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Copyright of Etlik Veteriner Mikrobiyoloji Dergisi is the property of Veteriner Kontrol Merkez Arastirma Enstitusu and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

The aim of this study was to record the distribution and the spatial and temporal trends of canine transmissible venereal tumor (CTVT) in pet dogs; and identify the potential factors that are playing important role in disease spread. A questionnaire-based study was conducted to identify the conditions and circumstances of CTVT affected dogs that presented to veterinary practices over a 12-month period. The practices were conveniencesampled on the basis of voluntary participation. Forty practices were approached, and veterinarians from 24 practices agreed to participate. Data were provided on 96 original presentations, excluding revisits, of which 47.92% were intact males and 52.08% were intact females with the mean age of 3.98 years. Moreover, further 96 controls were selected from the same clinical practices with same parameters. Among the dogs meant for different purposes, guarding purpose dogs were found more affected (n=59). While among the dog breeds, Labrador were over-represented (n=26) followed by mongrel dogs (bully, n=23). In winter season, higher number of cases (n=34; from November to February) was recorded as compared to other seasons. To explore further important features, non-linear categorical PCA was employed. Prominently canine populations in the vicinity were found to be more varied. This is the first epidemiological study done in Pakistan that has identified some novel trends and circumstances regarding the CTVT. [ABSTRACT FROM AUTHOR]

A two years old non-descript bitch was presented to the Veterinary Clinical Complex, College of Veterinary Sciences and Animal Husbandry, Central Agricultural University, Jalukie, Nagaland with the history that the bitch was mated couple of days back and after bleeding was seen from the vagina for the last two weeks. Anamnestic data revealed normal rectal temperature of 102 °F. Upon clinical examination, it was found that there was a multilobular typical cauliflower shaped tumerous like growth projecting from the vulva. Impression smear of tumour cell was prepared and was observed under oil immersion microscope. Cytological evaluation showed high cellularity and presence of large number of pleomorphic cells, anisokaryosis with multiple nucleoli and coarse chromatin, light basophilic cytoplasm and abundant number of vacuolated cytoplasm, all conclusive of cytological diagnosis of CTVT. Chemotherapy with vincristine sulfate @ 0.025 mg/kg BW was administered weekly for 4 weeks and found that the tumour mass subsided without any complaint of further reoccurrence. [ABSTRACT FROM AUTHOR]

Background: Interferons (IFNs), signaling proteins produced by host cells, are secreted in response to pathogen activity as well as to tumor cells, and display antiviral, antiproliferative, and immunomodulatory effects. Recombinant feline interferon omega (rFeIFN-ω) has in vitro growth inhibition activities on various canine and feline tumor cell lines. Canine transmissible venereal tumor (CTVT) is used as an animal model for immunotherapy due to its specific growth phase. Previous studies have usually focused on the interaction between tumor infiltrating lymphocytes (TILs) and CTVT cells. However, the specific effects of rFeIFN-ω on CTVT cells remains poorly defined.Aims: The aims of this study, therefore, were to evaluate the in vitro effect of rFeIFN-ω on primary CTVT cells and to study the mRNA expression of apoptotic genes and drug resistance genes.Materials and Methods: Purified CTVT cells were treated with various concentrations of rFeIFN-ω and the viability of the cultured cells was ascertained at 24, 48, and 72 h post treatment (hpt) and a dose-response curve plotted. The mRNA expression of apoptotic (BAX and BCL-2) and drug resistance (ABCB1 and ABCG2) genes was performed by reverse transcription quantitative real-time PCR at 72 hpt.Results: rFeIFN-ω displayed an effect against CTVT cell viability, which decreasing viability in a dose-dependent manner within 72 hpt. The relative mRNA expression of BCL-2 was upregulated only at a rFeIFN-ω concentration of 104 IU/100 μl. However, higher concentrations of rFeIFN-ω gave a higher level of relative mRNA expression of ABCB1 transporter gene.Conclusion: This study provided the information of in vitro effect of rFeIFN-ω on CTVT cell viability in a dose dependent manner, as well as, the alteration of BCL-2 and ABCB1 gene expression after treatment. These results encourage future in vivo studies to evaluate the potential efficacy of this treatment in CTVT cases.

Canine transmissible venereal tumours (CTVT) are the most commonly diagnosed tumours in veterinary hospitals. CTVT is morphologically classified as a round cell tumour, although the exact origin of the cells is unknown. Immunohistochemical studies have suggested histiocytic and mesenchymal origin. CTVT can be classified as lymphocyte-like, plasmocyte-like, and mixed according to their cytomorphological features. The treatment of choice for CTVT is chemotherapy with vincristine sulphate applied weekly; this produces a good prognosis. However, an increase in the number of chemotherapy applications and adjuvant therapies has become common. The aim of this study was to determine the association of cytomorphological types of CTVT with resistance and partial resistance to vincristine sulphate and the possible need for a large number of chemotherapy sessions. A retrospective study of a 24-month period evaluated 46 diagnosed and treated cases of CTVT. It was concluded that there is a higher prevalence of plasmacyte-like, followed by mixed and lymphocyte-like CTVT. The cytomorphological type did not differ in relation to the response to the treatments with vincristine sulphate and the number of chemotherapy sessions necessary for CTVT regression has increased by factors not yet elucidated.

The canine transmissible venereal tumour (CTVT) is a transmissible cancer that is spread naturally between dogs, with the ability to develop and evade the immune system, despite strict immune surveillance of the host. Furthermore, molecular signalling between cells of the immune system and the tumour microenvironment appear to influence the behaviour and development of the tumour. Thus, this study aimed to quantify the expression of genes related to the immune system such as IL‐6, IFN‐γ, and TGF‐β, as well as angiogenic factors (VEGF, CXCR4), in CTVT cells in vivo and in vitro (primary culture), correlating with the clinical response of the animals treated with vincristine. As expected, the most prevalent subtype was plasmacytoid cells, although lymphocytic cells were also found, indicating the possibility of polyclonality. When we compared the gene expressions of IFN‐γ and IL‐6, we mostly found low expression, concluding that MHC expression was probably not occurring in tumour cells, and no activation of immune cells to eliminate the tumour. The TGF‐β gene was normal in the majority of animals but demonstrated decreased expression in vincristine resistant animals, leading to the hypothesis that the concentration of tumour‐derived TGF‐β was affecting and even suppressing the real TGF‐β expression, favouring tumour proliferation and progression in these cases. VEGF expression was extremely high, demonstrating its angiogenic role in tumour growth, while CXCR4 was decreased, possibly because of CTVT’s low metastatic potential. Thus, we concluded that the tumour microenvironment, together with the immune system of the host, influences CTVT, presumably altering its tumorigenesis and the animal’s clinical response to treatment. [ABSTRACT FROM AUTHOR]

Primary nasal canine transmissible venereal tumor (CTVT) without genital affection is uncommon. The aim of this report was to describe the primary nasal CTVT findings and CT staging in 4 dogs with different cytological phenotypes. Three male dogs and 1 bitch were evaluated for their chronic histories of sneezing, snoring, mucopurulent nasal discharge and nasal deformation. Cytological examination of nasal secretions suggested CTVT, confirmed by histopathological examination and LINE-1/c-myc. Males had the plasmacytoid phenotype of CTVT, and the bitch had the lymphocytoid phenotype. CTVT were staged based on the CT findings using modified Adams staging system. The bitch was classified as stage 1, 2 males were classified as stage 3 and 1 male as stage 4. All dogs had a complete tumoral remission after chemotherapy. Plasmacytoid phenotype was identified in cases with most important damage of the nasal cavity. However, the cytological type did not affect the response to chemotherapy. [ABSTRACT FROM AUTHOR]

Canine transmissible venereal tumour (CTVT) has been transmitted by cell transplantation from dog to dog, for over 10 000 years. Although initial studies report a single genetic origin for CTVT, recent samples from around the world reveal high genetic diversity. An elevated number of polymorphisms have been determined in mitochondrial DNA (mtDNA) of CTVT. The recent discovery of mtDNA transference from the host into tumoural cells could be a novel source of genetic diversity in CTVT. The aim of this study was to determine the presence of host mtDNA in samples of CTVT in Mexican dogs. Genotyping of 49 samples of CTVT and 49 samples of blood cells pertaining to affected dogs was performed by direct sequencing from the mtDNA D-loop region. Exogenous mtDNA was observed in 6% of the analysed tumours. This is the first investigation reporting the prevalence of exogenous mtDNA in CTVT in the Mexican dog population. [ABSTRACT FROM PUBLISHER]

Copyright of Pesquisa Veterinaria Brasileira is the property of Colegio Brasileiro de Patologia Animal - CBPA and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Canine transmissible venereal tumor (CTVT) is the only naturally contagious tumor that is transmitted during coitus or social behaviors. Based on the tumor's location, the diagnosis of genital TVT (GTVT) is comparably easier than those in the extragenital area (ETVT) that are more easily incorrectly diagnosed. Fortunately, CTVT cells contain a specific long interspersed nuclear elements (LINE), inserted upstream of the myc gene, allowing a diagnostic polymerase chain reaction (PCR) based detection assay. The objectives of this study were aimed to improve the diagnostic accuracy by applying the diagnostic LINE1-c-myc PCR assay and fine needle aspiration (FNA) collection in direct comparison with standard cytological and histopathological analyses. Seventy-four dogs, comprised of 41 and 31 dogs with tumor masses at their external genitalia and extragenital areas (e.g. skin and nasal cavity), respectively, were included in this study. The signalment of these 65 dogs and clinical history of 20 client-owned dogs were collected. Samples were taken by biopsy for both histopathological examination and FNA for cytological examination and diagnostic PCR. The PCR products from 10 apparently CTVT samples were purified and sequenced. Sixty-one CTVT cases were diagnosed by cytological and histological analyses, but 65 were positive by the PCR assay. Overall, the PCR assay improved the accuracy of diagnostic CTVT results, especially for the more difficult ETVT tumors. Moreover, this PCR-based approach can facilitate the decision as to discontinue chemotherapy by discrimination between residual tumor cell masses and fibrotic tissue. [ABSTRACT FROM AUTHOR]

Abstract: Microarray transcriptome study in cancer has been commonly used to investigate tumorigenic mechanisms. The unique growth pattern of spontaneous regression (SR) after progressive (P) growth in canine transmissible venereal tumor (CTVT) provides a valuable cancer model to study the genome-wide differences in samples between the two stages of growth. In this study, Affymetrix analysis was performed based on the canine genome to compare the gene expression profiles of CTVT P- and SR-phase tumors. A total of 459 (278 up-regulated and 181 down-regulated) genes were identified as being differentially-expressed during the SR phase by the 2-fold method. Further analysis of these genes revealed that the expression of three genes associated with IL-6 production –TIMD-4, GPNMB and PLTP – was significantly higher in SR-phase tumors than in P-phase tumors; these results were also confirmed by real time RT-PCR in tumor tissues of beagles. In addition, we found that Th17-related genes were over-expressed in the SR phase, suggesting autoimmune responses involvement in tumor regression. Although the interaction between CTVT and host immunity were partially investigated in previous studies, our results enable us to gain new insight into the genes and possible mechanisms involved in tumor regression and reveal potentially useful targets for cancer therapy. [Copyright &y& Elsevier]

The canine transmissible venereal tumor (CTVT) is a transplantable cancer with the ability evade the immune system, despite strict immune surveillance of the host; in this context, the relationship between inflammatory infiltrate and CTVT prognosis is not entirely understood. Natural canine transmissible venereal tumors of 22 dogs were evaluated for tumor/host interaction through clinical and epidemiological data, cyto-histopathological and cytogenetic findings and, mainly, cell-mediated immune response. We performed analysis on dogs with naturally acquired disease to provide information from the study of CTVT biology in its natural course, as the clinical evolution of the natural tumor in the host is not yet as well known as in the laboratory. Populations for T cell labeling (CD3 + CD4 + CD8 + ), B cells, NK cells, and macrophages were analyzed by flow cytometry in blood and tumor samples and expressions of MHC class I and class II molecules were quantified by immunohistochemistry and compared mainly between the phases of progression and regression in the natural CTVT. Dogs were also treated with vincristine sulfate and evaluated for chemotherapeutic response. Chemotherapy was effective in 88% of cases and there was no recurrence of the disease 12 months after the cure. Tumor cells displayed a numerical chromosomal variation between 54 and 72, not correlating with the host genotype. Although a greater expression of MHC molecules [18.6 ± 5.8% class I (P < 0.004) and 38.5 ± 6.5% class II (P < 0.003)] was observed in the regression phase, no significant effect was observed between the clinical phase of the tumor and cellular immune response in the analysis by flow cytometry (P > 0.05). We also found no correlation between cytological subtype of the tumor (plasmacytoid, lymphocytoid and mixed) and cellular immune response, suggesting that there is no difference in tumor immunogenicity. Here, we found no immunological evidence to support the theory of the immune-induced complete spontaneous regression in CTVT., (Copyright © 2022. Published by Elsevier Ltd.)

Background: Chemokines play multiple roles in the development and progression in a variety of tumors. Chemokine (C-X-C motif) ligand 7 (CXCL7) has been found associated with pro-inflammatory responses, but its role in cancer growth remains unclear. Our previous study showed that R phase tumor infiltrating lymphocytes (TILs) produced large amounts of interleukin (IL)-6 which antagonized transforming growth factor (TGF)-β derived from CTVT to diminish the immune-suppressive microenvironment. Now we intend to determine the expression pattern of CXCL7 and the role of IL-6/TGF-β in CXCL7 induction during spontaneous progressive (P) and regressive (R) phases in canine transmissible venereal tumor (CTVT). Results: We have demonstrated that CXCL7 expressed at high level in P phase and down-regulated in R phase by western blot and real-time PCR. This suggested that CXCL7 expression was negatively correlated with the tumor growth. Co-culturing TILs with CTVT cells was found to reduce CXCL7 expression, while adding IL-6 blocking antibody reversed it. Moreover, in P phase CTVT, while IL-1β and TGF-β had no obvious effect on CXCL7 expression, IL-6 was found significantly to reduce CXCL7 expression in a dose-dependent manner. The mRNA expression results of CXCL7 receptor, CXCR2, further confirmed the effects of IL-6 concentration on the CXCL7 expression. Conclusion: CXCL7 overexpression might be associated with the progressive growth of CTVT. The results shown here also suggest the role of CXCL7 in cancer development and the potential as the anti-cancer therapeutic target. [ABSTRACT FROM AUTHOR]

Canine transmissible venereal tumor (CTVT) is the only neoplasm that can be spread among dogs through cell transplantation. Therefore, this tumor does not originate from host cell transformation. Although CTVT has a monophyletic origin, several studies have shown the presence of genetic diversity which was probably acquired after the development of its original clone. To investigate the genetic diversity of CTVT in Mexico and its relation with CTVTs disseminated worldwide, we sequenced a fragment of mitochondrial DNA in 50 tumor samples and matched blood samples from dog hosts from Mexico. We found ten new haplotypes in tumor samples, which were all distinct from their matched host. The TVT1 haplotype was the most frequent in our samples, suggesting that it could be the origin of the others. We found that haplotypes in Mexico and other countries are distributed in two well-defined clusters. Our data also suggest a close relationship among American haplotypes (Mexico, USA, Chile and Brazil). Interestingly, these American haplotypes were also closely related to Asian haplotypes. Taking into account the estimated timing of the origin of CTVT, we propose that CTVT might have originated in Asia; consequently, haplotypes currently present in America could descend from Asiatic lineages. [ABSTRACT FROM AUTHOR]

Abstract: Immunization with xenogeneic DNA is a promising cancer treatment to overcome tolerance to self-antigens. Heat shock protein 70 (HSP70) is over-expressed in various kinds of tumors and is believed to be involved in tumor progression. This study tested a xenogeneic chicken HSP70 (chHSP70) DNA vaccine in an experimental canine transmissible venereal tumor (CTVT) model. Three vaccination strategies were compared: the first (PE) was designed to evaluate the prophylactic efficacy of chHSP70 DNA vaccination by delivering the vaccine before tumor inoculation in a prime boost setting, the second (T) was designed to evaluate the therapeutic efficacy of the same prime boost vaccine by vaccinating the dogs after tumor inoculation; the third (PT) was similar to the first strategy (PE), with the exception that the electroporation booster injection was replaced with a transdermal needle-free injection. Tumor growth was notably inhibited only in the PE dogs, in which the vaccination program triggered tumor regression significantly sooner than in control dogs (NT). The CD4+ subpopulation of tumor-infiltrating lymphocytes and canine HSP70 (caHSP70)-specific IFN-γ-secreting lymphocytes were significantly increased during tumor regression in the PE dogs as compared to control dogs, demonstrating that specific tolerance to caHSP70 has been overcome. In contrast, no benefit of the therapeutic strategy (T) could be noticed and the (PT) strategy only led to partial control of tumor growth. In summary, antitumor prophylactic activity was demonstrated using the chHSP70 DNA vaccine including a boost via electroporation. Our data stressed the importance of DNA electroporation as a booster to get the full benefit of DNA vaccination but also of cancer immunotherapy initiation as early as possible. Xenogeneic chHSP70 DNA vaccination including an electroporation boost is a potential vaccine to HSP70-expressing tumors, although further research is still required to better understand true clinical potential. [Copyright &y& Elsevier]

Tasmanian devil facial tumor disease (DFTD) and canine transmissible venereal tumor (CTVT) are the only known naturally occurring clonally transmissible cancers. These cancers are transmitted by the physical transfer of viable tumor cells that can be transplanted across histocompatibility barriers into unrelated hosts. Despite their common etiology, DFTD and CTVT have evolved independently and have unique life histories and host adaptations. DFTD is a recently emerged aggressive facial tumor that is threatening the Tasmanian devil with extinction. CTVT is a sexually transmitted tumor of dogs that has a worldwide distribution and that probably arose thousands of years ago. By contrasting the biology, molecular genetics and immunology of these two unusual cancers, I highlight the common and unique features of clonally transmissible cancers, and discuss the implications of clonally transmissible cancers for host-pathogen evolution. [ABSTRACT FROM AUTHOR]

Canine transmissible venereal tumor (CTVT) is an excellent model for investigating the interaction between host immunity and tumor growth. Although CTVT is an allograft, initially the host immune system is unable to destroy the tumor cells, and the tumor grows progressively for about 4–6 months (P phase). After a short stable phase, the tumor undergoes regression (R phase). In this study, CTVT inoculation significantly reduced the proportion of B lymphocytes among all peripheral blood lymphocytes (PBL), but the proportion of B lymphocytes returned to normal after complete removal of CTVT. Following CTVT inoculation, immunoglobulin concentrations decreased gradually, coincident with B lymphocyte decline. Furthermore, CTVT secreted a soluble, heat- and protease K-sensitive cytotoxic molecule(s) that destroyed peripheral blood B lymphocytes (PBBL) but spared other types of immune cells regardless of whether mitogens, such as IL-2 or Con A, were present. The decrease in the proportion and viability of PBBL was caused by a cytotoxic molecule(s) that induced apoptosis. The molecular weight of the CTVT-derived cytotoxic molecule(s) was 30–100 kDa. Human, domestic cat, horse and mouse B cells were also sensitive to the substance. [Copyright &y& Elsevier]

Abstract Background Chemokines play multiple roles in the development and progression in a variety of tumors. Chemokine (C-X-C motif) ligand 7 (CXCL7) has been found associated with pro-inflammatory responses, but its role in cancer growth remains unclear. Our previous study showed that R phase tumor infiltrating lymphocytes (TILs) produced large amounts of interleukin (IL)-6 which antagonized transforming growth factor (TGF)-β derived from CTVT to diminish the immune-suppressive microenvironment. Now we intend to determine the expression pattern of CXCL7 and the role of IL-6/TGF-β in CXCL7 induction during spontaneous progressive (P) and regressive (R) phases in canine transmissible venereal tumor (CTVT). Results We have demonstrated that CXCL7 expressed at high level in P phase and down-regulated in R phase by western blot and real-time PCR. This suggested that CXCL7 expression was negatively correlated with the tumor growth. Co-culturing TILs with CTVT cells was found to reduce CXCL7 expression, while adding IL-6 blocking antibody reversed it. Moreover, in P phase CTVT, while IL-1β and TGF-β had no obvious effect on CXCL7 expression, IL-6 was found significantly to reduce CXCL7 expression in a dose-dependent manner. The mRNA expression results of CXCL7 receptor, CXCR2, further confirmed the effects of IL-6 concentration on the CXCL7 expression. Conclusion CXCL7 overexpression might be associated with the progressive growth of CTVT. The results shown here also suggest the role of CXCL7 in cancer development and the potential as the anti-cancer therapeutic target.

The devil facial tumor disease (DFTD) is a contagious cancer that has recently emerged among tasmanian devils, rapidly decimating the population. We have recently discovered that DFTD cells lose expression of MHC molecules on the cell surface, explaining how this tumor avoids recognition by host CD8+T cells. [ABSTRACT FROM AUTHOR]

Background: Interferons (IFNs), signaling proteins produced by host cells, are secreted in response to pathogen activity as well as to tumor cells, and display antiviral, antiproliferative, and immunomodulatory effects. Recombinant feline interferon omega (rFeIFN-ω) has in vitro growth inhibition activities on various canine and feline tumor cell lines. Canine transmissible venereal tumor (CTVT) is used as an animal model for immunotherapy due to its specific growth phase. Previous studies have usually focused on the interaction between tumor infiltrating lymphocytes (TILs) and CTVT cells. However, the specific effects of rFeIFN-ω on CTVT cells remains poorly defined. Aims: The aims of this study, therefore, were to evaluate the in vitro effect of rFeIFN-ω on primary CTVT cells and to study the mRNA expression of apoptotic genes and drug resistance genes. Materials and Methods: Purified CTVT cells were treated with various concentrations of rFeIFN-ω and the viability of the cultured cells was ascertained at 24, 48, and 72 h post treatment (hpt) and a dose-response curve plotted. The mRNA expression of apoptotic ( BAX and BCL-2 ) and drug resistance ( ABCB1 and ABCG2 ) genes was performed by reverse transcription quantitative real-time PCR at 72 hpt. Results: rFeIFN-ω displayed an effect against CTVT cell viability, which decreasing viability in a dose-dependent manner within 72 hpt. The relative mRNA expression of BCL-2 was upregulated only at a rFeIFN-ω concentration of 10 4 IU/100 μl. However, higher concentrations of rFeIFN-ω gave a higher level of relative mRNA expression of ABCB1 transporter gene. Conclusion: This study provided the information of in vitro effect of rFeIFN-ω on CTVT cell viability in a dose dependent manner, as well as, the alteration of BCL-2 and ABCB1 gene expression after treatment. These results encourage future in vivo studies to evaluate the potential efficacy of this treatment in CTVT cases.

ABSTRACT: Canine transmissible venereal tumor (CTVT) is a naturally occurring contagious round-cell neoplasia, with poorly understood origin and transmission. This study aims to further investigate the tumor nature through immunohistochemistry, lectin histochemistry and transmission electron microscopy (TEM) analysis, and to provide support for diagnostic and differential diagnoses of CTVT. Immunohistochemistry was performed in 10 genital and six exclusively extragenital tumors, which were previously diagnosed by citology and histopathology. CTVT samples were incubated with biotinylated antibodies to specific membrane and cytoplasmic antigens (anti-lysozyme, anti-macrophage, anti-vimentin, anti-CD18, monoclonal anti-CD117, monoclonal anti-CD3, polyclonal anti-CD117, polyclonal CD3 and anti-CD79a), followed by the avidin-biotin-peroxidase complex technique. The lectins Con A, DBA, SBA, PNA, UEA-1, WGA, sWGA, GSL, JSA, PSA, PHA-L, PHA-E and RCA were additionally tested in four genital CTVTs and TEM was performed in eight genital tumors. The anti-vimentin antibody revealed strong immunoreactivity to neoplastic cells in all the assessed samples (16/16). The polyclonal anti-CD3 antibodies showed moderate to strong immunoreactivity in fourteen (14/16) and the polyclonal anti-CD117 in fifteen cases (15/16). There was no immunoreactivity to anti-lysozyme, anti-macrophage, anti-CD18, monoclonal anti-CD117, monoclonal anti-CD3 and anti-CD79a antibodies. At lectin histochemistry, it was observed strong staining of tumor cells to Con-A, PHA-L and RCA. There was no histopathological and immunoreactivity differences between genital and extragenital CTVTs. These findings do not support the hypothesis of histiocytic origin of CTVT. In contrast, the lectin histochemical results were similar to cells from lymphoid/myeloid origin.