Exp. Path., Bd. 13, S. 44-51 (1977) Medical Academy of Erfurt, Institute of General Pathology and Pathological Anatomy (Director: Prof. Dr. sc. med. H. GUTHERT) Research Group Preventive Oncology (Head: Dozent Dr. sc, med. R. WARZOK)
Morphology of diethylnitrosamine-induced lung tumours in Dzungarian dwarf hamsters') By R. WARZOK and R. TRUST With 8 figures (Received September 10, 1976) Key-words: lung tumours, diethylnitrosamine, nitrosamines, transplacental tumour induction, hamster
Summary After transplacental application of 30 mgJkg b.w. diethylnitrosamine 16 out of 21 Dzungarian dwarf hamsters developed lung tumours. The histological picture of these tumours is described. The neoplasms are classified as papillary, tubular, or alveolar adenomas or adenocarcinomas, respectively. Different histological architectures occur in one and the same animal or even in different parts of the same tumour. The neoplasms derive from outgrowths of the epithelium of small bronchioles. The significance of the Dzungarian dwarf hamster as a suitable tool for transplacental and postnatal eancer research is discussed. The rapid increase in the frequency of lung cancer in man raises the question of etiological factors in the tumour development. During the last years, several agents have been identified by epidemiological and experimental studies. Nevertheless, the pathogenesis of tumours of the respiratory tract is still poorly understood. There seems to be little doubt that the vast majority of lung carcinogens are contaminants of the breathing air. However, under experimental conditions a number of chemical compounds, such as nitrosamines and carbamates may induce respiratory tract cancer in a large variety of mammalian species, regardless of the mode of application. The biological behaviour as well as the histological structure of animal tumours are of major importance for the solution of etiological and histo- genetical problems. Recently we succeeded in inducing lung tumours in Dzungarian dwarf hamsters after transplacental application of diethylnitrosamine (DENA). The morphology of these tumours will be described here.
Maieriol and ml!thods The experiments were carried out with animals of the eastern subspecies of the Dzungarian dwarf hamster (Phodopus sungorus campbelli) we received from the Institute of Experimental and Clinical Oncology, Moscow. The biology of this species has been described by POGOSIANZ and SOKOVA (1967). Randomly bred animals were housed in plastic or metallic cages and fed with millet-seeds as well as with several fruits and vegetables. Pregnant hamsters received one intraperitoneal injection of DENA (SchuchardtjMunich] in a concentration of 30 mg/kg b.w. (for details see THusT and WARZOK 1977). The offsprings were observed and animals in bad conditions were isolated and left to die spontaneously or were killed when moribund. At autopsy, all organs were inspected macroscopically. Tissue samples of the lung, trachea, liver, brain, kidney, spleen, and of all tumours were taken for histological examination. Paraffin embedded sections were stained with hematoxylin and eosin. If necessary, the following staining or impregnation methods were used: azan, PTAH, PAS, Goldner, Gomori. 1) Dedicated to the 65th birthday of Prof. Dr. sc. med. H. GUTHERT.
44
Results 15 litters yielded 29 animals 21 of which survived for more than 126 days, when the first tumour was registered. For date of carcinogen application, latency period, and frequency of tumours see TRUST and WARZOK (1977). Lung tumours were observed in 16 animals (76.2 per cent], Besides minute greyish nodules, large neoplasms that infiltrate extensive parts of the lungs can be observed. Two forms may be distinguished on the basis of gross distribution of the lesions - a more or less diffuse and a nodular variety, combination forms were observed, too. The diffuse form merges into the normal pulmonary tissue mimicking pneumonia. As a role the cut surface is soft and yellow-white and characteristically exsudes gelatinous or mucoid material in abundance. In the nodular form, the border between the tumour and the surrounding tissue is relatively sharp (fig. 1).
Fig. 1. Hamster No. 285, DENA 3 days a.p. Multiple lung tumours with sharp borders. HE, X 22
The histological examination reveals a variable picture comprising papillary, alveolar, and tubular structures. The papillary adenoma is the most common type of lung tumours. The papillary masses often present complex patterns of transverse and tangential sections of papillary arrangements (fig. 2). Occasionally the papillary masses disintegrate and undergo varying degrees of necrosis leaving cellular or amorphous debris with numerous inflammatory cells. As a role tumour cells are columnar with large ovoid basal nuclei. Sometimes they are extremely tall with apical vacuoles which mayor may not contain mucinous material. Mostly the mucin production is limited to some areas of the tumour. The mucus is situated either within the epithelial cells or in extracellular spaces. In some tumours, it is difficult to decide, whether the mucus secretion comes from the tumour cells or is merely retained by the tumour. Some neoplasms consist of cuboidal cells, either combined with cylindrocellular areas or as a uniform cuboidal cell proliferation. The cytoplasm is scanty and rarely contains mucus. Usually the growths are well differentiated and characterized by a uniform histological picture. Therefore, we classified them as papillary adenomas. In small tumours mitoses
45
Fig. 2. Hamster No. 275, DENA 1 day a.p. Highly differentiated papillary adenoma. HE, X 210.
Fig. 3. Hamster No. 283, DENA 3 days a.p. Alveolar adenoma with basally placed nuclei and large mucus containing vacuoles. HE, x 675.
46
Fig. 4. Hamst er No. 286, DENA 2 days a.p, Papillary ad enoma with numerous cilia. HE , X G75
Fig. 5. Hamst er No. 297, D E~A 6 hours a.p . Tubular adenocarcin oma with increased polym orphism and numerous mitoses. HE , x 675.
47
and polymorphous cells are rare, but in the larger ones, the number of mitotic figures increases, the polymorphism is more pronounced, and there is a more or less limited infiltration of the surrounding alveoli. These tumours are classified as papillary adenocarcinomas. In other tumours the characteristic cell type is a small columnar cell with a somewhat granular cytoplasm resembling epithelium of larger bronchi. The cytoplasm is more abundant, vacuolized, and more palely staining (fig. 3). These cells occur sometimes in a single layer but more frequently they are multilayered or may occur in solid masses. Mitotic figures are rare, but are relatively common in more atypical areas of larger tumours. Cilia may be present (fig. 4). As a rule these tumours produce mucus. In the mucus producing cells the nuclei are basally placed and the cytoplasm contains periodic acid-Schiff positive granules. The cells form tubules or gland-like structures in parts of the tumours (fig. 5). Often the lesions spred along the alveoli, so that the epithelium appears to be supported by the interalveolar septa forming alveolar structures (fig. 6). These neoplasms are regarded as benign (tu bular or alveolar adenomas). In larger growth the interalveolar septa are broken down as the proliferative process continues and the surrounding tissue is infiltrated. These changes are usually accompanied by a rise of atypical cells and polymorphism. We classified these tumours as tubular or alveolar adenocarcinomas. As in a half of the animals multiple lesions were found, beside large growths early stages of the tumour development and even premalignant changes could be registered. In small bronchioli atypical epithelium with irregular stratification and altered polarization was seen. The cells are enlarged with irregular nuclei and clumped chromatin (fig. 7). The amount of mucosubstances is increased. These changes were seen in many bronchioli of hamsters which had at the same time papillary adenomas or adenocarcinomas. Evidently, these elements form a transition to neoplastic proliferations. Small bronchiolar adenomas were found in a number of animals. They all appeared to derive from outgrowths of the epithelium of small bronchioles (fig. 8).
Fig. 6. Hamster No. 182, DENA 1 day a.p. Alveolar structures in a subpleurally localized adenoma. HE, x275.
48
Fig. 7. Hamster No. 297, DENA 6 hours a.p. Irregular polarization of the bronchiolar epithelium with clumped chromatin of the nuclei. HE, X 300.
• Fig. 8. Hamster No. 297, DENA 6 hours a.p. Papillary proliferation of bronchiolar epithelium. HE, x330. 4 Exp. Path. Bd. 13, H. 1
49
In one and the same hamster different histological tum our typ es occurred rather frequently. Even in a single lesion distinctive histological architectures were formed in different parts of the tumour. Therefore, it was impossible to present exact information concerning the frequency of one or th e other tumour ty pe. Metastases were seen neither in the lungs, including their lymphatic tissue, nor in ot her organs. Apart from tumours of t he respirat ory tra ct five animals developed neoplasms in other organs: adenomas of th e th yroid gland (1), of th e liver (1), and of th e breast (1) as well as one adenocarcinoma of th e prostate. In one hamster a cystoma of the ovary and a malignant lymphoma were found.
Discussion The Dzungarian dwarf hamster has been intr oduced into chemical carcinogenesis research by PLATONOVAand POGOSIANZ in 1969 and has proved to be a new suitable tool for cancer research and cytogenetic studies because of its comparatively few chromosomes (2n = 28), most of which can be recognized even in conventionally stained preparations (POGOSIANZ et al. 1970, SOKOVA and POGOSIANZ 1974, THUST 1974). So far, th e carcinogenic activity of 7,12-dimethylbenz[a]anthra cene, 3-meth ylcholanthrene, methylnitrosourea, urethan , dimethylnitrosamine, and diethylnitr osamine has been test ed in adult animals. After repeat ed injections of DENA into adult hamsters, VASILIEVA and SOKOVA (1971) found tumours in th e lungs and/or liver in 30 per cent. Co mpared with those experiments, after transplac ental application of DENA th e frequency of neoplasms is relatively high. Although distinct hist ological patt erns may be observed in different lesions, the described lung tum ours are evidently closely related. In various parts of t he tumours, gland-like struct ures with a tubular or alveolar pat tern and papillary formations may occur simultaneously. ,Ve are of th e opinion th at these histological struct ures represent different potencies of one and t he same epithelial cell and that t he t umours originate in t he bronchioles. The growths of th e Dzungarian dwarf hamster exhibit a similar histological picture like many spontaneous lung tumours of laboratory rodents, domestic animals, and tum ours induced by systemical or topical application of chemical carcinogens (KLARNER and GIESEKING 1960, DONTENWILL and ~IOHR 1961, 1962, DONTENWI LL et a!. 1961, HERROLD and DUNHAM1963, HERROLD 1964, THOMAS and SCH:\IAHL 1963, SAFFIOTTI et a!. 1968, GRUND:\IANN and STEINHOFF 1970, FERON 1972, STENBACK 1973, 1974, STENBACK et a!. 1973, ST UNZI et a!. 1974, BLAIR 1974, :NETTESHEIM and SCHREIBER 1975). However, a number of th ese aut hors described squamous cell metaplasias of t he tracheal, bronchial, bronchiolar, and even alveolar epith elium as well as keratinizing squamous components in adenomatous tumours. We have never observed th ese changes, neither within t he tumours nor in th e surrounding bronchial tr ee. In contrast to the Syrian golden hamster and to th e common European hamster which develop mainly neoplasms of th e upper respiratory tr act (DONTENWILL and MOHR 1961, DONTENWILL et al. 1961, MOHR et a!. 1972) we found only peripheral tumours. Evidently our findings correspond to those obtained after repeated subcutaneous injections of DENA into adult Dzungarian dwarf hamsters (VASILIEVA and SOKOVA 1971). It is still unknown whether DENA leads exclusively to peripheral adenomas and carcinomas in this species, since the site of origin of t he induced t umours varies not only from species to species, but in th e same species it appears dependent on such factors as dose level, schedule, and route of administration, survival rate and others ( :MONTESA ~O and SAFFIOTTI 19(8). More recently th is problem has been reviewed by HAA S et al. (1975). Further experiments are necessary to find out dose dependent differences in t he reaction of the Dzungarian dwarf hamster after tr ansplacental and postn atal application of DENA.
50
Literature BLAIR, W. H., Chemical induction of lung carcinomas in rats. In: Experimental lung cancer. Ed. by E. KARBE and J. F. PARK. Springer, Berlin-Heidelberg-New York 1974. DONTENWILL, W., und U. :.\IOHR, Carcinome des Respirationstraktes nach Behandlung von Goldhamstern mit Diathylnitrosamin. Z. Krebsforsch. 64, 305-312 (1961). - - Experimentelle Untersuchungen zum Problem der Karzinomentstehung im Respirationstrakt. II. Die Wirkung von Tabakrauchkondensaten und Zigarettenrauch auf die Lunge des Goldhamsters. Z. Krebsforsch. 6ii, 62-68 (1962). - - and ~I. ZAGEL, Uber die unterschiedliche Lungen-carcinogene Wirkung des Diathylnitrosamin bei Hamster und Ratte. Z. Krebsforsch. 64, 499-502 (1961). FERON, V. J., Respiratory tract tumors in hamsters after intratracheal instillations of benzo (a) pyrene alone and with furfural. Cancer Res. 32, 28-36 (1972). GRUND MANN, E., and D. STEINHOFF, Leber- und Lungentumoren nach 3,3'-Dichlor-4,4'-diaminodiphenylmethan bei Ratten. Z. Krebsforsch. 74, 28-39 (1970). HAAS, H., N. KMOCH and U. MOHR, Suseeptibility of gerbils (Meriones unguiculatus) to weekly subcutaneous and single intravenous injections of N-diethylnitrosamine. Z. Krebsforsch. 83, 233-238 (1975). HERROLD, K. M., Effect of the route of administration on the carcinogenic action of diethylnitrosamine. Brit. J. Cancer 18, 763-7G7 (1964). - and L. J. DUNHAM, Induction of tumors in the Syrian hamster with diethylnitrosamine (N-nitrosodiethylamine). Cancer Res. 23, 773-777 (1963). KLARNER, P., and R GIESEKIi'iG, Zur Ultrastruktur des Lungentumors der Maus, Z. Krebsforsch. 64, 7-21 (1960). MOHR, U., J. ALTHOFF and N. PAGE, Tumors of the respiratory system induced in the common European hamster by N-diethylnitrosamine. J. Natl, Cancer Inst. 49, 595-597 (1972). MONTESANO, R, and U. SAFFIOTTI, Carcinogenic response of the respiratory tract of Syrian golden hamsters to different doses of diethylnitrosamine. Cancer Res. 28, 2197-2210 (1968). NETTESHEIM, P., and H. SCHREIBER, Advances in experimental lung cancer research, In: Handbuch der allgemeinen Pathologie VI/7, III. Springer, Berlin-Heidelberg-New York 1975. PLATONOVA, G. M., and H. E. POGOSIANZ, The effect of thymidine on the occurrence of adenomas in mouse lung under the action of urethane and N-hydroxyurethnne (in Russian). Vop. Onkol. 15/5, 66-71 (1969). POGOSIANZ, H. E., and O. I. SOKOVA, Maintaining and breeding of the Djungarian hamster under laboratory conditions. Z. Versuchstierk. 9, 292-297 (1967). - - and 1. I. lVANOVICH, The normal karyotype of the Djungarian hamster. Tsitologia (Leningrad) 12, 1297-1306 (1970). SAFFIOTTI, U., F. CEFIC and L. H. KOLB, A method for the experimental induction of bronchiogenic carcinoma. Cancer Res. 28, 104-124 (1968). SOKOVA, O. I., and H. E. POGOSIANZ, The karyotype of the Djungarian hamster after different staining of chromosomes. Tsitologia (Leningrad) 10, 1303-1305 (1974). STEi'iBACK, F., Morphologic characteristics of experimentally induced lung tumors and their precursors in hamsters. Acta cytol. 17, 47G-486 (1973). - Morphogenesis of experimental lung cancer in hams' ers. The effect of carrier dust. In: Experimental lung cancer. Ed. by E. KARBE and F. J. PARK. Springer, Berlin-Heidelberg-New York 1974. - A. FERRERO and P. SHUBIK, Synergistic effect of diethylnitrosarnine and different dusts on respiratory carcinogenesis in hamsters. Cancer Res. 33, 2209-2214 (1973). STUNZI, H., K. W. HEAD and S. W. NIELSEN, I. Tumours of the lung. Bull. WId. Hlth. Org. 50, 9-19 (1974). THOMAS, C., and D. SCHMAHL, Zur Morphologie der durch intravenose Injektion von Nitrosomethylurethan erzeugten Lungentumoren bei der Ratte. Z. Krebsforsch. 65, 294-302 (1963). THUST, R, G-banding and late replication of the Djungarian dwarf hamster chromosomes. Exp. Path. 9, 153-15G (1974). - and R WARZOK, Transplazentare karzinogene Wirkung von Diathylnitrosamin beim Dsungarischen Hamster. Zbl. allg. Path. (1977), in press). VASILIEVA, N. N., and O. I. SOKOVA, On the blastomogenic action of nitrosamines (DMNA, DENA, MNU) on Djungarian hamsters (in Russian). Vop, Onkol. 17/4, 58-63 (1971). Authors' addresses: Dozent Dr. sc. med. R WARZOK and Dr. sc. nat. R THUST, Medical Academy of Erfurt, Institute of Pathology, Research Group Preventive Oncology, DDR-50 Erfurt, Nordhauser StraBe 74.
4*
51
Morphology of diethylnitrosamine-induced lung tumours in Dzungarian dwarf hamsters') By R. WARZOK and R. TRUST With 8 figures (Received September 10, 1976) Key-words: lung tumours, diethylnitrosamine, nitrosamines, transplacental tumour induction, hamster
Summary After transplacental application of 30 mgJkg b.w. diethylnitrosamine 16 out of 21 Dzungarian dwarf hamsters developed lung tumours. The histological picture of these tumours is described. The neoplasms are classified as papillary, tubular, or alveolar adenomas or adenocarcinomas, respectively. Different histological architectures occur in one and the same animal or even in different parts of the same tumour. The neoplasms derive from outgrowths of the epithelium of small bronchioles. The significance of the Dzungarian dwarf hamster as a suitable tool for transplacental and postnatal eancer research is discussed. The rapid increase in the frequency of lung cancer in man raises the question of etiological factors in the tumour development. During the last years, several agents have been identified by epidemiological and experimental studies. Nevertheless, the pathogenesis of tumours of the respiratory tract is still poorly understood. There seems to be little doubt that the vast majority of lung carcinogens are contaminants of the breathing air. However, under experimental conditions a number of chemical compounds, such as nitrosamines and carbamates may induce respiratory tract cancer in a large variety of mammalian species, regardless of the mode of application. The biological behaviour as well as the histological structure of animal tumours are of major importance for the solution of etiological and histo- genetical problems. Recently we succeeded in inducing lung tumours in Dzungarian dwarf hamsters after transplacental application of diethylnitrosamine (DENA). The morphology of these tumours will be described here.
Maieriol and ml!thods The experiments were carried out with animals of the eastern subspecies of the Dzungarian dwarf hamster (Phodopus sungorus campbelli) we received from the Institute of Experimental and Clinical Oncology, Moscow. The biology of this species has been described by POGOSIANZ and SOKOVA (1967). Randomly bred animals were housed in plastic or metallic cages and fed with millet-seeds as well as with several fruits and vegetables. Pregnant hamsters received one intraperitoneal injection of DENA (SchuchardtjMunich] in a concentration of 30 mg/kg b.w. (for details see THusT and WARZOK 1977). The offsprings were observed and animals in bad conditions were isolated and left to die spontaneously or were killed when moribund. At autopsy, all organs were inspected macroscopically. Tissue samples of the lung, trachea, liver, brain, kidney, spleen, and of all tumours were taken for histological examination. Paraffin embedded sections were stained with hematoxylin and eosin. If necessary, the following staining or impregnation methods were used: azan, PTAH, PAS, Goldner, Gomori. 1) Dedicated to the 65th birthday of Prof. Dr. sc. med. H. GUTHERT.
44
Results 15 litters yielded 29 animals 21 of which survived for more than 126 days, when the first tumour was registered. For date of carcinogen application, latency period, and frequency of tumours see TRUST and WARZOK (1977). Lung tumours were observed in 16 animals (76.2 per cent], Besides minute greyish nodules, large neoplasms that infiltrate extensive parts of the lungs can be observed. Two forms may be distinguished on the basis of gross distribution of the lesions - a more or less diffuse and a nodular variety, combination forms were observed, too. The diffuse form merges into the normal pulmonary tissue mimicking pneumonia. As a role the cut surface is soft and yellow-white and characteristically exsudes gelatinous or mucoid material in abundance. In the nodular form, the border between the tumour and the surrounding tissue is relatively sharp (fig. 1).
Fig. 1. Hamster No. 285, DENA 3 days a.p. Multiple lung tumours with sharp borders. HE, X 22
The histological examination reveals a variable picture comprising papillary, alveolar, and tubular structures. The papillary adenoma is the most common type of lung tumours. The papillary masses often present complex patterns of transverse and tangential sections of papillary arrangements (fig. 2). Occasionally the papillary masses disintegrate and undergo varying degrees of necrosis leaving cellular or amorphous debris with numerous inflammatory cells. As a role tumour cells are columnar with large ovoid basal nuclei. Sometimes they are extremely tall with apical vacuoles which mayor may not contain mucinous material. Mostly the mucin production is limited to some areas of the tumour. The mucus is situated either within the epithelial cells or in extracellular spaces. In some tumours, it is difficult to decide, whether the mucus secretion comes from the tumour cells or is merely retained by the tumour. Some neoplasms consist of cuboidal cells, either combined with cylindrocellular areas or as a uniform cuboidal cell proliferation. The cytoplasm is scanty and rarely contains mucus. Usually the growths are well differentiated and characterized by a uniform histological picture. Therefore, we classified them as papillary adenomas. In small tumours mitoses
45
Fig. 2. Hamster No. 275, DENA 1 day a.p. Highly differentiated papillary adenoma. HE, X 210.
Fig. 3. Hamster No. 283, DENA 3 days a.p. Alveolar adenoma with basally placed nuclei and large mucus containing vacuoles. HE, x 675.
46
Fig. 4. Hamst er No. 286, DENA 2 days a.p, Papillary ad enoma with numerous cilia. HE , X G75
Fig. 5. Hamst er No. 297, D E~A 6 hours a.p . Tubular adenocarcin oma with increased polym orphism and numerous mitoses. HE , x 675.
47
and polymorphous cells are rare, but in the larger ones, the number of mitotic figures increases, the polymorphism is more pronounced, and there is a more or less limited infiltration of the surrounding alveoli. These tumours are classified as papillary adenocarcinomas. In other tumours the characteristic cell type is a small columnar cell with a somewhat granular cytoplasm resembling epithelium of larger bronchi. The cytoplasm is more abundant, vacuolized, and more palely staining (fig. 3). These cells occur sometimes in a single layer but more frequently they are multilayered or may occur in solid masses. Mitotic figures are rare, but are relatively common in more atypical areas of larger tumours. Cilia may be present (fig. 4). As a rule these tumours produce mucus. In the mucus producing cells the nuclei are basally placed and the cytoplasm contains periodic acid-Schiff positive granules. The cells form tubules or gland-like structures in parts of the tumours (fig. 5). Often the lesions spred along the alveoli, so that the epithelium appears to be supported by the interalveolar septa forming alveolar structures (fig. 6). These neoplasms are regarded as benign (tu bular or alveolar adenomas). In larger growth the interalveolar septa are broken down as the proliferative process continues and the surrounding tissue is infiltrated. These changes are usually accompanied by a rise of atypical cells and polymorphism. We classified these tumours as tubular or alveolar adenocarcinomas. As in a half of the animals multiple lesions were found, beside large growths early stages of the tumour development and even premalignant changes could be registered. In small bronchioli atypical epithelium with irregular stratification and altered polarization was seen. The cells are enlarged with irregular nuclei and clumped chromatin (fig. 7). The amount of mucosubstances is increased. These changes were seen in many bronchioli of hamsters which had at the same time papillary adenomas or adenocarcinomas. Evidently, these elements form a transition to neoplastic proliferations. Small bronchiolar adenomas were found in a number of animals. They all appeared to derive from outgrowths of the epithelium of small bronchioles (fig. 8).
Fig. 6. Hamster No. 182, DENA 1 day a.p. Alveolar structures in a subpleurally localized adenoma. HE, x275.
48
Fig. 7. Hamster No. 297, DENA 6 hours a.p. Irregular polarization of the bronchiolar epithelium with clumped chromatin of the nuclei. HE, X 300.
• Fig. 8. Hamster No. 297, DENA 6 hours a.p. Papillary proliferation of bronchiolar epithelium. HE, x330. 4 Exp. Path. Bd. 13, H. 1
49
In one and the same hamster different histological tum our typ es occurred rather frequently. Even in a single lesion distinctive histological architectures were formed in different parts of the tumour. Therefore, it was impossible to present exact information concerning the frequency of one or th e other tumour ty pe. Metastases were seen neither in the lungs, including their lymphatic tissue, nor in ot her organs. Apart from tumours of t he respirat ory tra ct five animals developed neoplasms in other organs: adenomas of th e th yroid gland (1), of th e liver (1), and of th e breast (1) as well as one adenocarcinoma of th e prostate. In one hamster a cystoma of the ovary and a malignant lymphoma were found.
Discussion The Dzungarian dwarf hamster has been intr oduced into chemical carcinogenesis research by PLATONOVAand POGOSIANZ in 1969 and has proved to be a new suitable tool for cancer research and cytogenetic studies because of its comparatively few chromosomes (2n = 28), most of which can be recognized even in conventionally stained preparations (POGOSIANZ et al. 1970, SOKOVA and POGOSIANZ 1974, THUST 1974). So far, th e carcinogenic activity of 7,12-dimethylbenz[a]anthra cene, 3-meth ylcholanthrene, methylnitrosourea, urethan , dimethylnitrosamine, and diethylnitr osamine has been test ed in adult animals. After repeat ed injections of DENA into adult hamsters, VASILIEVA and SOKOVA (1971) found tumours in th e lungs and/or liver in 30 per cent. Co mpared with those experiments, after transplac ental application of DENA th e frequency of neoplasms is relatively high. Although distinct hist ological patt erns may be observed in different lesions, the described lung tum ours are evidently closely related. In various parts of t he tumours, gland-like struct ures with a tubular or alveolar pat tern and papillary formations may occur simultaneously. ,Ve are of th e opinion th at these histological struct ures represent different potencies of one and t he same epithelial cell and that t he t umours originate in t he bronchioles. The growths of th e Dzungarian dwarf hamster exhibit a similar histological picture like many spontaneous lung tumours of laboratory rodents, domestic animals, and tum ours induced by systemical or topical application of chemical carcinogens (KLARNER and GIESEKING 1960, DONTENWILL and ~IOHR 1961, 1962, DONTENWI LL et a!. 1961, HERROLD and DUNHAM1963, HERROLD 1964, THOMAS and SCH:\IAHL 1963, SAFFIOTTI et a!. 1968, GRUND:\IANN and STEINHOFF 1970, FERON 1972, STENBACK 1973, 1974, STENBACK et a!. 1973, ST UNZI et a!. 1974, BLAIR 1974, :NETTESHEIM and SCHREIBER 1975). However, a number of th ese aut hors described squamous cell metaplasias of t he tracheal, bronchial, bronchiolar, and even alveolar epith elium as well as keratinizing squamous components in adenomatous tumours. We have never observed th ese changes, neither within t he tumours nor in th e surrounding bronchial tr ee. In contrast to the Syrian golden hamster and to th e common European hamster which develop mainly neoplasms of th e upper respiratory tr act (DONTENWILL and MOHR 1961, DONTENWILL et al. 1961, MOHR et a!. 1972) we found only peripheral tumours. Evidently our findings correspond to those obtained after repeated subcutaneous injections of DENA into adult Dzungarian dwarf hamsters (VASILIEVA and SOKOVA 1971). It is still unknown whether DENA leads exclusively to peripheral adenomas and carcinomas in this species, since the site of origin of t he induced t umours varies not only from species to species, but in th e same species it appears dependent on such factors as dose level, schedule, and route of administration, survival rate and others ( :MONTESA ~O and SAFFIOTTI 19(8). More recently th is problem has been reviewed by HAA S et al. (1975). Further experiments are necessary to find out dose dependent differences in t he reaction of the Dzungarian dwarf hamster after tr ansplacental and postn atal application of DENA.
50
Literature BLAIR, W. H., Chemical induction of lung carcinomas in rats. In: Experimental lung cancer. Ed. by E. KARBE and J. F. PARK. Springer, Berlin-Heidelberg-New York 1974. DONTENWILL, W., und U. :.\IOHR, Carcinome des Respirationstraktes nach Behandlung von Goldhamstern mit Diathylnitrosamin. Z. Krebsforsch. 64, 305-312 (1961). - - Experimentelle Untersuchungen zum Problem der Karzinomentstehung im Respirationstrakt. II. Die Wirkung von Tabakrauchkondensaten und Zigarettenrauch auf die Lunge des Goldhamsters. Z. Krebsforsch. 6ii, 62-68 (1962). - - and ~I. ZAGEL, Uber die unterschiedliche Lungen-carcinogene Wirkung des Diathylnitrosamin bei Hamster und Ratte. Z. Krebsforsch. 64, 499-502 (1961). FERON, V. J., Respiratory tract tumors in hamsters after intratracheal instillations of benzo (a) pyrene alone and with furfural. Cancer Res. 32, 28-36 (1972). GRUND MANN, E., and D. STEINHOFF, Leber- und Lungentumoren nach 3,3'-Dichlor-4,4'-diaminodiphenylmethan bei Ratten. Z. Krebsforsch. 74, 28-39 (1970). HAAS, H., N. KMOCH and U. MOHR, Suseeptibility of gerbils (Meriones unguiculatus) to weekly subcutaneous and single intravenous injections of N-diethylnitrosamine. Z. Krebsforsch. 83, 233-238 (1975). HERROLD, K. M., Effect of the route of administration on the carcinogenic action of diethylnitrosamine. Brit. J. Cancer 18, 763-7G7 (1964). - and L. J. DUNHAM, Induction of tumors in the Syrian hamster with diethylnitrosamine (N-nitrosodiethylamine). Cancer Res. 23, 773-777 (1963). KLARNER, P., and R GIESEKIi'iG, Zur Ultrastruktur des Lungentumors der Maus, Z. Krebsforsch. 64, 7-21 (1960). MOHR, U., J. ALTHOFF and N. PAGE, Tumors of the respiratory system induced in the common European hamster by N-diethylnitrosamine. J. Natl, Cancer Inst. 49, 595-597 (1972). MONTESANO, R, and U. SAFFIOTTI, Carcinogenic response of the respiratory tract of Syrian golden hamsters to different doses of diethylnitrosamine. Cancer Res. 28, 2197-2210 (1968). NETTESHEIM, P., and H. SCHREIBER, Advances in experimental lung cancer research, In: Handbuch der allgemeinen Pathologie VI/7, III. Springer, Berlin-Heidelberg-New York 1975. PLATONOVA, G. M., and H. E. POGOSIANZ, The effect of thymidine on the occurrence of adenomas in mouse lung under the action of urethane and N-hydroxyurethnne (in Russian). Vop. Onkol. 15/5, 66-71 (1969). POGOSIANZ, H. E., and O. I. SOKOVA, Maintaining and breeding of the Djungarian hamster under laboratory conditions. Z. Versuchstierk. 9, 292-297 (1967). - - and 1. I. lVANOVICH, The normal karyotype of the Djungarian hamster. Tsitologia (Leningrad) 12, 1297-1306 (1970). SAFFIOTTI, U., F. CEFIC and L. H. KOLB, A method for the experimental induction of bronchiogenic carcinoma. Cancer Res. 28, 104-124 (1968). SOKOVA, O. I., and H. E. POGOSIANZ, The karyotype of the Djungarian hamster after different staining of chromosomes. Tsitologia (Leningrad) 10, 1303-1305 (1974). STEi'iBACK, F., Morphologic characteristics of experimentally induced lung tumors and their precursors in hamsters. Acta cytol. 17, 47G-486 (1973). - Morphogenesis of experimental lung cancer in hams' ers. The effect of carrier dust. In: Experimental lung cancer. Ed. by E. KARBE and F. J. PARK. Springer, Berlin-Heidelberg-New York 1974. - A. FERRERO and P. SHUBIK, Synergistic effect of diethylnitrosarnine and different dusts on respiratory carcinogenesis in hamsters. Cancer Res. 33, 2209-2214 (1973). STUNZI, H., K. W. HEAD and S. W. NIELSEN, I. Tumours of the lung. Bull. WId. Hlth. Org. 50, 9-19 (1974). THOMAS, C., and D. SCHMAHL, Zur Morphologie der durch intravenose Injektion von Nitrosomethylurethan erzeugten Lungentumoren bei der Ratte. Z. Krebsforsch. 65, 294-302 (1963). THUST, R, G-banding and late replication of the Djungarian dwarf hamster chromosomes. Exp. Path. 9, 153-15G (1974). - and R WARZOK, Transplazentare karzinogene Wirkung von Diathylnitrosamin beim Dsungarischen Hamster. Zbl. allg. Path. (1977), in press). VASILIEVA, N. N., and O. I. SOKOVA, On the blastomogenic action of nitrosamines (DMNA, DENA, MNU) on Djungarian hamsters (in Russian). Vop, Onkol. 17/4, 58-63 (1971). Authors' addresses: Dozent Dr. sc. med. R WARZOK and Dr. sc. nat. R THUST, Medical Academy of Erfurt, Institute of Pathology, Research Group Preventive Oncology, DDR-50 Erfurt, Nordhauser StraBe 74.
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