Skin lesions in patients treated with imatinib mesylate: a 5-year prospective study

Imatinib mesylate (IM) represents the first-line treatment of patients with chronic myeloid leukemia (CLM) or gastrointestinal stromal tumor (GIST). It presents several side effects. However, less than 10% are nonhematologic including nausea, vomiting, diarrhea, muscle cramps, and cutaneous reactions. The aim of our study was to identify data regarding IM cutaneous adverse effects (AEs) to improve the clinical diagnosis and management of the more frequent side effects. Skin examination should be done before and during IM treatment so that AEs can be diagnosed and treated early with less impact on chemotherapy treatments and on the quality of life of the patient.

Multiple eruptive dermatofibromas in a patient with dermatomyositis taking prednisolone and methotrexate

Dermatofibroma (DF) is a common, benign, dermal tumor, often occurring as a single lesion. Multiple eruptive DFs are rare and usually associated with autoimmune diseases, immunosuppressant therapy, or both. We present the case of a 28-year-old woman with dermatomyositis who developed multiple eruptive DFs after undergoing methotrexate and corticosteroid treatment. Immunosuppressants such as methotrexate and corticosteroids might cause multiple eruptive DFs.

[Antitumor cross-resistance of trichinosis]

Our experiments were concerned with formation of antitumor cross-resistance by Trichinella spiralis infection in rats. Prophylactic infection was followed by an insignificant decrease in the number of 3,4-benzpyrene-induced malignant fibrous histiocytoma. It also inhibited mammary gland cancer induced by 7,12-dimethylbenzo(a)anthracene. No significant influence on the formation of fibroadenomas as a side effect was reported.

Multiple eruptive dermatofibromas in patients with systemic lupus erythematosus treated with prednisone

Solitary dermatofibromas are a common occurrence, especially on the lower limbs of young women, while multiple dermatofibromas (MDF) are rare, accounting for less than 0.3% of all dermatofibromas and may suddenly develop in immunosuppressed patients. We report a patient with systemic lupus erythematosus (SLE) who developed MDF while she was taking oral prednisone. A 46-year-old woman presented in 1989 complaining of photosensitivity, arthralgias, fatigue, malaise and dyspepsia. The patient denied fever, Raynaud's phenomenon, oral ulcer and hair loss. On examination she presented a typical SLE malar rash. Erythrocyte sedimentation rate (ESR) was elevated (54 mm/h). Speckle patterned IgG/IgM antinuclear antibodies were present at 1/1280 titer. Antibodies anti Ro/SSA were detected by counterimmunelectrophoresis up to 1/8 titer. Other laboratory findings were negative or within normal limits. Systemic lupus erythematosus was diagnosed and the patient given 50 mg/day prednisone. After a few months, both clinical symptoms and immunologic parameters improved. Eighteen months later, prednisone was replaced by 500 mg/day hydroxychloroquine. In 1994, she presented again with malar rash, arthralgias and facial hyperpigmentation. Prednisone 15 mg/day was reintroduced and hydroxychloroquine stopped being a possible cause of the facial hyperpigmented macules. In 1996, while she was taking 5 mg/day prednisone, several nodules developed on her limbs within a few months. On examination we observed 16 firm, slightly elevated 3-15-mm wide brown nodules on her arms, legs and trunk. A biopsy specimen of a lesion of the trunk revealed an epidermal seborrheic-keratosis-like hyperplasia with dermal fibrosis and fibroblastic proliferation (Fig. 1). Dermatofibroma was diagnosed.

Reactive oxygen-induced carcinogenesis causes hypermethylation of p16(Ink4a) and activation of MAP kinase

BACKGROUND

Implantation of foreign materials into mice and humans has been noted to result in the appearance of soft tissue sarcomas at the site of implantation. These materials include metal replacement joints and Dacron vascular grafts. In addition, occupational exposure to nickel has been shown to result in an increased risk of carcinogenesis. The molecular mechanisms of foreign body-induced carcinogenesis are not fully understood.

MATERIALS AND METHODS

In order to gain insight into these mechanisms, we implanted nickel sulfide into wild type C57BL/6 mice as well as a mouse heterozygous for the tumor suppressor gene, p53. Malignant fibrous histiocytomas arose in all mice, and we have characterized the profile of tumor suppressor genes and signal transduction pathways altered in these cells.

RESULTS

All tumors demonstrated hypermethylation of the tumor suppressor gene p16, as well as activation of the mitogen activated protein kinase (MAP kinase) signaling pathway. This knowledge may be beneficial in the prevention and treatment of tumors caused by foreign body implantation.

CONCLUSIONS

Oxidative stress induced by nickel sulfide appears to cause loss of p16 and activation of MAP kinase signaling. These findings support the hypothesis of synergistic interactions between MAP kinase activation and p16 loss in carcinogenesis.

Metamorphosed fibroblasts and their relation to the histogenesis of malignant fibrous histiocytoma in experimental murine model

Malignant fibrous histiocytoma (MFH) is a clinicopathologically established entity, but its histogenesis remains to be clarified. We have reported the existence of a specific cell type, the "fibrohistiocytoid (FH) cells", in various chronic inflammatory tissues. The FH cells are the metamorphosed fibroblasts and we have revealed the morphological resemblance between FH cells and MFH cells. In the present study we carried out some experiments to ascertain whether the FH cells have a possibility of neoplastic potential for the development of MFH in mice. A total of 50 female Balb/c mice treated with a chemical carcinogen, 9,10 dimethyl-1,2-benzanthracene (DMBA), were examined histopathologically from 8 to 22 weeks after the initial treatment. It was found that 1) the chemically induced tumors in the mice resembled human pleomorphic/ storiform variant of MFH and cells from the tumor were transplantable subcutaneously in the back of another mouse, 2) the tumors were composed mainly of malignant FH cells, and there were many benign FH cells and fibroblasts in granulation tissues obtained at the initial stage of the experiment, 3) all DNA histograms obtained from MFHs were aneuploid and granulation tissues were diploid, and 4) benign FH cells in the granulation tissue appeared to have higher DNA synthesis activity than typical fibroblasts on the basis of bromodeoxyuridine (BrdU) labeling and cytofluorometric studies. From these findings, we suggest that the FH cells are not only a merely morphologically changed fibroblast, but also a biologically ominous cell which may contribute to develop MFH in mice.

Morphological characterization of spindle cell tumors induced in transgenic Tg.AC mouse skin

Transgenic Tg.AC mice carry a v-Ha-ras coding region flanked by a zeta-globin promoter and an SV40 polyadenylation signal sequence. These mice respond to carcinogens by developing epidermal papillomas. In some cases, malignancies develop at the sites of these papillomas. Various patterns of squamous cell differentiation were observed in these malignancies. One malignancy that developed at the site of the papillomas was composed of bundles of spindle cells. This lesion is difficult to distinguish from fibrosarcomas by light microscopy. We characterized 16 of these malignancies (tentatively classified as spindle cell tumors) to determine if they were of epithelial or mesenchymal origin. Papillomas were induced in Tg.AC mice by full thickness wounding, 12-O-tetradecanoyl-13-phorbol acetate treatment, or ultraviolet radiation. With time, some papillomas became broad-based, downwardly invading lesions. These lesions were examined by light microscopy with immunohistochemical analysis for cytokeratins and by electron microscopy. Immunohistochemical examination with a polyclonal anti-cytokeratin antibody demonstrated various degrees of keratin staining in all tumors examined. Attenuated desmosomes were also observed in these lesions by electron microscopy. These results indicate an epithelial origin for these malignancies; therefore, they should be classified as spindle cell carcinomas.

In vivo tumouricidal effect of T lymphocytes activated by liposomes containing adriamycin on chemically-induced rat malignant fibrous histiocytoma

The augmentative effect of liposomes containing adriamycin (LADM) in the host-tumour immune mechanism was assessed using 9,10-dimethyl-1,2-benzanthracene induced rat malignant fibrous histiocytoma (MFH). The antitumour effect of LADM was analyzed using a double grafted tumour system in which F344 rats first received simultaneous s.c. inoculations of MFH cells in both right and left flanks and were then injected with 0.2 mg of LADM into the right tumour on Day 10, 12, and 14. The growth of a remote, non-treated tumour was strongly inhibited, and the infiltration of CD8+ or CD4+ cells at the tumour periphery was histologically revealed. This inhibition was not observed in F344 nu/nu athymic rats. Winn neutralizing assay with T cell-rich splenic lymphocytes from each drug-treated MFH-bearing rat showed that complete regression of the tumour at a low effector/target ratio occurred only in the LADM-treated group. Furthermore, the tumouricidal effects were demonstrated in coexistence with CD8+ cells and CD4+ cells by assay with FACS sorting splenic lymphocytes. These results strongly suggest that intratumoural administration of LADM caused the systemic augmentation of the MFH-bearing host immune mechanism, and that the augmented response after LADM treatment was induced by the cytotoxic CD8+ lymphocytes dependent on the CD4+ lymphocytes.

Lack of an antitumoral effect of immunomodulatory galactoside-specific mistletoe lectin on N-methyl-N-nitrosourea-induced urinary bladder carcinogenesis in rats

The aim of the present animal experiment was to study the effect of galactoside-specific lectin or agglutinin (VAA) from mistletoe (Viscum album L.) on chemically induced tumor development in the urinary bladder of rats. Since VAA has been shown to exert a remarkable immunomodulating effect, any change in tumor formation would indicate a lectin-triggered immune control of urothelial carcinogenesis in the used model. To produce vesical neoplasms the direct-acting urothelial carcinogen N-methyl-N-nitrosourea (MNU) was administered at a single intravesical dose (7.5 mg/kg body weight). Highly purified VAA was given subcutaneously twice a week at the immunomodulatory dose of 1 ng/kg body weight over a period of 6 months during the critical phases of tumor development. After a total experimental time of 15 months the incidence of epithelial bladder tumors was 29.3% in controls versus 27.9% in rats additionally receiving the lectin and thus not significantly different in both experimental groups. There were, moreover, no substantial differences in the histopathologic spectrum of epithelial tumors induced, their patterns of growth, grades of cellular malignancy and local extension. The frequency and histopathology of mesenchymal bladder tumors as well as the incidence and morphology of carcinomas of the ureters and renal pelves also proved to be similar in controls and in rats treated with VAA. In conclusion, the present data provide no evidence for a modifying or even inhibitory effect of the immunomodulatory galactoside-specific mistletoe lectin on experimental urothelial carcinogenesis.

Differential diagnosis of malignant tumours in the abdominal cavity of rats after intraperitoneal injection of crocidolite or benzo[a]pyrene

In our investigation (i.p. test), crocidolite and benzo[a]pyrene, both caused a progression from initially reactive, then autonomously transformed proliferation of myofibroblasts and undifferentiated mesenchymal cells to malignant, multidirectionally differentiated (desmin and ED-1 positive) fibro-histiocytic tumours. Immunohistochemically these tumours showed no morphological characteristics (for example co-expression of vimentin and keratin in spindle-shaped tumour cells) of human asbestos-associated malignant mesotheliomas. On the other hand many tumour cells induced by crocidolite and benzo[a]pyrene had an ultrastructural appearance resembling fibroblasts and myofibroblasts. These have been demonstrated in only a few desmoplastic and sarcomatous mesotheliomas in human beings. None of the tumours revealed the typical ultrastructural features of epitheloid or transitional mesotheliomas. Apparently, both carcinogenic substances induce the transformation of undifferentiated pluripotent mesenchymal cells in rat peritoneum, regardless of their localization in the submesothelial compartment or perivascular connective tissue (preferentially after crocidolite application) or in the connective tissue pseudocapsule of major benzo[a]pyrene containing beeswax/tricaprylin depots in the mesometrium and mesenterial fatty tissue. In this way asbestos fibres in this animal experiment do not seem to induce an arrest in differentiation of intermediate or immature mesothelial cells as supposed formerly, but rather affect undifferentiated mesenchyme cells and myofibroblasts. This is an explanation for the immunohistochemical expression of markers of muscular differentiation in these tumour cells, which is known to occur in human malignant fibro-histiocytic tumours. If supplementary immunohistochemical investigations with different keratin antibodies also fail to confirm the mesothelial differentiation of the tumours induced in our i.p. test, the decision to call them "mesotheliomas" should be reconsidered. Further immuno-transmission-electron microscopical investigations with intermediate filament or macrophage antibodies are needed to clarify whether the term malignant "fibrohistiocytic sarcoma", "mesenchymoma" or "mesothelioblastoma" would be more correct from the morphological point of view.

Carcinogenicity of nitropyrenes in the newborn female rat

The carcinogenicities of 1-nitropyrene (1-NP), 4-nitropyrene (4-NP), 1,3-dinitropyrene (1,3-DNP), 1,6-dinitropyrene (1,6-DNP), 1,8-dinitropyrene (1,8-DNP), 3-hydroxy-1-nitropyrene (3-OH-1-NP) and a mixture of 6- and 8-hydroxy-1-nitropyrene (6/8-OH-1-NP) were investigated in newborn female rats. Newborn female CD rats were treated s.c. eight times at weekly intervals with a total dose of 6.3 mumol 1-NP,1,3-DNP,1,6-DNP or 1,8-DNP; control animals received only dimethylsulfoxide (DMSO). The experiment was terminated at 67 weeks. With the exception of 1,6-DNP- and 1,8-DNP-treated animals, which had average survival periods of 149 and 164 days respectively, the animals administered the other compounds did not show decreased survival. Malignant fibrous histiocytomas were observed in 12%, 100% and 100% of the rats treated with 1,3-, 1,6- and 1,8-DNP respectively. Leukemia was found in 20% and 22% of the animals treated with 1,6- and 1,8-DNP respectively. No control rats developed these tumors. Additionally, mammary tumors were induced in rats treated with 1-NP. Newborn female CD rats were similarly treated with 1-NP, 4-NP, 3-OH-1-NP, 6/8-OH-1-NP or DMSO and newborn female F344 rats were treated with 1-NP or DMSO. The experiment was terminated at 86 weeks, 1-NP and 4-NP produced mammary adenocarcinoma in CD rats. Although 1-NP did not produce mammary adenocarcinoma in F344 rats, it induced leukemia. 4-NP also induced malignant fibrous histiocytomas in CD rats. This study demonstrates that 4-NP is more carcinogenic than 1-NP and that CD rats are more susceptible than F344 rats to mammary carcinogenesis by 1-NP. Additionally, 1,6- and 1,8-DNP are more potent than 1-NP in inducing malignant fibrous histiocytomas and leukemia.

Antitumor effects of liposomes containing adriamycin on chemically-induced rat malignant fibrous histiocytoma

Malignant fibrous histiocytoma (MFH) is the most common soft tissue sarcoma. No effective chemotherapeutic agents, however, have been reported. Here we report our evaluation of the antitumor effects of liposomes containing adriamycin (LADM) against chemically-induced rat MFH. Either free adriamycin (ADM) or LADM was administered at dosages of 4.0, 8.0 or 12.0 mg/kg by intravenous injection. The tumor responded to LADM with prolonged growth delay, but equivalent doses of free ADM were less effective. Additionally, LADM prolonged the life span of rats longer than did free ADM. Also, the body weight loss was less with LADM than with equivalent doses of free ADM. In tissue distribution studies, we observed that the ADM level in the blood and in the tumor with LADM remained higher than with free ADM. These results indicate that liposomes alter in vivo ADM tissue distribution and increase antitumor activity against rat MFH with reduced toxic side effects.

[The early stages of the morphogenesis and tissue lineage of an experimental malignant fibrous histiocytoma]

Morphologically atypical cells were first detected on the 98th day after subcutaneous implantation to rats of a paraffin pellet containing 2 mg of 7,12-dimethylbenz(a)anthracene (DMBA). These cells subsequently formed groups and finally gave rise to malignant fibrous histiocytomas. Early atypical cells were located between proliferating fibroblasts and histiocytes in the center of a fibrous capsule surrounding the DMBA-pill. They exhibited a smooth cell surface, dilated rough endoplasmic reticulum, multiple Golgi complexes, and were often associated with newly formed collagen. These cells incorporated 3H-thymidine and 3H-proline intensively, and showed weak acid phosphatase activity, but no features typical for macrophages (microvilli, numerous lysosomes, high activity of acid phosphatase, nonspecific esterases, antigens recognized by monoclonal antibodies ED1 and OX-42, vital staining with trypan blue). Atypical cells also did not differentiate into muscle cells (no expression of desmin and the alpha-sarcomeric form of actin), nor into Schwann cells (no expression of S-100 protein). No point mutation of the neu gene at nucleotide 2007, which is specific for N-ethyl-N-nitrosourea and DMBA-induced malignant rat schwannoma cells, was detected by polymerase chain reaction-restriction fragment length polymorphism analyses of microscopically selected regions of individual 7 micron cryostat sections. These results support the view that malignant fibrous histiocytoma is derived from immature fibroblasts exhibiting pronounced phenotypic diversity during later stages of carcinogenesis.

Evaluation of carcinogenicity and chronic toxicity associated with orthopedic implants in mice

The carcinogenicity and chronic toxicity of 316L stainless steel, nickel, Ti-6A1-4V, hydroxyapatite (HA)-coated Ti-6A1-4V, aluminum oxide containing yttrium oxide, and zirconium oxide containing yttrium oxide were evaluated by implanting solid rods of each material in the thigh muscle of C57BL/6N mice for 24 months. Nickel alloy showed high carcinogenic and toxic potencies, whereas other materials showed no evidence of them. Tumors retaining nickel alloys were malignant fibrous histiocytoma or fibrosarcoma. In some cases, lymphomata that seemed to develop spontaneously were found around the implants because lymphocytes were known to accumulate in chronic inflammatory lesions, and this phenomenon also might be applied to lymphoma.

Pharmacodynamics of phenobarbital anesthesia and pentylenetetrazol-induced maximal seizures in a rat model of neoplastic spinal cord compression

The purpose of this investigation was to determine whether paraplegia induced by neoplastic cord compression affects the pharmacodynamics of phenobarbital general anesthesia or of pentylenetetrazol (PTZ)-induced convulsions. Paraplegic rats harboring a thoracolumbar epidural tumor, or an identical hindlimb tumor mass, received an i.v. infusion of phenobarbital until the onset of anesthesia. At that point, the phenobarbital concentrations in the CSF and serum were measured. Similarly, PTZ was infused until the onset of maximal seizures. It was found that changes related to systemic tumor growth and newly developed paraplegia due to neoplastic spinal cord compression did not attenuate the pharmacodynamics of phenobarbital. However, sustained paraplegia of 4 days' duration reduced CNS sensitivity to the hypnotic action of the barbiturate as evidenced by the higher cerebrospinal fluid phenobarbital concentration required to induce anesthesia (170 +/- 31 vs 125 +/- 20 mg/L; P < 0.05). On the other hand, sustained paraplegia did not affect brain threshold concentration for PTZ-induced seizures.

Gross and microscopic pathology of induced prostatic complex tumors arising in Lobund-Wistar rats

The necessity for additional animal models for prostate cancer has recently been stressed. The Pollard model of chemically induced prostate cancer has received attention in this regard although the histiogenetic origin of these tumors has come under question. We independently studied this model for the development of tumors in the prostate region. The tumors, all of which were adenocarcinomas, first became grossly evident 5 months after induction and ultimately occurred in 71% of the animals. Seventy-three % of the tumors involved only the seminal vesicle, 22% involved other portions of the prostatic complex as well as the seminal vesicle, and 5% were located in the coagulating gland (anterior prostate). Although the majority of tumors arose in or involved the seminal vesicle, this may still be a useful model for the study of human prostate cancer because the tumors are adenocarcinomas, occur in the large majority of animals, are hormonally induced, and have the propensity to metastasize.

Tumorigenicity of poly-L-lactide (PLLA) plates compared with medical-grade polyethylene

Poly-L-lactide (PLLA) plates, 20 x 10 x 1 mm in size, with flat surfaces, were implanted into 50 young male Wistar rats subcutaneously, and the incidence of tumors for 2 years under specific pathogen-free (SPF) conditions was evaluated. Tumors arose in 22 rats (at the implant sites in 20, and distant from the implantation site in 2). As a control, plates of medical-grade polyethylene of the same shape were implanted into 50 rats. Tumors appeared in 23 of these rats (21 at the sites of the plates, and 2 ectopically). In 30 rats given sham operations, no tumors appeared in the 2 year observation period. Histologically, all the tumors were mesenchymal malignant tumors resembling fibrosarcoma or malignant fibrous histocytoma (MFH) in humans. In 6 of the PLLA tumors and 3 of the PE tumors, bone formation was observed. There was no significant difference between the incidence of tumors caused by PLLA plates and that of tumors caused by medical-grade polyethylene plates. Macroscopically, PLLA plates retained their initial shape for 2 years. Scanning electron microscopy revealed small holes on the surfaces of the plates, and their molecular weight was reduced to 8% of the initial value.

Development of malignant fibrous histiocytoma induced by 7,12-dimethylbenz[a]anthracene in the rat: characterization of early atypical cells

Morphologically atypical cells were first detected in the adjacent connective tissue 98 days after implanting a paraffin pill containing 2 mg of 7,12-dimethylbenz[a]anthracene (DMBA) into the subcutaneous tissues of rats. These cells subsequently formed groups and finally produced gross malignant fibrous histiocytomas (MFH). Early atypical cells were located between proliferating fibroblasts and histiocytes in the center of a fibrous capsule surrounding the DMBA pill. They exhibited a smooth cell surface, dilated rough endoplasmic reticulum, multiple Golgi complexes, and were often associated with newly formed collagen. These cells incorporated [3H]thymidine and [3H]proline intensively, and showed weak acid phosphatase activity but no features diagnostic of macrophages (microvilli, numerous lysosomes, high acid phosphatase and non-specific esterase activities, antigens recognized by monoclonal antibodies ED1 and OX-42 and vital staining with trypan blue). There was no evidence that atypical cells differentiated into muscle cells (no expression of desmin or the alpha-sarcomeric form of actin) or Schwann cells (no expression of S-100 protein). No point mutation in the neu gene at nucleotide 2007, specific for N-ethyl-N-nitrosourea- and DMBA-induced malignant rat schwannomas, was detected by polymerase chain reaction (PCR)-restriction fragment length polymorphism (RFLP) analyses. These results support the view that malignant fibrous histiocytoma is derived from immature fibroblasts exhibiting pronounced phenotypic diversity during the later stages of carcinogenesis.

Immunohistochemical, quantitative immunoelectron microscopic, and DNA cytofluorometric characterization of chemically induced rat malignant fibrous histiocytoma

Malignant fibrous histiocytoma (MFH) was induced in rats by injection of 9,10-dimethyl-1,2-benzanthracene. Using cell suspensions prepared from the heterotransplanted nude mouse tumor as immunogen, a monoclonal antibody, (MAb), MEP-1, against fibroblastlike MFH tumor cells was generated. In the primary rat tumors and transplanted rat or nude mouse tumors, MEP-1 reacted specifically with the fibroblastlike cells but not with the histiocytelike cells or xanthoma cells. Anti-rat macrophage MAbs RM-1 and TRPM-3 did not stain the fibroblastlike cells, but both were reactive with the histiocytelike cells. Double stainings with both MEP-1 and RM-1 or TRPM-3 did not detect any double positive cells. Immunoelectron microscopy using these MAbs showed that the fibroblastlike cells were the major cell component of the primary and transplanted rat tumors and that their cell membrane was stained positively with MEP-1, but not for RM-1 or TRPM-3. By the double staining method using a MAb against prolyl 4-hydroxylase beta and MEP-1 or TRPM-3, this enzyme was demonstrated in MEP-1-positive cells but not in TRPM-3-positive cells. Results obtained by DNA cytofluorometry with 4,6-diamidino-2-phenylindole dihydrochloride staining or by the combined method of DNA cytofluorometry and indirect immunofluorescence, using MEP-1, RM-1, and TRPM-3, indicate that MEP-1-positive cells are neoplastic cells of rat MFH having proliferation activity. In the transplanted nude mouse tumors, no differentiation of MEP-1-positive rat tumor cells into histiocytelike cells was detected, and all histiocytelike cells were immunostained by F4/80 and most of them were positive for M5/114. These results suggest that fibroblastlike cells and intermediate cells are tumor cells of 9,10-dimethyl-1,2-benzanthracene-induced rat MFH showing differentiation toward fibroblasts and that histiocytelike cells are infiltrated macrophages.

An experimental recurrence model for malignant fibrous histiocytoma induced by 4-hydroxyaminoquinoline 1-oxide in the rat

To clarify the relationship between local recurrence of mesenchymal tumors and their malignant potentiality, we made an experimental recurrence model for malignant fibrous histiocytoma (MFH) induced by 4-hydroxyaminoquinoline 1-oxide in the rat by repeated excisional operations. By the repeated excision, the number of recurrent tumors increased, and the doubling time of tumor growth was shortened. The mean doubling time of primary tumors was 6.6 days, that of the first locally recurrent tumors was 4.3 days, and that of the second locally recurrent tumors was 3.3 days. However, mitotic count and 5-bromo-2-deoxyuridine (BrdU) labeling index did not change. This study proved experimentally that MFH shows more rapid growth through repeated local recurrences, and this experimental model may provide a better understanding of the local recurrence of MFH.

Induction of malignant fibrous histiocytoma in female Fisher rats by implantation of cyanoacrylate, zirconia, polyvinyl chloride or silicone

Five kinds of foreign bodies (silicone, cellulose, polyvinyl chloride, zirconia and alkyl-alpha cyanoacrylate) were implanted into subcutaneous tissue of female Fisher rats. Subcutaneous tumors were induced in 27.3, 54.5, 100, 63.6% of rats by silicone rubber, polyvinyl chloride, zirconia and alkyl-alpha-cyanoacrylate, respectively, but not by cellulose. Almost all tumors were composed of a mixture of cells that resembled fibroblasts characterized by the presence of numerous rough-surfaced endoplasmic reticulum and Golgi apparatus, histiocytes characterized by developed endoplasmic reticulum and abundant lysosome, myofibroblasts characterized by the presence of both myofibrils and fibroblast-like structures, and immature mesenchymal cells. In some tumors, the cells exhibited a storiform pattern. Some tumor cells were positively stained by ED2 or anti-muscle actin antibody. The features of induced tumors in rats were consistent with those of human malignant fibrous histiocytoma. A rat malignant fibrous histiocytoma transplanted into the subcutaneous tissue of the syngeneic female Fisher rats grew and metastasized to the lungs.

Biomarkers for individual susceptibility to carcinogenic agents: excretion and carcinogenic risk of benzo[a]pyrene metabolites

In rats exposed to a single intraperitoneal dose of 200 mg/kg of the environmental carcinogen benzo[a]pyrene (BP) in sunflower oil, significant individual variations in excretion of the BP activation (BP-7,8-diol) and deactivation (3-OH-BP) derivatives were found. Most rats developed peritoneal sarcomas. Only the levels of BP-7,8-diol excreted in the urine correlated directly with the latency of tumor formation. After a similar exposure to a dose of 100 mg/kg BP, Macaca fascicularis monkeys excreted smaller quantities than rats of both metabolites. After rats were given 10 intraperitoneal injections each of 10 mg/kg of BP in a water-lipid emulsion, the excreted levels of both metabolites after the first, fifth, and tenth injection were lower than those of the rats that received 200 mg/kg. BP metabolites were also detected in the urine of lung cancer patients who were heavy smokers. The applicability of monitoring the excretion of the BP metabolites to predicting individual cancer risk is discussed.

Carcinogenicity of dinitropyrenes in the weanling female CD rat

The carcinogenicities of 1-nitropyrene and 1,3-, 1,6- and 1,8-dinitropyrene were assessed in weanling female CD rats. The animals were administered one of the compounds at 10 mumol/kg body wt through intraperitoneal or intragastric administration three times a week for 4 weeks. The total cumulative dose averaged 16 mumol/animal. The experiment was ended 78 weeks following the first administration. The average survival period for the animals in the 1,6- and 1,8-dinitropyrene i.p. treated groups, due to the occurrence of life-threatening peritoneal malignant fibrous histiocytomas (MFHs) in nearly all of the animals, were 19 and 38 weeks respectively. 1,3-Dinitropyrene induced only a few MFHs. 1,8-Dinitropyrene also induced a significant incidence of leukemia. A significant increase of the incidence of mammary tumors was observed in the groups of rats treated i.p. with 1-nitropyrene, or 1,3- or 1,8-dinitropyrene, and those treated i.g. with 1,8-dinitropyrene. These results demonstrate that nitropyrenes are capable of inducing MFH, mammary tumors and leukemia in the rat.

Metastatic potential of malignant fibrous histiocytoma of myxoid or giant-cell subtype in rats

We have previously reported on the induction of rat malignant fibrous histiocytomas by 4-hydroxiaminoquinoline 1-oxide. The present study describes cell number- and time-related formation of metastatic lung nodules after i.v. injection of cell suspensions containing various numbers (10(3) to 10(5)/ml) of myxoid or giant-cell subtype malignant fibrous histiocytoma cells. The metastatic potential of the myxoid subtype of rat malignant fibrous histiocytoma was significantly enhanced by i.v. injection of tumor cells selected from metastatic lung nodules and was further increased by repeating the selection procedure more than 7 times. In contrast, the growth activity of subcutaneous transplants of tumor fragments obtained from metastatic lung nodules derived from myxoid subtype did not differ from that of parent malignant fibrous histiocytomas.

Histopathology of N-methyl-N-nitrosourea-induced mesenchymal tumours of the rat urinary bladder

The present study reports the induction, histopathology, immunocytochemistry, growth pattern and proliferative behaviour of mesenchymal tumours of the urinary bladder of rats induced by a single intravesical dose (5 mg/kg/body weight) of N-methyl-N-nitrosourea (MNU). In 14 of 283 female Wistar rats (incidence: 4.9%). 16 non-epithelial tumours had developed after an experimental period of 14 months. The most common histological type induced was of fibrohistiocytic origin (eight benign-appearing and three malignant fibrous histiocytomas). Furthermore, two pure histiocytomas (one benign and one malignant) and three capillary and cavernous haemangiomas were produced. Since no metastases occurred and no clear-cut distinction between a merely expansive and a truly invasive growth was possible, the diagnosis of malignancy was based on the degree of cellular atypia and the mitotic activity. The benign-appearing fibrous histiocytomas showed a mean mitotic index of 0.06% and the malignant fibrous histiocytomas of 0.34%. The mitotic activity of the malignant histiocytoma was threefold (0.78%) as high as in the benign-appearing histiocytoma (0.25%). There exist close morphological similarities between the induced mesenchymal tumours in the rat and those occurring in the human bladder. Although the spectrum of histological types of mesenchymal tumours seen in the rat bladder was narrower than that encountered in man, MNU seems suitable for further studying the histogenesis, histopathology and biology of experimentally induced non-epithelial bladder neoplasms to gain information for a better understanding of the pathogenesis of human disease.

Chemically induced transplantable malignant fibrous histiocytoma of the rat. Analyses with immunohistochemistry, immunoelectron microscopy and [3H]thymidine autoradiography

Malignant fibrous histiocytoma was produced in rats by injection of 9,10-dimethyl-1,2-benzanthracene into their knee joints. The original tumors consisted mainly of fibroblast-like cells and histiocyte-like cells, often intermixed with bizarre giant cells, and they frequently showed the storiform-pleomorphic pattern. By immunohistochemistry, anti-rat macrophage monoclonal antibodies, TRPM-3, RM-1, and Ki-M2R, and anti-rat leukocyte common antigen reacted to the histiocyte-like cells but not to the fibroblast-like cells. By the single cell cloning method, we established six tumor cell lines, none of which reacted with the anti-rat macrophage monoclonal antibodies, possessed any Fc receptors, or conducted immune phagocytosis and Latex particle phagocytosis. The ultrastructure of the cloned tumor cells resembled that of long-term cultured dermal fibroblasts. Collagen production by the tumor cells was demonstrated immunohistochemically with a monoclonal antibody for type I collagen. Inoculation of the cloned tumor cells into rats produced tumors with the histology of malignant fibrous histiocytoma and induced prominent macrophage infiltration. In the rat tumors produced by the inoculation of [3H]thymidine labeled cells, no reactivity of tumor cells with the anti-rat macrophage monoclonal antibodies was observed. Transplantation of the cultured rat tumor cells into nude mice produced tumors similar in histology to the original rat malignant fibrous histiocytoma. Tumor cells in nude mice induced marked macrophage infiltration as detected by immunohistochemistry with the anti-mouse macrophage monoclonal antibody F4/80. No differentiation of tumor cells into macrophages was detected, since no cells were stained with biotinylated anti-rat macrophage monoclonal antibody TRPM-3. By the flash labeling method with [3H]thymidine, infiltrating macrophages in the nude mouse tumors were proved to derive from the bone marrow of the host animals. These results indicate a possible experimental reproduction of malignant fibrous histiocytoma by proliferation of malignant fibroblasts or their related cells in combination with macrophage infiltration.

Immunohistochemical study of 4-hydroxyaminoquinoline 1-oxide-induced rat malignant fibrous histiocytoma

The primary focus of this experiment was on the investigation of localizations of alpha 1-antitrypsin (alpha 1-AT), alpha 1-antichymotrypsin (alpha 1-ACT), fibronectin (FN) and lysozyme (LY) in tumor cells of experimental malignant fibrous histiocytoma (MFH). The induction of MFH was conducted by injecting Fischer 344 rats with 4-hydroxyaminoquinoline 1-oxide (4-HAQO). In 46 out of 50 rats, tumors were generated, all of which were diagnosed as MFH and classified into 5 subtypes, according to their histological properties. The presence of alpha 1-AT, alpha 1-ACT and FN in all MFH tumor cells was observed in the tumor cells of various types. Especially, fibroblast-like, histiocyte-like and Touton and/or Epulis type giant cells showed strong reactivity. However, positive reaction of LY in MHF tumor cells was very weak, or the reaction was negative. These findings are consistent with those of human MFH.

Malignant fibrous histiocytoma. Induced by thorium

Thorium dioxide is a deleterious substance that was employed as a vascular contrast medium during the early 20th century. Our report entails a unique neoplastic complication of thorium administration.

Cell line of mouse malignant fibrous histiocytoma with spontaneous metastatic potential

A new murine malignant fibrous histiocytoma (MFH) cell line was established from a 4-hydroxyaminoquinoline 1-oxide-induced MFH. This cell line was followed by a contiguous sheet, and a confluent monolayer was established after 12 days incubation. These cells could be serially transplanted into the subcutaneous tissue of mice, the success rate becoming 100% after the 9th passage. Transplanted tumors demonstrated rapid growth and displayed a high potential for metastasis to the lung after the 16th passage. And a 100% lung metastasis rate was observed for MFH cells after the 20th passage. Histologically, these metastatic tumors retained features of the primary tumor.

[Unusual cutaneous angiofibromatosis following gold therapy of primary chronic polyarthritis]

An unusual case of late cutaneous intolerance reaction following gold therapy for rheumatoid arthritis is reported. In keloidlike angiofibromatoid lesions that were spread over the upper part of the trunk and the arms, perivascular macrophages carrying gold deposits inside lysosomes were detected with two recently introduced methods--energy-dispersive X-ray microanalysis (EDX) and electron spectroscopic imaging (ESI)--for definitive ultrastructural localization.

Metabolism and biological effects of nitropyrene and related compounds

The aim of this project was to compare the carcinogenicities of 1,3-, 1,6-, and 1,8-dinitropyrene, 1-nitropyrene, and the metabolic phenolic derivatives of 1-nitropyrene. The biochemical goal was to establish how these inert compounds are converted metabolically, by target tissues, to reactive species that can alter the DNA of the susceptible cell. The comparative tumorigenicities were assessed by the use of female CD rats. Control groups consisted of animals that had been given only the solvent, dimethylsulfoxide, which has a low toxicity, to maximize solubility. Equimolar doses (1.7 mumole/ml; 10 mumole/kg body weight) of the compounds were administered to weanling rats by intraperitoneal injection, or by intragastric intubation, three times each week for four weeks, for a total dose of 16 mumoles. Newborn animals were treated by subcutaneous injection of the 1,3-, 1,6-, or 1,8-dinitropyrene or 1-nitropyrene within 24 hours of birth, and at seven weekly intervals, for a total dose of 6.3 mumoles. The possible carcinogenicities of phenolic metabolites of 1-nitropyrene were examined by subcutaneous treatment of newborn animals, and at seven weekly intervals, with 1-nitropyrene, 3-hydroxy-1-nitropyrene, or a mixture of 6-hydroxy-1-nitropyrene and 8-hydroxy-1-nitropyrene (70 mumoles/ml; 100 mumoles/kg body weight; total dose, 63 mumoles). The relative carcinogenicity of 1-nitropyrene in the female Fischer 344 rats was established by the concurrent treatment of appropriate animals. The smaller, inbred Fischer rats received a total dose of 40 mumoles. Subcutaneous and intraperitoneal treatments of weanling female CD rats (70 mumoles/ml; 100 mumoles/kg body weight; 5 weekly injections) with 1-nitropyrene were carried out to explore possible differences because of the different routes of administration in animals of the same age. Dinitropyrenes are much more carcinogenic than 1-nitropyrene (1,6- greater than 1,8- greater than 1,3-dinitropyrene greater than 1-nitropyrene). Phenolic derivatives of 1-nitropyrene are no more carcinogenic than the parent compound. The most likely tumors to be induced in this animal model are malignant fibrous histiocytomas (MFHs), mammary gland tumors, and leukemias. Animals treated with 1,6- or 1,8-dinitropyrene by subcutaneous injection yielded MFHs at the site within 15 weeks of the first injection (i.e., at 15 weeks of age), and this did not permit them to survive more than 20 to 25 weeks. Leukemia developed in these animals within this brief period, but mammary gland tumors were observed only when survival of the animal was not limited by the formation of the more aggressive MFHs.(ABSTRACT TRUNCATED AT 400 WORDS)

Histopathological and immunohistochemical studies on nickel sulfide-induced tumors in F344 rats

Twenty-five tumors induced in F344 male rats were examined histologically and immunohistochemically using antibodies against myoglobin, myosin, desmin and cathepsin B. Eight were from rats which had been given intramuscular (im) injection and 17 were from rats which had been given subcutaneous (sc) injection of 5 mg of Ni3S2. Among 10 rhabdomyosarcomas, myoglobin was detectable in 3, myosin in 8, and desmin in all, but cathepsin B was present in none. Out of 8 malignant fibrous histiocytomas, cathepsin B was detectable in all, but the other antigens were absent. In a leiomyosarcoma, only desmin was detected. In two fibrosarcomas, none of the markers were detected. In four undetermined tumors, one reacted only with anti-desmin antibody, two with only anti-cathepsin B antibody, and one with none of the antibodies. Of the three myogenic markers utilized in this study, anti-desmin antibody appeared to be the most sensitive. Cathepsin B was found mainly in the histiocytic cells of malignant fibrous histiocytoma. Thus, desmin appears to be particularly valuable in distinguishing immature myogenic tumors from other primitive tumors, while cathepsin B is useful in distinguishing malignant fibrous histiocytoma from other pleomorphic mesenchymal tumors.

Induction of subcutaneous tumors in rats by 3,7- and 3,9-dinitrofluoranthene

Two dinitrofluoranthenes (DNFs) derived from 3-nitrofluoranthene were purified to over 99%, and tested for tumorigenicity in F344/DuCrj male rats. Rats were inoculated s.c. with 0.05 mg 3,7- or 3,9-DNF twice a week for 10 weeks. All 21 rats given 3,7-DNF and 10 of 11 rats (91%) given 3,9-DNF developed tumors at the injection site by 48 weeks after the first injection. Twenty of the 21 tumors induced by 3,7-DNF and seven of the 10 tumors induced by 3,9-DNF were classified as malignant fibrous histiocytoma, but one tumor in the 3,7-DNF-treated group and three tumors induced by 3,9-DNF showed typical features of rhabdomyosarcoma. The first tumors in 3,9-DNF-treated rats appeared on day 88 (on day average 117), 10 weeks earlier than in 3,7-DNF-treated ones (on day average 186).

Tumorigenicity test of 1,3- and 1,8-dinitropyrene in BALB/c mice

1,3-Dinitropyrene (DNP) and 1,8-DNP (CAS: 42397-65-9) are very potent mutagens and induce a frameshift-type mutation in the Salmonella test system. Each compound was tested for tumorigenicity in BALB/c mice by sc inoculation of 0.05 mg of the compound once a week for 20 weeks. Tumors developed at the site of injection of 1,8-DNP in 6 of 15 mice up to 60 weeks after the first injection. The incidence of tumors was statistically significant at a P-value of less than .05 but not of less than .01. Therefore, the carcinogenicity of 1,8-DNP in BALB/c mice was concluded to be weaker than that of benzo[a]pyrene [(BP) CAS: 50-32-8], which induced a 100% tumor incidence when it was injected at the same dose as that of 1,8-DNP. No tumors occurred at the injection site in mice given 1,3-DNP. Most of the tumors induced by 1,8-DNP and BP showed histologic features characteristic of malignant fibrous histiocytoma.

Malignant fibrous histiocytoma induced by intra-articular injection of 9,10-dimethyl-1,2-benzanthracene in the rat. Pathological and enzyme histochemical studies

Malignant fibrous histiocytoma (MFH) was produced by injection of 9,10-dimethyl-1,2-benzanthracene (DMBA) into the rat knee joint. The tumor was observed in or around the knee in nearly all the animals 13 to 36 weeks after the initial DMBA administration. Histologically, these lesions were of the storiform-pleomorphic type (39/58, 67.2%), myxoid type (9/58, 15.5%), or giant cell type (8/58, 13.8%). Six cell types reported in human MFH were confirmed and phagocytosis of 0.81-micron latex particles by histiocyte-like cells was noted by electron microscopic examination. Acid phosphatase, beta-glucuronidase, and alpha-naphthyl acetate esterase were positive in enzyme histochemical examinations. Acid phosphatase activity was electron microscopically noted primarily in the lysosomes and the Golgi apparatus of the histiocyte-like cells. Cells from the storiform-pleomorphic (M1) and myxoid (M2) type tumors were serially transplanted subcutaneously in the back of the rats, and are now at the thirtieth and fortieth passage, respectively. They also were studied by enzyme histochemical and electron microscopic techniques. Our observations suggested an undifferentiated mesenchymal cell origin of MFH. Transplantable MFH can be produced in rats by intra-articular injection of DMBA, and lesions thus produced are a useful experimental model for the investigation of the histogenesis and the effect of chemotherapy of MFH.

Experimentally-induced jaw sarcoma in the rat

Jaw bones differ embryologically from limb bones and the axial skeleton as they are derived from migrating neural crest cells and are not preformed in cartilage as are the latter bone types. The purpose of the present study was to determine whether this embryologically different nature implied a different response to a locally applied carcinogenic compound, 4-hydroxyamino-quinoline-1-oxide; this within the context of elucidating why human jaw osteo- and fibrosarcomas behave differently from identical tumours elsewhere in the skeleton. Rat mandibles were exposed to the carcinogen. Of the 5 rats used, 3 developed tumours which were however histologically identical to the tumours experimentally induced in the limb bones by the same carcinogenic agent. As a consequence, it is concluded that the embryologically different nature of the jaw bone does not imply that local exposure to a carcinogenic agent induces other kinds of tumours as are seen in the extragnathic skeleton.

Malignant fibrous histiocytoma

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Cutaneous signs of systemic toxicity due to dioxins and related chemicals

The controversy about dioxin effects on human health received a great deal of attention recently when the State of Missouri was declared to have a dioxin crisis. However, dioxin and several related chemicals are widespread throughout the world. Cutaneous signs play an important part in evaluating toxicity of dioxin and similar chemicals. Chloracne is the most sensitive indicator of significant dioxin exposure. Porphyria cutanea tarda and hyperpigmentation are other known cutaneous effects, and malignant fibrous histiocytomas of the skin may possibly be associated, although data are inconclusive on this point. The AMC Council on Scientific Affairs recommended that all physicians become familiar with chloracne and other toxic effects of dioxin. Dermatologists, especially, should be aware of the problem and may discover early cases of previously unsuspected exposure to this group of chemicals.

Experimental-induced sarcomas after intra-articular injection of 9-10-dimethyl-1-2-benzanthracene

The authors describe an experimental study on rabbits whereby the development of sarcomas was induced following injection into the knee joint with 9-10-dimethyl-1-2-benzanthracene. The results of the experiment are in contrast to those of other authors as no "synovialoma" or synovial sarcoma developed but only morphological patterns which might belong to malignant fibrous histiocytoma and occasionally fibrosarcoma. In accord with our results the hypothesis is discussed that all malignant mesenchymal neoplasias result from a not clearly identifiable pluripotent mesenchymal stem cell.

Experimental studies on malignant fibrous histiocytomas in rats. I. Production of malignant fibrous histiocytomas by 4-hydroxyaminoquinoline 1-oxide in bone of Fischer 344 strain rats

Malignant fibrous histocytomas (MFHs) were induced by a single injection of 4-hydroxyaminoquinoline 1-oxide (4-HAQO) into periosseous tissue of the tibia or by inserting solid 4-HAQO into the bone marrow of the tibia of male Fischer 344 rats. Periosseous MFHs were induced by doses of 2 mg and 4 mg of 4-HAQO per rat in three of 13 (23%) rats and nine of 13 (69%) rats, respectively, at 18 to 27 weeks after treatment. Bone MFHs were induced by doses of 2 mg, 4 mg, and 8 mg of 4-HAQO per rat in one of 15 (7%) rats, 11 of 18 (61%) rats, and 12 of 14 (86%) rats, respectively, after 18 to 29 weeks. Radiologic examination of bone MFH revealed bone destruction with or without a periosteal reaction, pathologic fracture, and tumor invasion into periosseous soft tissue. The serum alkaline phosphatase levels were elevated in rats with bone MFHs. Histologically, these MFHs were divided into fibrous, giant cell, myxoid, and inflammatory types. The incidence of fibrous MFHs was highest. Lung and inguinal and/or retroperitoneal lymph node metastases were observed in some rats, and these were of the fibrous type. These MFHs were quite similar to those in humans histologically and electron microscopically. This work establishes an animal model for studying the pathogenesis of bone MFH.

Malignant fibrous histiocytomas induced by 4-(hydroxyamino)quinoline 1-oxide in rats

Subcutaneous and bone malignant fibrous histiocytomas (MFH) were induced in high incidence in rats by 4-(hydroxyamino)-quinoline 1-oxide (4-HAQO). Subcutaneous MFH were induced locally by repeated weekly injections of 1 mg 4-HAQO/rat for 4 weeks. Between 16 and 48 weeks after the final treatment, 13/15 (87%) male noninbred Wistar rats developed tumors. The histologic subtypes of these tumors were as follows: 11 fibrous, 1 myxoid, and 1 giant cell. Bone MFH were induced between 18 and 25 weeks by implantation of 4-HAQO (8 mg/rat) into the bone marrow of the tibia in 12/14 (86%) male noninbred Fischer 344 rats. The histologic subtypes of these tumors were as follows: 6 fibrous, 4 myxoid, and 2 giant cell. Morphologically, these MFH appeared similar to human MFH.

Carcinogenicity of 2-amino-4-(5-nitro-2-furyl) thiazole in rats by oral and subcutaneous administration

Female Fischer rats were divided into two groups and fed either basal diet or basal diet containing 0.166% 2-amino-4-(5-nitro-2-furyl) thiazole for 52 weeks followed by basal diet for an additional 16 weeks. Our of the 24 rats fed 2-amino-4-(5-nitro-2-furyl) thiazole, 23 had forestomach tumors, four had fibroadenomas and two had adenocarcinomas in the mammary glands, two had renal pelvic carcinomas, five had papillomas and six had carcinomas in the bladder, and two had cutaneous tumors. None of the 10 rats fed basal diet developed tumors. In another study, two-week-old Fischer rats of both sexes were injected s.c. once a week for the first eight weeks with 2-amino-4-(5-nitro-2-furyl) thiazole at a dose of 10 mg/kg and then 1.4 mg/rat for an additional 46 weeks. The control rats were injected with solvent (dimethyl sulfoxide: water, 1:1) only. The experiment was terminated at the end of 58 weeks. Malignant fibrous histiocytomas were found in five out of eight male rats and four out of 11 female rats, and an angiosarcoma was found in one out of eight male rats injected with 2-amino-4-(5-nitro-2-furyl) thiazole. None of the control rats developed tumors.

Carcinogenicity in rats of the mutagenic compounds 1-nitropyrene and 3-nitrofluoranthene

1-Nitropyrene and 3-nitrofluoranthene are present in diesel exhaust, in pollutants in air, and were also present in certain xerographic toners and copies. Their carcinogenicities were studied in male F344/DuCrj rats by subcutaneous injection. Sarcomas, mainly malignant fibrous histiocytomas at the site of injection were induced in 8 to 17 (47%) rats by 1-nitropyrene and in 4 of 10 (40%) rats by 3-nitrofluoranthene. Some tumors were serially transplantable in the same strain of rats.