need appeared on the basis of the first experimental results. The plan of the experiments and the up-to-date situa tion is show n in Taiile 1. Experiment / studies the effect of the atmospheric exposure to 10.000. 6,000. 2,500, 500, 250, 50 ppm of VC. 4 h daily, 5 days weekly, for 12 months. Two groups of animals were added as control: one untreated, as for all the following experiments, and one treated with vinyl acetate (VA) at 2.500 ppm, under the same conditimis. This dose of VA appeared to be the maximum possible dose for a chronic exposure. Experiment 2 was performed to investigate in a larger number of animals the effect of doses between 250 to 50, that is 200, 150 and 100, under the same con ditions as in Experiment I. It was started after it was clear that a dose of 250 ppm was still show ing oncogenic effects. Expcntticnt .1 was planned to study the effects of a shorter period of exposure, keeping all the other conditions of Experiment I. Experiment 4 studies the effects ot the same type ot exposure as in Experi ment I in another species Imice). The treatment iasted 7 months in consideration of the higher mortality and the shorter life span of the mice of our line as com pared with rats. Experiment 5 was undertaken as a pilot investigation on the possible elfecls of the atmospheric exposure, during pregnancy, on offspring. Experiment ft was planned to reproduce the same conditions as in Professor Viola's experiments. Experiment 7 was planned to study the effects of the same type of exposure as in Experiment 1 in another strain of rats (Wistar). Experiment S studies the ellccts ot the same exposure as in Experiment I. in a third species i hamsters) for the same period as in Experiment 4. Experiment 9 was planned, before tumors were observed at 50 ppm in experi ment BTI. to assess further whether inhalation ot VC has any ctfect at a dose level of 50 ppm. Experiment iO studies whether a high, hut limited and/or intermittent at mospheric exposure has any cflect. Experiment II wav per termed to evaluate the effects of VC by ingestion. Experiment /.' studies the third general route of exposure. Expetiment /.! was started to assess whether VC acts on tissues directly or through metabolites. Experiment 14 has been included to study the responsiveness ot newborns. BT1 012 DT3 DM w BT5 016 BT7 Bit 819 TahLE 1 Plan of hie Experiments up to May 5, 1974 \ooo Roult Treatment ' fJdH} of VC Length Specirs .Strain Inhalation Inhalation Inhalation Inhalation Transplucen* t.il Inhalation Inhalation Inhalation Inhalation 10 O'M). 6.000, 2,500. 500, 250, 50 ppm Untreated vontiols Treated rontroli: VA 2 MM) jM'HI 2|M). 150. 100 rpi UnircaU-il controls 10,(100, 6.000, 2,500, Mm). 250, 50 ppm Untreated coittroli lu,i)00, 6,000, 2.500, 500. 2!. 50 ppm Untreated controls lU.ooo, 6.1)00 I>pm 30 000 ppm lOI'r.K). o.OOO. 2,500. 501). 250. 50 ppm Untreated control* 10,titK), 6.000, 2.500. 500. 250, 50 pf-m Untreated controls 50 ppm Untreated controls 4 h daily, 5 days weekly. It at 52 k 4 h daily, 5 days weekly, 52 wk 4 h daily, 5 days weekly, 17 *k It a I Rat 4 h daily, 5 days weekly, Mouse weekly, 30 wk 4 h daily. ? days (from I2ih n> IBili dj> of pregnancy) 4 h daily, 5 days weekly, 52 wk 4 U daily, ) days weekly, 52 k K.u Hat Rat 4 h daily. 5 days weekly, Hamster 30 wk 4 h daily. 5 days weekly. Rat 52 wk SpragueHawley Sprat',ucDjwlty SpragueHawley Swiss SpragueDawley SpragueDawley Wistar Golden Sprague* Dawley Animals (weeks) 13 7 268 No. <? Total 309 377 Length of the Experiments st the Present Date '.weeks) Per 64-96 (Ended) !> b S3 Vi ^ 13 280 263 545 120-185 21 262 288 550 60-190 43 6* J1 250 260 510 60-150 43 o n * > S Cm | 19 (breeders) 110 36 146 30-54 77 M 12 days (cm- n bryos) o 17 30 30 60 60 43 n Vi ii -- 220 220 30-40 43 ii -- 26S 26B 32-70 30 It 200 200 400 100 (c) 300 (0 15 BTIO btii BT12 BT13 HTI4 OTIS Inhalatioo Ingestion Endopvntoncal injection Subcutaneous injection Inhalation Inhnhima 10,000, 6.000 ppm Untreated controls 16 6, 33 2* 50 mg/kg body weight in olive oil Controls, olive oil 4 25 mg in I 0 cc oluc oil Controls; 1.0 cc olive oil 4 23 mg In t 0 cc olive oil Controls; 1 0 cCr olive oil 10.000, 6.000 ppm 23, 10, 5 ppm Untreated controls 4 h daily, 5 days weekly 5 wk; 4 h daily, 1 day weekly, 25 wk; 1 h daily, 4 days weekly, 25 wk 5 times weekly, 52 wk Rat Rat 4, 3, 2, times by 2 months and once Rat 1 injection Rat 4 h daily, 5 days weekly. 5 wk 4 Ii daily. 5 days weekly, 52 wk R.<( Rat SpragueDawlcy SpragucDawley Sprague* Dawley Sprague* Dawley SpragueDawley SpragueDawley II 420 420 340 120 15 13 160 160 320 80 15 13 ISO 150 300 60 15 21 80 70 150 75 - 15 1 day 13 45 44 89 240 240 iflO 43-46 120 10* Just started M altoni & Lefcminc: Carcinogenicity Bioassays GGC 003295 vO Annals New Y ork Academy of Sciences lAiJI.K l L'XPLUiMi.jsr HTI: Ktsm.TS Aftir 135 Weeks (F.np of the Experiment) Groups and Trc-iinu.nl Animals "A ith Tumors Aitim.il. - -- , -- ' - ' '---" Icy R.m) 1\ ink'll fil.tfi'1 catcitwmas* Tuts! ifftid So. pS*O hiKtny No. No. (wkj Aiii:it)>:irc<mias (trQf %Lif-itcy time No. LivrW AvrTARC lalrfUy lime Other SubcuUncous nn*in. mas Skin caret* (iv k ) (nk) Ilrain Olher Hfpa- ncuro* type tomas lilasto- aml/or fflat siu' Tout' I: VA, 2,500 ppm yfi 49 II: VC, 10,<XiO ppm 69 61 16 26 50 5 8 59 9 15 61 3' 4 3 i III: VC, 6,IXX) ppm 72 60 7 12 62 4 7 65 13 22 70 3- 3 1 i IV; VC, 2,500 ppm 74 59 2 3 33 6 It) 74 13 22 78 3* 3 12 V: VC, 500 ppm 67 59 4 7 79 4 7 83 7 12 81 2" I 13 VI: VC, 250 ppm 67 59 6 10 80 4 7 79 2* 4 VII: VC, 50 ppm 64 59 1 2 135 1 2 135 I 1 1 VIII: No treatment 68 58 7 7s 3 8' 5 4' 4" 39' 10- 38 31 32 22 16 10 6 Total 577 461 29 26 47 14 12 11 7 15 45 155 M alioni & Lcfcminc: Carcinogenicity Dioassays Alive animals after 20 weeks, when the first tumor (a Zymbal gland carcinoma) was observed. The percentages are referred to the corrected rummer. * Metastases to lung * Metastases to liver, lung, spleen, and brain. 4 Metastases to lung. * Several cases of breast fibroadenomas, adrenal and pituitary tumors (generally adenomas) have not been considered since their distribution in the dtHcrcni I'rouj)* dues not vary. ' t Several animals with 2 or more tumors. * One angiosarcoma of the bps-, l angiosarcoma of the nose; 1 intruabdominal angiosarcoma (nest to liver). * Two Zymbal gland adenomas; 3 mammary carcinomas: I neurilemmoma; I ovarian cystoadenocarcinoma * One angiosarcoma in subcutaneous librosing angioma; I ossifying parauricular angiosarcoma; I intraabdominal angiosarcoma (next to men. ' I iour Zymbal gland adenomas; I salivary gland adenocarcinoma: 2 hepatic and I peritoneal angiomas. intrtiibdomiiinl unvio^iircoivius [\ next to spleen and 1 next to ovary); J ossifying angiosarcoma of neck. One Zymbal gland ademmi.i; I mammary carcinoma; 2 ependymomas. " One pulmonary angiosarcoma; I angiosarcoma of uterus. * One mammary carcinoma; 2 lymphomas; I pulmonary (ibrosarcuma. One intraabdommal angiosarcoma (next to spleen); I inliailiorncic ossifying angiosarcoma. ()nc Zymbal gland adenoma; I mammary carcinoma; I lymphoma. * One intraahdommal diffused angiosarcoma. Three Zymbal gland adenomas; 2 mammary carcinomas; I subcutaneous angiopcricytoma; 3 uterine adenocarcinomas (I with sarcomatous componenty * One invasise acanthoma of Zymbal gland; I subcutaneous fibrosarcoma; 2 peritoneal libroangiomas; 2 uterine adenocarcinomas (I with sarcomatous component): I uterine leiomyosarcoma; I ovarian fibrosarcoma; I pulmonary rhabdoimosarcuma; 1 lymphoma. 00co^ nnals New York Academy of Sciences Experiment 15 was started as soon as we found 1 liver angiosarcoma, 1 extrahepatic angiosarcoma, and 1 nephroblastoma in 3 animals of the first ex periment, exposed to 50 ppm of VC for 1 year, and surviving 135 weeks from the beginning of the treatment. The animals are controlled weekly and weighed every 2 weeks during the period of treatment and monthly after the treatment is over. All the detectable gross pathological changes are recorded during the control. All the animals arc kept under observation until spontaneous death. The animals, when moribund, are isolated, in order to avoid cannibalism. A complete autopsy is made on each animal. Histological examinations are performed on Zymbal glands, interscapular brown fat, salivary glands, tongue, lungs, liver, kidneys, spleen, stomach, different segments of the intestine, bladder, brain, bones of the legs and feet, and any other organ with pathological lesions. All the animals exposed to the highest doses (30,000 and 10,000 ppm), with or without tumors, arc examined radiologically, during treatment and/or at death; moreover, radiological examinations are made on all animals bearing tumors, although exposed to the tower doses. Results The current results of several experiments are shown in the Tables 2-9. Some others are still not available. Tumors of different types may be present in the same animals. Zymbal gland carcinomas may be bilateral. Histologically they may repro duce, to some extent, the structure of the normal Zymbal gland (Figure 1). but often they present squamous, glandular, solid, anaplastic, and polymorphous patterns. Several of these different pictures may be observed in the same tumor. Metastascs of these tumors are sometimes found in the lung (Figure 2). Nephroblastomas are often bilateral. Their histological picture reminds us of an embryonal kidney (Figure 3k They metastasize to the liver, spleen, lung, and brain. Hyperplasia of nephroblastoma-like tissue is often observed in the kidney of treated rats, with or without nephroblastoma. Angiosarcomas and angiomas may be found at more than one site in the same animal. In liver they are often polvcentric. Hepatic and extrahcpatic angio sarcomas are more or less differentiated (Figures 4-9). They are morphologically Table 3 Experiment BTS: Results After 41 Weeks Aoimaf* fpracue- bawlry Rais) Animals with Tumors Groups and Tim linen c Tout Correeled no.* la) Sur vivors Zymbal (Jaod Carcinomas Angio sarcomas ! No.; % I Alavteenncryc 1li*m1e0 Nbelapshtroo mas Liver Ostitheesr Other antsydipt/eeor Total 1: VC. 30,000 ppm 60 60 48 12 i 20 35 i 12 Animals alive after 24 weeks, when the first tumor (a Zymbal gland carcinoma) was observed. The percentages arc referred to the jcprrected number.. Maltcmi & Lcfemine: Carcinogenicity Bioassays 203 Table 4 Experiment BT2: Results After 41 Weeks Groups and Treatment Animal*. t'-L'raeufDawl*y Rjits) Total Survivors Animals with Tumors Zymbal gland ncoamrcais Nephro blasto mas saArncogmioas Otythpeer aodor site 1: VC, 200 ppm 11: VC. 150 ppm III: VC, 100 ppm IV: No treatment Total 120 115 120 ioy 120 112 135 171 545 507 i* i * One subcutaneous ftbroangioma similar in rats, mice, and hamsters. Angiosarcomas frequently metastasize; as far as the liver angiosarcomas are concerned, the lung is the most frequent site of distant metastascs. Blood vessels ectasias, endothelial hyperplasia, associated or not associated with cellular atypia, are often observed in the liver and in other organs and tissues in treated animals, with or without local or distant angiosarcomas or angiomas. Therefore, the effect of VC on blood vessels and endothclia should be considered systematic. Angioblastic proliferation, angiomas, and angiosarcomas in the liver and in other sites may or may not be associated with fibroplasia. Front the histological observations, the sequence of local changes in the genesis of malignant vascular tumors appears to be as follows: endothelial hyperplasia, angiomas, atypias of endothelial cells in hyperplasia tdysplasiai and angiomas, angiosarcomas. Fibroangioblastic proliferation undergoing fibrosis is frequently observed in the spleen of the treated rats and mice. Skin carcinbmas in treated rats appear frequently to arise from sebaceous glands, of which they may reproduce in some extent the morphological charac ters (Figure 10k The hepatomas observed in treated rats are usually welt differentiated. Metastascs have been observed m the lung. Brain neuroblastomas arc very similar to the human medulloblastomas (Fig ure 11). Since they may be quite smalt and therefore not easily macroscoptcally detectable, wc arc now making serial sections of the brains of the treated rats, to obtain more precise information on their real incidence. The lung adenomas in treated mice are usually multiccmric: their number is higher in animals treated with heavier doses. 5)any of these tumors appear to undergo early malignant transformation. Mammary carcinomas may be solitary or multiple. They are usually well differentiated adenocarcinomas, with monomorphous or polymorphous arrange ment. The most distinct feature of these tumors is the frequency with which they present areas of squamous metaplasia (Figure 12). Up to the present no acroosteolytic lesion has been observed on our treated animals. Several of the tumors produced by VC are quite rare or exceptional. To our knowledge liver angiosarcomas, nephroblastomas, and neuroblastomas have 204 Annals New York Academy of Sciences jo xr eo -- --< h n f^i in * & %. O JvB -<N I I -- 6 o* -1 i i T able 5 E x p e r im e n t DT3: R esults A fter 66 W eeks' ra cm ^ li I o o <o -- r7 lIIlI i 222 -2C 57 111 - h* 2 -- .2 'o ~ Ea 'C vi nrtiNw .3.22 ^ J III Ih i -Ua c .o <3Ns C^4 i--r> io 5p^%, --< voo coc cooc Vu.i JVdi O ... |t 2 'I -- 5*5 S E c, - c =s= 5= 5 B JT -- S a ic^cai ^>>>^>5 -==>>> oU c-5c *- J7C J, --L? Cftj 1^3CC j c ft c. ^ | c*>gJr 3jr E E 1 C.^U(jO 2i JECOqO 0 H I 4 Maltoni & Lcfemine: Carcinoenicit) Bioassays 205 Table 6 Experiment BT7. Results After 41 Weeks Animals * (Wisiar Kata; Animal*. with Tumors* Croups end Treatment I: VC. 10.000 ppm II: VC, 6.000 ppm III: VC, 2.500 ppm IV: VC, 5U0 ppm V: VC, 250 ppm VI: VC, 50 ppm VII: No treatment Total Total ! ZymLial Suni- - aJand vors i1 nccamrua-* [ Anf'iosjn.nma1- Xrphru* blaste mas Liver Other sites 30 27 - (1) 30 26 - (U 30 23 -- (1) 30 27 . - (1) 30 26 t 30 28 : 1 40 38 ; 220 195 j -- <3) - 0) Other and>/ro*r ttie - in n i (i) Total - t2> - u> - (1) - (1) 1 1 (5) * In parentheses arc recorded the tumors found in male Sprague-Dawlc> rats of experiment BT1, after 41 weeks, t One angioma of the cecum. Table 7 Experiment BT5: Results After 75 Weeks Groups and Treatment Animals (Sprague* Daw ley Rats,) Total Survi vors Animals with Tumors Zvznbai v , klfCI- nomas -.tAoIbrWala"As* Angiosarcomas L*i'v" s!tihe*sr Oibrr type and/or Total site 1: VC, 10,000 ppm (breeders) II: VC, 6,000 ppm (breeders) 111: VC, 10,000 ppm (otisprings) IV: VC, 6,000 ppm (offsprings) Total 30 21 30 24 54 48 32 30 146 123 i* i it i 22 * Subcutaneous angiosarcoma on a 34.week-old male, t Subcutaneous angiosarcoma on a 22-wcek-old female. never been described as spontaneouslv occurring in rats. Liver and cxtrahepatic angiosarcomas have been induced only in a lew instances in experimental rodents (rats, hamsters, and mice) (for relerenees see Maltoni and L.cfeminc'i. As far as wc know this is the first time that nephroblastomas and neuroblastomas have been experimentally reproduced. CONCU.'StONS 1. Under our experimental conditions. VC produced tumors in the three animal species studied: rats, mice, and hamsters (as Jar as the last species is con cerned, the data should still be considered as preliminary). 206 Annals New York Academy of Sciences Experiment lilo: Results Aitir 25 Weeks Groups and Treatment AmmaU fGoldro Hamsters) Total Sun ivon AoLmals with Tumors Liver angio sarcomas Skin trichoepithet- lomas Lymph* oxnas Melan omas To La I: VC, 10,000 ppm II: VC, 6,000 ppm III: VC, 2,500 ppm IV: VC. 500 ppm V: VC, 250 ppm VI: VC, 50 ppm VII: No treatment Total 35 19 32 21 33 19 33 23 32 18 33 23 70 49 268 172 ii ii ii -t i i ii 23 i 4 * One animal with 3 tumors. t At the date (September 1974} on which the final draft of this report was s. mitted for publication, 1 liver angiosarcoma with pulmonary metasiases was obsen in this group. cf' T*ni.i H I.xi-ihiuini IlTi. Hisci.ts A lim 41 U'tiKi Ficurjc 1. Well differentiated Zymbat gland carcinoma i 207 H&E, X 190. 208 Annals New York Academy of Sciences Malioni & Lcfeminc: Carcinogenicity Bioassays 20' Figure 2. Pulmonary metastasis of well ditierentialed Zymbal gland carcinoma in rat. H&E. X 190. 2. The range of induced tumors varies to some extent from species to species. When given by inhalation VC produced: in rats. Zymbal gland carcinomas, neph roblastomas. angiosarcomas, and angiomas ot the liver and other sites, skin car cinomas. hepatomas, and brain neuroblastomas: in mice, lung adenomas (fre quently undergoing malignant transformation), mammary carcinomas, of a peculiar type, angiosarcomas and angiomas of the liver and of other sites, skin epithelial tumors: in hamsters, liver angiosarcomas and. as early evidence seems to suggest, skin trichoepitheliomas and lymphomas. Incidentally, liver angio sarcomas have been observed in all three animal species. 3. In the BT1 and BT4 experiments, VC shows a carcinogenic cflcct at 30 ppm. 4. From the BT1 experiment (the only one completed) a dose-response rela- - d - A. _ r,, . IS rt X '-jT'C'Tsi* t- ^Lv- V\ Figure 3. Nephroblastoma in rat. H&E, X 470. tionship clearly emerges, as far as angiosarcomas and nephroblastomas are co: corned, in the lower dose ranges: from 500 to 50 ppm for angiosarcomas ar. from 250 to 50 ppm for nephroblastomas. 5. A comparison of the results available at the present moment in rats c' posed for 12 and 4 months (BTl and BT3 experiments) shows that the ncoplas: response, as far as angiosarcomas and nephroblastomas arc concerned, is jllcctv by the length ot exposure to VC. 6. The comparison of the results obtained in rats of two different strains, i.t Sprague-Dawley (BTl) and Wistar (UT71, at the present moment, seems to su gest that the strain factor considerably alfects the neoplastic response. 7. The onset of two subcutaneous angiosarcomas in the offspring of breede: exposed durine pregnancy lor 7 days appears to indicate a transplacental edc. of VC. New York Academy of Sciences Makoni & Lefeminc: Carcinogenicity Bioussays 211 *9 m 9^ ,~z I - ** *CJK?* ^ 'l- T ,v ^ -4* -" * . C-.i..*' "v'- * ~ * * * -^->.r ' *' . _. . ; r 'l4 ** i # r_ -c:- ' ;^c r:/ J < *. V*-** * Figure 4. Liver angiosarcoma in rat. H&E, x 190. S. The observation of a tew ca'es of ossifying angiosarcomas suggests a new ntation in the pathoeenetic interpretation of acroosteolysis in workers ex:d to VC. The results presented in this report should be considered both preliminary and mplcte: preliminary since most of the experiments arc still in progress, and e at the initial stages: incomplete because a more profound and systematic -oscopical examination, which is now under way, of further serial histological ions, may disclose new initial, minute, undetected tumors. For the latter rcaprevious reports have been even more incomplete. The release of the prclimi- and incomplete results has been made necessary because of the importance 163200 390 of the topic, the pressure of the events and the requests. Since there have been more than 100.000 slides up to now. ] am sure that thO'C engaged in pathological screening of experimental material arc aware of our diflicult task. Our data have been periodically transmitted to the European Companies which have supported our research and are available to all interested parties. Before the end of 1972. a short time after it was known that VC was inducing in rats not onlv Zsmhal gland tumors, but also nephroblastomas and liver angio sarcomas. these results were also made known to the MCA (U.S.A.). This intor- maiion promoted clinical observations and cpidemtoloeieal inscsttgations. sshich in December 1973 led to the first discovers' of a liver angiosarcoma, as an oc cupational disease, in a worker of a U.S.A. factory producing VC-f'VC. 212 Annals New York Academy of Sciences Maltoni & Lcfcminc: Carcinogenicity Bio; 21 Figure 7. Liter aneiosarcoma in mouse associated with fibrosis. H&E. X 190. GGC 003292 A.nuii t urK Academy of Sciences Mahoni it Let'emine: Carcinogcniuit) Uiojssajs 215 f* ^ *J: * lri r.r I 13 S^aSSSSSS Figure 9. Kidney angiosarcoma in mouse. H&E, x 190. 216 nals New York Academy of Sciences Malloni & Lefeminc: Carcinogenicity Bioassays 217 Figure 10. Skin sebaceous, well diflcrcntiaiot), carcinoma in rat. H&E, X 190. Figure 11. Brain neuroblastoma with typical rosettes in rat. H&E. x J70. 218 Annals New Yt! catlemy of Sciences I | r arfsfs&ja*. - Figure 12. Mammary adenocarcinoma with squamous metaplasia in mouse. H&tE. X 190. May I recommend again that the VC carcinogenesis may serve as a convinc ing example for urgently promoting experimental bioassays for all new industrial compounds and for those compounds that are already widespread but whose effect we still ignore, to avoid occupational cancers. Our Institute is now undertaking projects of carcinogenicity bioussavs of other monomers employed in the plastic industry. References 1. Viola, P. L., A. Bloom &. A. Caputo. 1971. Oncogenic response of rat skin, lungs and bones to vinvl chloride. Cancer Res. 31:5 16-5 19. 2. MALTON!, C. & G. LErCMiNE. 1974. Ca rein ore ni city to bioassays of vinyl chloride. I. Research plan and early results. Environ. Res. 7: 387-405. INTERIM R RATS. H. \ M. L. Kepitn. Indus: A The following data are p. Bio-Test Laboratories, Inc. companies b; the Manuract. complete but because of the:and OSH A on April 15. 197a in this study w hich vs as v hamsters, and mice of both posed to cither 0, 2500, 200 week Mice will be exposed Rats and hamsters will be e* months The rats are COBS Char: hamsters are Golden Syrian, posure, water is present "0 Moribund and dead i:::r photographed. The major o: nation. Only the tissues from a shows the results to date ar cal comparisons can be rr.a. lected in the same way. On 1 NTERivt Summary or .Vo i>f tirout' Told Control r 50 ppm i 200 ppm t 2500 ppm ; 0 4 15 30 Prehmmarj findings : Laboratory, April. |y7J t Seven male and 2 l err.i had tumors in spleen, liv ;r. I Only mice with gross.;-