Upregulated MYC expression and p53 mutations may contribute to the oncogenesis of canine Meibomian gland carcinomas

Sebaceous carcinomas of the human ocular adnexa commonly exhibit pagetoid spread, mutations in tumor-suppressor genes, and protooncogene copy number gain. Sebaceous carcinomas are rarely reported in other species, and while the Meibomian gland (MG) represents the most common ocular adnexal structure of the canine eyelid to develop neoplasia, most are clinically and histologically benign. The objective of this study was to compare molecular features of canine MG carcinomas and adenomas. Two retrospectively identified MG carcinomas were subject to immunohistochemistry and qPCR. When compared with normal glands, MYC was upregulated in benign and malignant MG neoplasms. Aberrant p53 expression was restricted to the nuclei of intraepithelial neoplastic cells in MG carcinomas. Adipophilin expression was diminished in MG neoplasms compared with the normal MG. Our findings, if confirmed in a larger cohort of cases, could suggest that MG oncogenesis in a dog may exhibit similar molecular features as their human counterparts.

c-FOS drives reversible basal to squamous cell carcinoma transition

While squamous transdifferentiation within subpopulations of adenocarcinomas represents an important drug resistance problem, its underlying mechanism remains poorly understood. Here, using surface markers of resistant basal cell carcinomas (BCCs) and patient single-cell and bulk transcriptomic data, we uncover the dynamic roadmap of basal to squamous cell carcinoma transition (BST). Experimentally induced BST identifies activator protein 1 (AP-1) family members in regulating tumor plasticity, and we show that c-FOS plays a central role in BST by regulating the accessibility of distinct AP-1 regulatory elements. Remarkably, despite prominent changes in cell morphology and BST marker expression, we show using inducible model systems that c-FOS-mediated BST demonstrates reversibility. Blocking EGFR pathway activation after c-FOS induction partially reverts BST in vitro and prevents BST features in both mouse models and human tumors. Thus, by identifying the molecular basis of BST, our work reveals a therapeutic opportunity targeting plasticity as a mechanism of tumor resistance.

Cellular and biological evaluation and diagnostic immunohistochemistry of cytokeratin 15/19 expression in distinguishing cutaneous basal cell carcinoma

Recent studies have investigated the expression of proliferative markers, but little is known about the expression of cytokeratin 15 and 19 in different histological subtypes of basal cell carcinoma (BCC). We conducted cellular, biological, clinicopathological and immunohistochemical analysis on the manifestations of 8 BCC by hematoxylin and eosin stain (H&E) staining and immunohistochemistry and reviewed relevant literature. Microscopically, the tumor cells were multiple remarkable foci of epidermolytic hyperkeratosis with large pleomorphic nuclei and scant cytoplasm together with peripheral palisading and forming solid nests. Furthermore, the most tumors were composed of highly cellular areas with a homogenous population of round, ovoid and spindle cells, hyperchromatic nuclei, high cellular pleomorphism, high mitotic index and various morphologic patterns. Moreover, the tumors displayed an invasive growth, with positive expression of Cytokeratin 19 (CK19) and negative expression of CK15. Our study revealed that the expression of CK19 was associated with progression and invasion in cases with BCC and immunohistochemistry is indispensable in distinguishing this tumor from other types of cutaneous carcinoma. To our best knowledge, it may be a considerable biomarker to assess invasiveness of cutaneous-surface BCC and to guide clinical management of such tumors.

Nucleomorphometric analysis of feline basal cell carcinomas

Twenty-four feline spontaneous basal cell carcinomas (BCCs) were analyzed by computerized nuclear morphometry. The study included 15 non-recurrent and 9 recurrent tumours. In each case, the nuclei of at least 100 neoplastic cells were measured, and the mean nuclear area (MNA), mean nuclear perimeter (MNP) and mean nuclear diameter (MND) were calculated. The analysis of data of the non-recurrent BCCs and the recurrent tumours revealed statistically significant differences between those groups (p<0.001) as well as between infiltrative and clear types of BCCs (p<0.05). The results indicate that nuclear morphometry is able to predict recurrent tumour growth and helps to differentiate histological subtypes of BCCs in cats.

Follicular stem cell carcinoma: histologic, immunohistochemical, ultrastructural, and clinical characterization in 30 dogs

Diagnostic records of 30 primary and one metastatic follicular stem cell carcinomas in 30 dogs were reviewed. Neoplastic cells had a clear cytoplasm and formed lobules and nests surrounded by a basement membrane. Trichoepitheliomatous and apocrine differentiations were noted in 22 of 30 (73%) and 21 of 30 (70%) primary tumors, respectively. Glycogen was present in 20 of 20 (100%) tumors tested, suggesting tricholemmal differentiation. Antibodies against AE1/AE3 cytokeratin, vimentin, and melanA/MART1 stained 29 of 30 (97%), 29 of 30 (97%), and 12 of 27 (44%) primary tumors, respectively. Small amounts of melanin were identified in 14 primary tumors, either on the hematoxylin and eosin-stained section (n = 6), or on the Fontana-stained section (n = 8 of 14). Ultrastructural features of neoplastic cells included cell junction complexes, swollen mitochondria, neuroendocrine-like granules, and intracytoplasmic non-membrane-bound accumulation of proteinaceous material. Features of this neoplasm are consistent with a follicular stem cell origin. Follow-up information was available for eight dogs. Metastases developed in the draining lymph node at the time of excision of the primary tumor (n = 1) or subsequently (n = 3).

Differentiated basal cell carcinoma in a Cape clawless otter (Aonyx capensis)

Basal cell carcinoma with folliculoapocrine differentiation was diagnosed in a male Cape clawless otter (Aonyx capensis) aged >8 years. A tumour mass in the left submandibular region was removed surgically, but another tumour subsequently appeared on the left cheek. In addition, necropsy revealed a subcutaneous tumour mass at the excision site. Histologically, the tumours consisted of lobules or islands of basaloid cells, frequently with central keratinization and tubular structures. The presence of isthmic keratinization and apocrine differentiation was confirmed by immunolabelling for cytokeratins, and a few cytokeratin-positive tumour cells were found in a submandibular lymph node. The neoplasm, characterized by its metachronous and recurrent nature, metastasis to the local lymph node and amyloidosis, closely resembled human differentiated basal cell carcinoma, both clinically and pathologically.

Assessment of cytological criteria for diagnosing basal cell tumours in the dog and cat

A retrospective study was undertaken in which cytological features of basal cell tumours from 18 dogs and 12 cats were examined. Fine-needle aspiration biopsy was performed for cytological examination and diagnosis was confirmed on histopathological examination of excised tumour specimens. Cytological smears were analysed for occurrence of cystic areas, as well as frequencies of squamous cells, fibrocytes, fibroblasts, neutrophils, lymphocytes, mast cells, melanocytes and basal cells. Basal cell aggregates were examined for indicators of malignancy, evidence of basaloid cell structure, well defined cellular borders and cell aggregation patterns. Cellularity and quality of smears was moderate to good, although, in six aspirates, cellularity was poor due to a high amount of degenerate material within the tumours. Fifteen of the smears revealed between one and three nuclear criteria of malignancy. However, despite the less well differentiated appearance of basal cells that was sometimes seen, the tumours were considered benign based on histopathological examination. Basal cell tumours are therefore likely to be underdiagnosed on cytological examination due to non-specific features. The occurrence of other cell populations and lack of cells with basaloid structures and linear aggregation patterns might further confuse the tumour diagnosis. The authors conclude that the cytological diagnosis of basal cell tumours can be based on the criteria described in the present study.

A cytokeratin profile of canine epithelial skin tumours

The reactions of a number of epithelial skin tumours in dogs to a panel of monoclonal antibodies against different human cytokeratins (CKs) were examined immunohistochemically, the purpose being to detect a specific CK profile. CK 6 was present in all epithelial skin tumours with the exception of pilomatrixoma. CK 14 was found in basal cell-derived neoplasias and in sebaceous and perianal gland tumours. CK 10/11 was restricted to spinous cell-derived tumours and CK 8/18 was limited to sweat gland tumours.

Absence of p21 WAF1 and p27 kip1 gene mutations in various feline tumours

The coding regions of tumour suppressor and cell cycle regulatory genes p21 WAF1 and p27 Kip1 were investigated in 101 feline tumours of various types. No damaging mutations were present in the analysed areas of the genes.

Measurement of telomerase activity in dog tumors

Telomeres are specific structures present at the end of liner chromosomes. DNA polymerase can not synthesize the end of liner DNA and, as a result, the telomeres become progressively shortened by successive cell divisions. To overcome the end replication problem, telomerase adds new telomeric sequences to the end of chromosomal DNA. The enzyme activity is undetectable in most normal human adult somatic cells, in which shortening of the telomere is thought to limit the somatic-cell life span. In contrast to normal somatic cells, many human tumors possess telomerase activity. The present study looked at whether telomerase activity might serve as a marker for canine tumors. Telomerase activity was measured using the telomeric repeat amplification protocol assay. Normal dog somatic tissues showed little or no telomerase activity, while normal testis exhibited a high level of telomerase activity. We measured telomerase activity in tumor samples from 45 dogs; 21 mammary gland tumors, 16 tumors developed in the skin and oral cavity, 7 vascular tumors and 1 Sertoli cell tumor. Greater than 95% of the tumor samples contained telomerase activity (3-924 U/2 micrograms protein). The results obtained in this study indicated that telomerase should be a useful diagnostic marker for a variety of dog tumors, and it may serve as a target for antitumor chemotherapy.

Apoptosis and mitosis in tumours of the skin and subcutaneous tissues of the dog

The presence of apoptotic cell death was evaluated in routinely processed tissue samples of 39 neoplasms of the skin and subcutaneous tissues of the dog using the method of terminal deoxynucleotidyl transferase (T d T) mediated deoxyuridine-5'-triphosphate (d UTP)-biotin nick end labelling (TUNEL). The degree of apoptosis was related to the frequency of mitosis, an index of cell proliferation. The correlation between the apoptotic index (AI), the percentage of positive cells after randomly enumerating 1000 cells and the mitotic count (MC), the number of mitotic figures in 10 fields at a magnification of 400 times was assessed by the Spearman non-parametric correlation test. TUNEL signals were observed in all types of tumours as brown products detected in non-pyknotic nuclei, in non-identifiable rounded structures (so-called apoptotic bodies) and occasionally in the cytoplasm, either singly or in combination. An inverse relationship between AI and MC was observed in benign tumours, while no correlation was found between AI and MC in either malignant or locally invasive tumours. Among benign tumours, intracutaneous cornifying epithelioma, fibroma, haemangioma and Schwannoma had high AI and low MC, while histiocytomas had low AI and high MC and pilomatrixomas low AI and MC. All malignant tumours had low AI and high MC, except for fibrosarcomas, which had high AI and MC. Finally, higher heterogeneity was observed among locally invasive tumours, as they had high AI and low MC (squamous cell carcinomas), and low AI with either low MC (haemangiopericytomas) or high MC (basal cell tumours). The classification of the tumours according to their AI (>15.8% high and <15.8% low) and MC (>9 high, <9 low) did not reflect the clinical behaviour of some tumour types.

Reciprocal translocation in a case of canine basal cell carcinoma

A case of basal cell carcinoma in a 10-year-old spaniel dog was analysed cytogenetically. A reciprocal translocation t(10;35) was detectable.

Basal cell carcinoma in a blue-fronted amazon parrot (Amazona aestiva)

Tumors of the integumentary system are relatively common in companion birds. Dermal tumors in pet birds can be epithelial, mesenchymal, or vascular in origin. Basal cell carcinomas appear to be extremely rare in birds. An adult female blue-fronted Amazon parrot was examined because it exhibited bilateral cervical masses that extended from the base of the skull to the ingluvial region. The tumors were removed by surgical excision. Microscopic examination of the masses revealed neoplastic epithelial cells that extended to all borders of the sections; scattered vessels with neoplastic cells within their lumens were also found. The histopathologic diagnosis was basal cell carcinoma. Six weeks postoperatively, the masses recurred and the bird was euthanatized. This report suggests that basal cell carcinomas should be considered as a differential for avian dermal tumors. This neoplastic condition can be aggressive and has the potential to metastasize.

Expression of proliferating cell nuclear antigen in basal cell carcinomas and in squamous cell carcinomas of canine skin: correlation with mitotic index and histological features

In this study we evaluated the behaviour of proliferating cell nuclear antigen labelling index (PCNA-LI), mitotic index (MI) and histological features in ten basal cell carcinomas (BCC) and ten squamous cell carcinomas (SCC) of canine skin. PCNA-LI ranged from 2.1% to 4.8% in SCC and from 0.1% to 2.0% in BCC samples. A significant statistical correlation, between PCNA-LI and MI could be demonstrated only in SCC, but not in BCC samples. Furthermore, PCNA-LI was also significantly and consistently greater in the three BCC of solid type and in poorly differentiated SCC. PCNA-LI may provide additional criterion in evaluating the intrinsic malignancy and growth potential of the above tumours.

Basal cell tumor in a Japanese macaque (Macaca fuscata)

A rare case of basal cell tumor of the skin in a wild-caught female Japanese macaque (Macaca fuscata) was studied. Tumor growth, which was composed of cells resembling basal cells, was observed in the dermis and subcutis and showed a mixture of ribbon, solid, glandular, and cystic patterns. The tumor was separated from surrounding normal tissue by a compressed zone of fibrous connective tissue. The nuclei were round and hyperchromatic and possessed a single centrally located nucleolus. Mitotic figures were common. Immunohistochemically, a positive reaction for epithelial membrane antigen, keratin, and cytokeratin AE3 was evident. Electron microscopic examination revealed a small number of tonofilaments in the cytoplasm.

Distribution of hypoxia and proliferation associated markers in spontaneous canine tumors

The therapeutic response of malignant tumors depends on a number of factors associated with tumor microenvironments including the possibility that these microenvironments change during treatment. Two factors, tumor hypoxia and cell proliferation, have been examined in spontaneous canine tumors undergoing multifraction radiation therapy. The approach utilizes immunohistochemical analyses of hypoxia (CCI-103F) and proliferation associated (PCNA) antigens in biopsy samples taken before and after 5 daily fractions of 3 Gy (total dose 15 Gy). The tissue samples were formalin-fixed and paraffin-embedded for the immunohistochemical study. Immunostaining of the sections for PCNA and hypoxia marker reveals little or no overlap when the analysis is made prior to irradiation. An increased degree of overlap seems to occur after 15 Gy but the situation is complicated by a change towards more diffuse PCNA immunostaining in the cells of the irradiated tissues.

Nucleolar size and mitotic index in basal cell carcinomas (BCC) and squamous cell carcinomas (SCC) of canine skin

Nine squamous cell carcinomas (SCC) and ten basal cell carcinomas (BCC) of the dog's skin were retrospectively evaluated from the point of view of both their nucleolar size and their mitotic index. With the exception of one, all SCC samples under investigation were non-metastasizing. Mean nucleolar area/cell ranged from 4.36 to 9.87 microns 2 in SCC, and from 1.06 to 2.59 microns 2 in BCC samples. A significant statistical correlation could be demonstrated between cell nucleolar area and mitotic index in SCC samples.

Cutaneous neoplasia in 340 cats

A total of 340 cases of cutaneous neoplasia were diagnosed in 340 of 3,564 cats that were examined by biopsy or necropsy during a 41-month period from January 1, 1986 through May 31, 1989. Eighteen types of tumor occurred, but four types comprised 77% of the cases. These were basal cell tumor, 89 cases (26%, mean age 10.3); mast cell tumor, 72 cases (21%, mean age 8.6); squamous cell carcinoma, 52 cases (15%, mean age 11.6); and fibrosarcoma, 50 cases (15%, mean age 10.2). For each of these four types of tumors, peak number of cases occurred in cats older than 10 years. Mast cell tumor was the only tumor diagnosed in cats younger than 1 year. The head was the most common site for basal cell tumors, mast cell tumors, and squamous cell carcinomas. The legs were the most common location of fibrosarcomas. Siamese cats had approximately three times as many mast cell tumors as statistically expected, but only one-fourth as many squamous cell carcinomas. Breed predilection for other skin tumors was not apparent. Sex predilection was not detected for any skin tumor.

Ultraviolet radiation-induced skin tumors in a South American opossum (Monodelphis domestica)

A total of 19 male and 21 female South American opossums (Monodelphis domestica) were exposed to 250 J/m2 ultraviolet radiation from FS-40 sunlamps (280-400 nm) three times weekly for 70 weeks. The backs of the opossums were shaved as necessary to remove hair. In order to prevent photoreactivation of ultraviolet radiation-induced pyrimidine dimers by the light-dependent photolyase enzyme of the opossum, ultraviolet radiation-exposed opossums were housed under red lights (600-800 nm). The opossum photolyase requires light in the 320-450 nm range for its activity. Twenty-nine control opossums (14 males and 15 females) were irradiated by fluorescent lights with emission spectra primarily in the visible light range (320-700 nm); these control opossums were also housed under red lights, and their backs were also shaved to remove hair. No skin tumors were observed in control opossums, while ultraviolet radiation-exposed opossums developed a variety of hyperplastic and neoplastic skin lesions on the backs and on a single ear. Hyperplastic lesions included foci of epithelial hyperplasia, dermal fibroplasia, and focal proliferation of dermal melanocytes. A total of 20 ultraviolet radiation-exposed opossums (50%) developed skin tumors, and 13 opossums (32.5%) had more than a single tumor. Epithelial tumors included 25 papillomas, four keratoacanthomas, seven carcinomas in situ, three microinvasive squamous cell carcinomas, two invasive squamous cell carcinomas, and a single basal cell tumor. Ten dermal spindle cell tumors also occurred; most of these appeared to be fibrosarcomas. Two benign melanomas and one malignant melanoma were observed.

Neoplasia involving the middle ear cavity of dogs

Eleven cases of neoplasia which involved the middle ear cavity of dogs are recorded. Eight of the tumours originated in the external ear canal and comprised four adnexal tumours, one squamous papilloma and three adenocarcinomas of the ceruminous glands. Papillary adenomas were recognised within the middle ear cavity of two dogs. In one animal the precise origin of an anaplastic carcinoma involving the middle ear could not be determined. Only five of the tumours were amendable to surgical excision and four dogs survived for more than eight months after surgery.

Cartilaginous metaplasia associated with a basal cell tumour in a dog

Locally extensive dermal cartilaginous metaplasia was seen in association with a pigmented basal cell tumour in an aged, spayed Basenji dog. Six months after surgical excision, the animal remains healthy with no recurrence of the neoplasm.

Cutaneous neoplasms in dogs associated with canine oral papillomavirus vaccine

A spectrum of proliferative cutaneous lesions occurred in 12 dogs at the injection site of live canine oral papillomavirus (COP) vaccine, suggesting a viral etiology for the masses. Lesions included epidermal hyperplasia, epidermal cysts, squamous papilloma, basal cell epithelioma, and squamous cell carcinoma. Peroxidase-antiperoxidase staining of tumor sections revealed nuclei which stained for group-specific papillomavirus antigen in five of 12 masses. Electron microscopic examination of tumor sections did not reveal virions. In transmission studies, macerated tumor tissue did not produce oral papillomas on the scarified mucosa of puppies; this procedure did protect the puppies from development of lesions when challenged with infectious papilloma material. These findings are evidence that COP can induce hyperplastic and neoplastic lesions in sites other than oral, pharyngeal, and ocular mucosa.

Skin neoplasms of dogs in Sydney

In a survey of dogs in Sydney, mastocytomas (16.1%) and histiocytomas (14.0%) were the most common in a total of 1,000 skin neoplasms. The basal cell and appendage group provided 25.5% of the neoplasms. The prevalence of the various neoplasms, the age of affected dogs, the proportion in the sexes, the common sites of occurrence and prevalence in the different breeds were broadly similar to findings in surveys in other countries, except that in the Syndeny dogs there was a greater prevalence of histiocytomas and haemangiopericytomas, a more common occurrence of histiocytomas in mature dogs, an occurrence of histiocytomas in similar numbers on the head, trunk and limbs, and a remarkably common development of squamous cell carcinomas in Dalmatians.

Classification and behaviour after surgery of canine 'epulides'

Seventy-five surgically excised canine gum neoplasms, which had previously been diagnosed as epulis or ameloblastoma, were reclassified on the basis of their presumed tissue of origin. They included 42 tumours of fibroblastic origin, which contained small foci of odontogenic epithelium and were classified as peripheral odontogenic fibroma, whilst 31 epithelial tumours were classified as basal cell carcinomas arising from the gum epithelium. Two epithelial tumours which apparently arose within the bone of the mandible and were not connected with the surface mucosa were classified as ameloblastomas. Follow-up studies after surgery revealed a recurrence rate of 17 per cent for the odontogenic fibromas and 50 per cent for basal cell carcinomas. Neither of the ameloblastomas, which were initially treated by radical excision, recurred locally and no metastases were detected from any of these tumours.

Equine basal cell tumors

Basal cell tumors from 11 horses were examined histologically. Distinct patterns identified in the order of frequency are adenoid (six), solid (three), and medusoid (two). A minor component of most of these neoplasms was a ribbon pattern and cystic spaces. Hyalinized connective tissue and clear cells reminiscent of hair follicle glassy membranes and outer root sheath were present in a solid and the medusoid tumors. Heavy melanin pigmentation was present in one solid basal cell tumor. In eight cases for which information was available, the tumors had not recurred 3 to 8 years after excision.

Multicentric basal cell tumors in a cat

Four basal cell tumors were diagnosed in an adult spayed female domestic longhair cat. Surgical excision was curative. Basal cell tumors in cats usually are solitary, slow growing, benign epithelial neoplasms. The multicentric nature of these neoplasms in this patient was uncharacteristic of typical basal cell tumors in cats.

Feline basal cell tumors: a review of 124 cases

Basal cell tumors from 124 cats of six breeds which represented 4.2% of feline neoplasms and 10.9% of feline cutaneous neoplasms are characterized. The mean age of cats affected was 9.6 years, and an increased risk was correlated positively with increasing age (rxy = +0.85). Males, females, and castrates were affected equally. Long-haired breeds were at higher risk (p less than 0.01) for development of basal cell tumors which had two major histologic types--solid and cystic. No site predilection was apparent.

Granular basal cell tumors in the skin of three dogs: a distinct histopathologic entity

Granular cell variants of cutaneous basal cell tumors from three dogs are described. These tumors resemble a granular cell variant of basal cell tumor (carcinoma) in man. The tumors are characterized by classical basal cells as well as granular cells with numerous cytoplasmic granules. These granules are cytoplasmic vacuoles 0.3 micrometer to 1.5 micrometer that seem to be secondary lysosomes; they usually contain many small (42 nm), membrane-bound vesicles. No natural, non-neoplastic counterpart of these granular cells is known to exist in the skin, and the significance of the production and accumulation of the small vesicles is not known. The cytoplasmic granules, and their contents, resemble the granules of granular cell "myoblastoma" although granular basal cells are of epithelial origin.

Basal cell tumors in dogs

In a review of neoplasm registry records at Kansas State University (1961 through 1971), 140 basal cell tumors were reported in 32 breeds of dogs, representing 4.3% of 3,230 neoplasms recorded. Mean age of the affected dogs was 6.4 years. The tumors were removed surgically for biopsy in all dogs, 10 of which then had recurrences without metastasis, and required further surgery. The head, neck, and shoulder were a principal site (61%) of basal cell tumors in the dog.

Tumours of the skin

Tumours occur more frequently in the skin than in any other part of the body. Epithelial tumours are described under the following headings: basal cell tumour, squamous cell carcinoma, papilloma, sebaceous gland tumour, tumour of hepatoid glands, sweat gland tumour, mixed tumour of apocrine sweat glands, carcinoma of apocrine sweat glands, tumour of hair follicle, and intracutaneous cornifying epithelioma. Tumours of the melanogenic system are divided into benign melanoma and malignant melanoma, the latter being subdivided into the following types: epithelioid, spindle cell, epithelioid and spindle cell, dendritic, and whorled.

Basal cell tumour of third eyelid in a horse

Images

[Submicroscopic studies on basaloma in the dog]

Six basal cell tumors of dogs were studied electron microscopically. The ultrastructure of different types of basal cell tumor differs as to the number of tonofibrils, the finger-like cytoplasmic extensions, the width of the intercellular spaces, and the hyaloplasma. Hemidesmosomes were found in all tumors. One basal cell tumor contained single cells resembling sebaceous cells which indicates differentiation of basal cells into sebaceous glands. Furthermore, there are ultrastructural differences between the cells of the stratum germinativum and the basal cell tumor.