Immunohistochemical Expression of Human Epidermal Growth Factor Receptor 2 and Ki67 in Apocrine Gland Anal Sac Adenocarcinoma.

Apocrine gland anal sac adenocarcinoma is an aggressive neoplasm, and surgery remains the treatment of choice, although it is controversial in advanced cases. The prognostic factors are not well established. Human Epidermal Growth Factor Receptor 2 (HER2) is a membrane protein related to tumorigenesis, whereas Ki67 is a nuclear protein related to cell proliferation. Both are potential prognostic markers and therapeutic targets. This study aimed to evaluate the expression of HER2 and Ki67 markers in canine apocrine gland anal sac adenocarcinoma. The tumor samples were divided into four groups: largest tumor diameter less than 2.5 cm, largest tumor diameter greater than 2.5 cm, metastatic lymph nodes, and control group of non-neoplastic anal sacs. Each contained 10 samples. Immunohistochemistry was performed to verify the expression of HER2 and Ki67 markers. Positive HER2 staining was observed in 45% of the neoplastic cases and negative HER2 staining in 100% of the control group. The Ki67 expression had a median of 25% in all groups, except for the control group, which had a median of 8%. The HER2 and Ki67 expression was present in apocrine gland anal sac adenocarcinoma, making them potential therapeutic targets. However, it was not possible to determine the clinical value of either marker.

Gene expression of prostaglandin EP4 receptor in three canine carcinomas.

BACKGROUND: Chronic inflammation mediated by the cyclooxygenase enzymes, specifically their product prostaglandin E2 (PGE2), can result in the development of cancer. PGE2 promotes cell proliferation, apoptosis, and angiogenesis through interaction with its specific receptors (EP1 receptor - EP4 receptor [EP1R-EP4R]). In multiple human cancers, the expression of EP4R is associated with the development of malignancy and a poor prognosis. The expression of EP4R has not yet been evaluated in canine tumors. The aim of this study was to characterize the mRNA gene expression of EP4R (ptger4) in canine squamous cell carcinoma (SCC), apocrine gland anal sac adenocarcinoma (AGASACA), and transitional cell carcinoma (TCC). Archived tumor samples of canine cutaneous SCC (n = 9), AGASACA (n = 9), and TCC (n = 9), and matched archived normal tissue controls were evaluated for mRNA expression of canine EP4R using RNA in situ hybridization (RNAscope®). Quantification of RNAscope® signals in tissue sections was completed with an advanced digital pathology image analysis system (HALO). Data was expressed as copy number, H-index, and percent tumor cell expression of EP4R. RESULTS: In all canine SCC, AGASACA, and TCC samples evaluated, strong universal positive expression of EP4R was identified. For SCC and AGASACA, mRNA EP4R expression was statistically higher than that of their respective normal tissues. The TCC tissues displayed significantly less mRNA EP4R expression when compared to normal bladder mucosa. CONCLUSIONS: These results confirm the mRNA expression of canine EP4R in all tumor types evaluated, with SCC and AGASACA displaying the highest expression, and TCC displaying the lowest expression. This study also represents the first reported veterinary evaluation of EP4R expression using the novel in situ hybridization technique, RNAscope®.

Detection of human epidermal growth factor receptor 2 overexpression in canine anal sac gland carcinoma.

Canine anal sac gland carcinoma (ASGC) frequently occurs in the apocrine glands of the canine anal sac and shows aggressive biological behavior. The expression of human epidermal growth factor receptor 2 (HER2) has been reported in various human and canine tumors. HER2 is a promising therapeutic target of these tumors, and HER2-targeted drugs, such as trastuzumab and lapatinib, have improved the outcome of these patients. In this study, HER2 expression in ASGC was evaluated to investigate its potential as a therapeutic target for canine ASGC. HER2 mRNA expression in surgically resected ASGC tissues was significantly higher than that in normal anal sac tissue. To evaluate the expression of HER2 protein, paraffin-embedded ASGC tissues were immunohistochemically evaluated. Strong and broad staining of HER2 was detected in ASGC tissues, while HER2 was weakly to moderately stained in normal anal sac apocrine glands and squamous epithelia. The degree of HER2 expression in ASGC tissues was scored based on its intensity and positivity (score: 0-3+). Scoring of HER2 expression revealed 6 samples (24%) scored 3+, 14 (56%) scored 2+, and 5 (20%) scored 1+, with no samples scoring 0. In all, 80% of canine ASGC tissues were positive for HER2 (scored ≥2+). Furthermore, putative HER2-overexpressed cells in ASGC were detected with trastuzumab by flow cytometry. These preliminary data may lead to further evaluation of the role of HER2 in canine ASGC as a mechanism of malignancy and as a therapeutic target for HER2-targeted therapy.

EGF Level in Hepatoid Gland Adenomas and Hepatoid Gland Epitheliomas in Dogs After Administering Tamoxifen.

BACKGROUND/AIM: Neoplastic lesions of perianal glands account for approximately 10% of all skin cancer cases in dogs. They occur in many dog breeds, usually in male animals aged over 6 years. Due to their hormone-dependency, tamoxifen can be used in antineoplastic treatment. The aim of the study was to measure epidermal growth factor (EGF) levels in the serum of dogs with perianal tumours after tamoxifen treatment and to use it as a prognostic factor for further treatment. MATERIALS AND METHODS: The study was performed on 19 male dogs aged between 6 and 14 years, diagnosed with neoplastic hyperplasia in the perianal region. The control group comprised 10 healthy dogs brought in for routine castration. The research material comprised blood drawn from the animals and tumour specimens for histopathology. The study group received 1-month treatment with tamoxifen. Blood serum was then tested for 17-ß oestradiol level, and for EGF level on the first day of the therapy and 6 months after treatment completion. RESULTS: Hepatoid gland adenomas were diagnosed in 10 cases, and hepatoid gland epitheliomas in nine cases. Elevated 17-ß oestradiol levels were observed in all dogs. On the first day of treatment with tamoxifen, the serum EGF levels in all study groups were higher than in the control group. At the 6-month follow-up, the EGF levels were significantly reduced in hepatoid gland adenoma cases compared to those taken on the first day of treatment of tamoxifen, while in animals with hepatoid gland epithelioma, it was greatly increased and was correlated with relapse. CONCLUSION: Perianal gland tumours are characterised by EGF overexpression, which can be helpful in early-stage prognosis and treatment. An increase in EGF levels 6 months after tamoxifen therapy correlates with disease progression and may be a useful prognostic factor.

Diagnostic and prognostic value of cellular proliferation assessment with Ki-67 protein in dogs suffering from benign and malignant perianal tumors.

In the perianal region of carnivores, skin consists of modified sebaceous glands called perianal glands. Tumors originating from perianal glands are the third most frequent type of neoplasm in male dogs after neoplastic diseases of testes and skin. Ki-67 is a nuclear non-histone protein considered a proliferation marker in normal and neoplastic proliferating cells. Previous investigations revealed that Ki-67 expression may be used as a prognostic factor for breast cancer in humans. Thus, the aim of this study was to estimate the diagnostic and prognostic value of Ki-67 evaluation in dogs suffering from benign and malignant perianal tumors. The highest value of the Ki-67 index was obtained in the carcinoma group (18.50% ± 2.68), significantly higher compared to the values obtained in the control tissue (7.63% ± 2.12) and adenoma (7.33% ± 1.06; all P < 0.05). Statistically significant differences in the Ki-67 index were not found between the epithelioma group (11.95% ± 1.96) and all other groups (P < 0.05). This investigation on dogs with perianal gland tumors has shown significantly increased expression of Ki-67 antigen in carcinoma cells, while the expression of this protein was similar in the case of control tissues, adenoma and epithelioma. Thus, it may be postulated that Ki-67 evaluation in perianal gland tumors in dogs may serve as a useful marker possessing high diagnostic and prognostic value and enabling differentiation of malignant and benign tumors.

COX-2 expression in canine anal sac adenocarcinomas and in non-neoplastic canine anal sacs.

Anal sac adenocarcinoma (ASAC) is a clinically significant canine neoplasm characterized by early lymphatic invasion. Up-regulation of cyclooxygenase isoform 2 (COX-2) has been confirmed in several animal and human neoplastic tissues. The aim of the current study was primarily to evaluate COX-2 expression in canine ASAC and compare it to COX-2 expression in non-neoplastic canine anal sac tissue using immunohistochemistry with scoring for percentage positivity and intensity. Twenty-five ASAC samples and 22 normal anal sacs were available for evaluation. All canine ASAC samples and the normal anal sac tissues stained positively for COX-2. However, while normal anal sac tissue showed strong staining of the ductal epithelial cells, ASAC samples showed staining of the neoplastic glandular epithelial cells, with varying percentage positivity and intensity between ASAC samples. COX-2 immunoreactivity of ASAC samples was of low intensity in 52% and high in 12% of the cases; the remaining samples were of intermediate intensity. Seventy-six per cent of the ASAC had over 50% of the neoplastic glandular cells staining positive. These results confirm that COX-2 is expressed in the neoplastic glandular epithelial cells in canine ASAC and suggest a potential role for COX-2 inhibitors in the management of ASAC. Furthermore, the results indicate that COX-2 is expressed in ductal epithelial cells of the normal anal sac.

Immunohistochemical characterization of neuroendocrine differentiation of canine anal sac glandular tumours.

Histological features and expression of neuroendocrine markers were examined in 69 samples of canine anal sac glandular carcinomas (ASGCs). The tumours were classified into solid, rosette and tubular types and mixtures of these types. Tumour-associated death in dogs with solid tumours and mixed tumours with solid components was higher than in dogs with rosette and tubular type tumours. Chromogranin A immunoreactivity was observed in 28 of 69 samples (40.6%) irrespective of histological type and was localized to the marginal areas of the tumour nest and the basal areas of the tubular and rosette structures. Neuron-specific enolase immunoreactivity in neoplastic epithelial cells was observed in 32 cases (46.4%) and was less frequently observed in the tubular type (14.3%). Synaptophysin expression was present in 15.9% of cases and was least frequent in the tubular type. Twenty-one of the 69 samples expressed more than two neuroendocrine markers and were classified as carcinomas with neuroendocrine differentiation. There was no relationship between neuroendocrine differentiation and clinical outcome. These results suggest that some ASGCs have neuroendocrine differentiation regardless of histological pattern, but clinical outcome is more related to the histological pattern than to neuroendocrine differentiation.

Ki-67 labeling in canine perianal glands neoplasms: a novel approach for immunohistological diagnostic and prognostic.

BACKGROUND: The antibody Ki-67 is a reliable and easy tool to accurately assess the growth fraction of neoplasms in humans and animals, and it has been used to predict the clinical outcome. Therefore, the aim of the present study was to investigate the immunohistochemical expression pattern of Ki-67 in normal and neoplastic perianal glands of dogs to evaluate the possible use of this proliferation marker as an ancillary method of perianal tumor diagnosis. We studied 42 cases of perianal gland neoplasms including adenomas (n = 15), epitheliomas (n = 15), and carcinomas (n = 12). As controls, 13 tissue samples from normal perianal glands were used. A Ki-67 index was established by a computer-assisted image analysis and compared with manual counting. RESULTS: Out of the 42 cases of perianal gland neoplasms, 34 were from males and eight from females. Recurrence was reported in 14 cases, being higher (8/12) in carcinomas. Immunostaining for Ki-67 revealed that the carcinomas showed a higher proliferation rate (9.87%) compared to groups of epitheliomas (2.66%) and adenomas (0.36%). For adenomas and epitheliomas of the perianal glands the computer-assisted counting and the manual counting gave similar results; however, only the computer-assisted image analysis was efficient to predict the perianal gland carcinoma recurrence. CONCLUSION: Since there were significant differences in the number of Ki-67-positive nuclei, this marker proved to be effective in helping the classification of perianal gland neoplasms and to refine the diagnosis criteria, especially in those samples with high variation in morphology/area. Also, higher Ki-67 index is related to recurrence in cases of perianal gland carcinomas. Further, the computer-assisted image analysis proved to be a fast and reliable method to assess the Ki-67 index in perianal gland neoplasms.

Evaluation of expression and function of vascular endothelial growth factor receptor 2, platelet derived growth factor receptors-alpha and -beta, KIT, and RET in canine apocrine gland anal sac adenocarcinoma and thyroid carcinoma.

BACKGROUND: Toceranib phosphate (Palladia) has a reported objective response rate of 25% in both canine apocrine gland anal sac adenocarcinoma (AGASACA) and thyroid carcinoma (TC), with stable disease occurring in an additional 50-60% of dogs. The basis for the observed responses to toceranib is not known. The purpose of this study was to evaluate AGASACA and TC samples for the expression and activation of VEGFR2, PDGFRα, PDGFRß, KIT and RET to assess whether dysregulation of these receptor tyrosine kinases (RTKs) may contribute to the biologic activity of toceranib. RESULTS: mRNA for VEGFR2, PDGFRα/ß, KIT and RET was detected in all AGASACA samples. mRNA for VEGFR2, PDGFRα/ß, and KIT was detected in all TC samples, while mRNA for RET was amplified in 10/15 samples. No phosphorylation of VEGFR2, PDGFRα/ß, or KIT was observed on the arrays. However, phosphorylation of RET was detected in 54% of the primary AGASACA and 20% of TC. VEGFR2 was expressed in 19/24 primary and 6/10 metastatic AGASACA and 6/15 TC samples. KIT was present in 8/24 primary and 3/10 metastatic AGASACA and 9/15 TC samples. PDGFRα expression was noted in all tumor samples. In contrast PDGFRß expression was found in only a few tumor samples but was evident in the stroma of all tumor specimens. CONCLUSIONS: Known targets of toceranib are expressed in both AGASAC and TC. Given the observed expression of VEGFR and PDGFRα/ß and phosphorylation of RET, these RTKs merit investigation as to their roles in the biology of AGSACA and TC and their contribution to toceranib's activity.

Expression of claudin-5 in hepatoid gland biopsies.

Claudins are integral membrane proteins involved in the structure of the tight junctions found in epithelial and endothelial cells. This study evaluated the expression of claudin-5 in 67 hyperplastic and neoplastic lesions of canine hepatoid glands. These included normal hepatoid glands (n = 10), nodular hyperplasia (n = 10), adenomas (n = 12), epitheliomas (n = 15), differentiated carcinomas (n = 15) and anaplastic carcinomas (n = 15). There was intense lateral membrane expression of claudin-5 on epithelial cells from normal hepatoid glands, nodular hyperplasia and adenomas, but expression was weaker in hepatoid gland epitheliomas. Basal reserve cells from normal glands, nodular hyperplasia, adenomas and epitheliomas never expressed claudin-5. There was membrane-bound immunoreactivity for claudin-5 in selected areas of the epitheliomas where the cells exhibited typical hepatoid features. The weak expression of claudin-5 molecule in epitheliomas may nevertheless lead to cellular disorientation, detachment and invasion. Claudin-5 expression seemed to be helpful in distinguishing poorly differentiated carcinomas, differentiated carcinomas and epitheliomas of the hepatoid glands. Increased claudin-5 expression by invasive anaplastic carcinomas may facilitate invasion and metastasis through the activation of matrix metalloproteinases.

Expression of the claudin-4 molecule in benign and malignant canine hepatoid gland tumours.

Claudins are integral membrane proteins of the tight junction structures expressed by epithelial and endothelial cells. The present study has evaluated the expression of claudin-4 in 10 normal canine hepatoid glands and in 67 hepatoid glands with hyperplastic and neoplastic lesions. The lesions studied included normal hepatoid glands (n = 10), nodular hyperplasias (n = 10), adenomas (n = 12), epitheliomas (n = 15), differentiated carcinomas (n = 15) and anaplastic carcinomas (n = 15). There was an intensive expression of claudin-4 in normal canine hepatoid glands as well as in hyperplasias and adenomas. Claudin-4 was detected as a well-localised linear circumferential membranous staining pattern of epithelial cells (mature hepatoid cells) in normal hepatoid glands, perianal gland hyperplasias and adenomas. In nodular hyperplasia and adenoma, the reserve cells showed membrane positivity for the claudin-4 molecule. There was a weaker expression in hepatoid gland epitheliomas. In the epitheliomas, the basaloid reserve cells never expressed the claudin-4 molecule. The multiple small parts of epitheliomas in which the cells exhibited typical hepatoid features showed a well-localised linear circumferential membranous staining pattern for claudin-4. The numerical score for cellular expression of claudin-4 was higher in differentiated carcinomas than in epitheliomas, but moderately lower than in adenomas. The anaplastic, poorly differentiated hepatoid gland carcinomas showed an overexpression of claudin-4. These results suggest that low claudin-4 expression in epitheliomas is a molecular characteristic indicative of increasing cellular disorientation, detachment motility and invasion by tumour cells, and claudin-4 seems to be helpful in distinguishing undifferentiated carcinomas from differentiated carcinomas and epitheliomas of the hepatoid gland. In addition, claudin-4 can help distinguish epithelioma from differentiated carcinoma of the canine hepatoid gland.

Canine perianal gland carcinoma-associated antigens defined by monoclonal antibodies.

This study was conducted to distinguish canine perianal gland carcinomas from adenomas using monoclonal antibodies (MAbs). The adenomas generally retain the lobular architecture, but some may contain focal areas of cellular pleomorphism. These changes may suggest malignant transformation and have led to discordant interpretations. To address this histopathological confusion, two perianal gland carcinoma-associated antigens were defined by mouse MAbs 4A9 and 1A10. These MAbs, generated against a canine mammary carcinoma cell line, reacted strongly with perianal gland carcinoma in preliminary screening and therefore were selected for further investigation. Cellular expression of antigens was examined by indirect immunoperoxidase (IP) assay using MAbs 4A9 and 1A10 against formalin-fixed, paraffin-embedded sections of normal and tumor tissue. Of 25 perianal gland carcinomas, 4A9 antigen was expressed in 100% and 1A10 antigen in 84%. In contrast, perianal gland adenomas were negative for both antigens, and little or no reactivity was detected with normal perianal glands. With eight perianal gland tumors, diagnosis of carcinoma versus adenoma was histologically equivocal, while IP assays consistently revealed focal expression of the 4A9 and 1A10 antigens in these tumors, and the staining coincided with foci of anaplastic cells having a high mitotic index. This group of tumors was designated adenoma/carcinoma in situ. Results suggest that 4A9 and 1A10 antigens are markers of carcinoma and malignant transformation in canine perianal gland tumors, and can be very useful as diagnostic reagents where the identification of carcinoma versus adenoma requires additional clarification beyond routine histopathological examination.

Androgen receptor expression in normal, hyperplastic and neoplastic hepatoid glands in the dog.

Neoplasms of the perianal glands are common in the dog, particularly in the male. The occurrence of these tumours appears to be hormone related and castration, without excision of the tumour, has sometimes resulted in regression of the tumour. The aim of this study was to investigate the expression of androgen receptors (AR) in normal, hyperplastic and neoplastic hepatoid glands in the dog. Thirty-one samples of canine hepatoid gland tissues were investigated. The lesions, classified according to WHO criteria, were comprised of 19 hyperplastic tissues, 10 benign lesions (2 hepatoid gland epithelioma and 8 hepatoid adenomas), and 19 carcinomas. Five samples from normal hepatoid glands were also investigated. The AR expression was evaluated by immunohistochemistry using a streptavidin-biotin peroxidase method. The immunoexpression was scored by two pathologists as the percentage of positive nuclei. The intensity of staining was also considered. AR expression was detected in all normal and abnormal glands. However, in hyperplastic tissues the percentage of positive nuclei was significantly higher than in normal tissue and especially in reserve basaloid cells. A similar increase in the percent of positive nuclei was also observed in hepatoid epitheliomas, while in hepatoid adenoma the percent of AR-immunolabelling was only slightly increased compared to normal tissue. In hepatoid carcinomas the percent of AR-positive cells was similar to that observed in benign tumours. The grade of differentiation of hepatoid carcinomas did not affect AR expression. These results demonstrate that increased AR expression is maintained throughout perianal gland cancer progression and that hepatoid gland carcinomas still express AR. Although further studies may be required to evaluate the hormonal background of these diseases, dogs bearing those carcinomas might benefit from castration or anti hormonal therapy.

Immunohistochemical detection of growth hormone (GH) in canine hepatoid gland tumors.

The aim of this study was to detect immunohistochemically means growth hormone (GH) in 24 hepatoid gland adenomas and 5 hepatoid gland carcinomas and to compare the difference of immunoreactivity between types of tumors. The tumors were classified according to the WHO standards. Tissue sections which were prepared from formalin-fixed, paraffin wax-embedded tissues from 25 male and 4 female dogs were carried out immunostaining using polyclonal primary anti-hGH and EnVision method. Of 24 hepatoid gland adenomas (perianal gland adenomas) 23 (95.8%) were positive. All 5 hepatoid gland carcinomas (perianal gland carcinomas) were positive. No statistically significant differences in percentage of labelled cells between malignant and benign tumors were seen. The present demonstration of GH in hepatoid gland tumors adds new data on GH in extra-pituitary tissues and hormon-dependent tumors.

An improved system for quantifying AgNOR and PCNA in canine tumors.

BACKGROUND: Quantifying silver stained nucleolar organizer regions (AgNORs) and proliferation cell nuclear antigens (PCNA) are useful techniques to measure proliferative activity of tumor cells; however, the nonspecific deposition of stains and overlappings of AgNOR and PCNA counts between grades of tumors hamper their applications. MATERIALS AND METHODS: Fifty-two surgical specimens from dogs, including mast cell tumors, perianal gland tumors and hyperplasias, fibromas, fibrosarcomas, and normal tissues were studied. The 3 microns dewaxed sections of formalin-fixed tissues were stained to detect AgNORs by a modified inverted incubation technique in a newly developed silver staining device. Data were collected and analyzed using a high-resolution digital microscope camera and image analysis software. Sequential sections were also stained for PCNA using an immunohistochemical method. RESULTS: The improved system for quantifying AgNOR provided more accurate and non-overlapping mean AgNOR counts, which enable us to distinguish benign states from malignant changes. The mean AgNOR cut-off points that discriminated grade II or III mast cell tumors from grade I, perianal gland carcinomas from adenomas (or hyperplasia), fibrosarcomas from non-fibrosarcoma tissues, were 6.0, 14.1, 9.4, and 8.8 respectively. The mean AgNOR areas, relative AgNOR areas, and PCNA positive rates of some malignant and non-malignant tissues (benign tumor and normal tissues) were significantly different (P < 0.05). CONCLUSIONS: This improved system is a sensitive and rather precise method for quantifying the AgNOR and PCNA. It provides a valuable objective measurement for differentiating benign and malignant tumors.

Perianal Paget's disease years after rectal adenocarcinoma removal.

BACKGROUND: Perianal Paget's disease often coincides with anorectal carcinoma, which extends into the epidermis from a contiguous organ. OBJECTIVE: Our purpose was to present a patient with perianal Paget's disease who had a rectal adenocarcinoma excised 14 years previously in another hospital and to determine whether there is a relationship between the perianal Paget's disease and the rectal adenocarcinoma. METHODS: We examined the resected specimens of the rectal adenocarcinoma and the perianal Paget's disease histologically. RESULTS: In the resected specimen of the rectal adenocarcinoma, Paget cells were present within the anal epidermis adjacent to the rectal adenocarcinoma. The Paget cells showed the same histochemical and immunohistological findings as the adenocarcinoma cells. CONCLUSION: There was a close relationship between the perianal Paget's disease and the rectal adenocarcinoma. It is probable that the Paget cells were derived from direct spread from the rectal adenocarcinoma.

Long-term outcome of patients with perianal Paget's disease.

BACKGROUND: Perianal Paget's disease (PPD) is a rare intraepithelial adenocarcinoma with a significant rate of recurrence after treatment and high risk of progression to an invasive cancer. PATIENTS AND METHODS: Fourteen patients with a mean follow-up longer than 5 years were studied to determine the outcome after surgical treatment. The immunohistochemical accumulation of p53 protein also was assessed in tissue specimens to evaluate its prognostic role in patients with PPD. RESULTS: Four patients were excluded because of progression to invasive malignancy at the time of diagnosis. Two patients underwent local excision (LE) with macroscopic clearance of the surgical margins; the remaining eight patients underwent wide local excision (WLE), i.e., > 1 cm microscopic clearance of the surgical margins. The actuarial 8-year recurrence rate for patients treated with LE and WLE was 100% and 50% (SE = 17.7), respectively. Progression to invasive carcinoma occurred after a median time of 56 months (range 23-72) in two patients treated with LE and in one of eight patients treated with WLE. All four patients with recurrence after WLE were successfully treated (no further recurrence) with a second WLE. Actuarial 8-year survival was 0% in the LE group and 40% (SE = 21.9) in the WLE group. There was no p53 protein accumulation in any of the ten patients with PPD. CONCLUSIONS: Survival of patients with PPD treated by WLE was higher than that for those treated with LE. Thus, wide local excision is recommended over limited local excision as a preferred treatment for PPD. Follow-up longer than 5 years seems to be indicated because of the risk of late progression to invasive cancer. When PPD does recur, a second WLE may be curative. The absence of accumulated p53 protein suggests that this marker may not have a prognostic role in PPD.

Adenylate cyclase-stimulating, bone-resorbing and B TGF-like activities in canine apocrine cell adenocarcinoma of the anal sac.

Canine apocrine cell adenocarcinoma of the anal sac (APO-AS) is a spontaneously occurring tumor that causes humorally mediated hypercalcemia in 90% of cases. To further define the nature of the responsible mediator in APO-AS, we examined tumor extracts from five APO-AS and four control tumors for adenylate cyclase-stimulating activity (ACSA). All extracts from APO-AS contained potent ACSA, whereas the four control tumors did not. The ACSA extracted from one tumor demonstrated a dose response curve parallel to that of synthetic bovinePTH-(1-34) and was 80% inhibited by Nle8,18,Tyr34 bPTH-(3-34)amide at a concentration of 10(-5) M. Extracts from three APO-AS and three control tumors were also examined for in vitro bone-resorbing activity (BRA). All APO-AS contained significant BRA, stimulating resorption 1.47 to 2.13-fold over basal, whereas none of the control tumors stimulated resorption. Purification of one extract using C18 reverse-phase high pressure liquid chromatography (RP-HPLC) resulted in a single sharp peak of ACSA which was 400-fold purified compared with the initial extract. This pool also contained significant bone-resorbing activity, whereas none of the adjacent pools did. Purification of a second extract using sequential CN and C18 RP-HPLC followed by size exclusion HPLC resulted in material that was at least 10,000-fold purified, and showed co-purification of ACSA and B TGF-like activity.

Hypercalcemia in dogs with adenocarcinoma derived from apocrine glands of the anal sac. Biochemical and histomorphometric investigations.

Hypercalcemia, hypercalciuria, and hyperphosphaturia were present in female dogs with adenocarcinomas derived from apocrine glands of the anal sac (CA). Remission of hypercalcemia accompanied tumor excision in all six dogs undergoing surgery, whereas tumor recurrence or growth of metastases was associated with a return of hypercalcemia. Preoperatively, the plasma concentrations of immunoreactive parathyroid hormone in all dogs were undetectable or in the low normal range. Plasma concentrations of 13,14-dihydro-15-keto-prostaglandin E2 (PGE2M) and serum 1,25-dihydroxyvitamin D were not significantly different from control dogs. Urinary cyclic AMP and hydroxyproline were increased in dogs with CA. No immunoreactive parathyroid hormone was detected in extracts from tumor tissue, and parathyroid glands from dogs with CA had ultrastructural characteristics of secretory inactivity. Lumbar vertebrae from hypercalcemic dogs had decreased trabecular bone volume and increased osteoclastic bone resorption compared with age-matched control dogs. After tumor excision, serum total calcium returned to the normal range, whereas immunoreactive parathyroid hormone increased 2- to 20-fold and 1,25-dihydroxyvitamin D decreased 2- to 8-fold. Postoperative hypocalcemia was not observed. These results indicate that CA produces a hypercalcemic factor other than immunoreactive parathyroid hormone or prostaglandin E2 that increases osteoclastic osteolysis distant from the tumor and results in hypercalcemia, hypercalciuria, and hyperphosphaturia.