Wim Misdorp

Genomic organization of the canine p53 gene and its mutational status in canine mammary neoplasia

To determine whether canine malignancies share common genetic lesions with their human counterparts, and are thus potentially interesting model systems in which to pose questions regarding tumor etiology and progression, we have elucidated the entire exon/intron structure of the canine p53 gene. A search for p53 gene abnormalities in mammary tumor tissue was undertaken utilizing single strand conformation polymorphism analysis. Mutations were detected in exons 4, 5, 6, and 7 of the p53 gene and consisted of nonsense, splicing, and frameshift mutations. None of 11 benign tumors and 6 of 40 primary carcinomas (15%) were found to harbor subtle p53 mutations. In 14 carcinomas examined the results in primary tumors and metastases were the same. These findings implicate involvement of this gene in the genesis of some malignant canine tumors, in a fashion similar to their human counterparts.

Equine sarcoid: BCG immunotherapy compared to cryosurgery in a prospective randomised clinical trial

SummaryA total of 30 horses with single or multiple sarcoid tumors of the skin were randomly divided into three treatment groups: (i) cryosurgical treatment, (ii) intralesional immunotherapy with a live BCG vaccine, (iii) intralesional immunotherapy with a BCG cell wall preparation. Complete tumour regression was obtained in all 10 crysurgically treated horses, in 6 of 10 live BCG treated horses, and in 7 of 10 BCG cell wall treated horses. One live BCG and 2 BCG cell wall treated horses showed partial tumour regression of more than 50% of the tumour area. Eleven horses with sarcoid tumours were not eligible for random allocation in the trial because unfavourable site or size of the tumour precluded cryosurgical treatment. These animals were treated with BCG cell wall vaccine except for 1 animal, which was treated with live BCG. In 4 cases this treatment was combined with cytoreductive surgery of the tumour. In this prognostically unfavourable group 8 animals showed complete tumour regression and 3 animals did not respond.Regression after BCG immunotherapy appeared to correlate with size (larger tumours worse response) and localization of the sarcoid (less favourable results in the limb), and increase in peripheral blood leucocytes after the first injection. Horses with a positive delayed type hypersensitivity reaction to PPD before the start of treatment showed a tendency to more favourable prognosis than PPD negative horses. No correlation was present between regression and single or multiple presence of sarcoids, increase in body temperature after injection of BCG and the formation of specific antibodies to BCG. None of the cured animals have shown tumour recurrence 3 to 40 months following treatment.

Local interleukin-2 therapy in bovine ocular squamous cell carcinoma. A pilot study.

SummaryFive cows bearing bovine ocular squamous cell carcinoma (BOSCC) were treated with low doses of recombinant human interleukin-2 (rhIL-2). A dose of 2500 U rhIL-2 was injected intralesionally and another 2500 U were injected into the subparotid regional lymph node once a day during a period of 5 consecutive days. This cycle of 5 days was repeated after an interval of 2 days. Total regression of the tumor was observed in three out of five animals. One cow showed tumor regression (> 80%) accompanied by metastases to the regional lymph node that were observed from the fifth week after the beginning of the treatment. Growth of the tumor of the fifth animal was retarded after treatment. In vitro proliferation of peripheral blood lymphocytes was investigated in two animals and tumor-infiltrating lymphocytes in one animal during incubation in various rhIL-2 concentrations. Cytotoxic activity of both cell populations against P815, Yac-1 and BOSCC-derived cell lines increased during incubation with rhIL-2. Cultured BOSCC-infiltrating lymphocytes showed predominant killing of the BOSCC-derived autologous cell line after 4 weeks of culture. Preliminary phenotype analysis did not give conclusive results with respect to the types of cells responsible for killing.

Polyethylene glycol-L-asparaginase versus native L-asparaginase in canine non-Hodgkin's lymphoma

42 dogs with non-Hodgkins lymphoma (NHL) were randomized for treatment with either PEG-L-asparaginase 10 IU/kg intramuscularly (n = 22) or L-asparaginase 400 IU/kg intraperitoneally (n = 20). Another 20 dogs were treated with either PEG-L-asparaginase 30 IU/kg (n = 10) or L-asparaginase 400 IU/kg (n = 10). Each treatment protocol consisted of two asparaginase treatments followed by a 10-week period of induction chemotherapy and then maintenance on asparaginase until progression occurred. No significant differences were found between treatments in the response rates after 2 weeks of asparaginase therapy or in the time to relapse, the time to treatment failure or the remission period. The reaction to asparaginase after the initial 2 weeks was a prognostic factor for the total duration of remission under asparaginase maintenance therapy. No side-effects were noted in the dogs treated with PEG-L-asparaginase, whereas 14 (48%) of the L-asparaginase treated dogs had side-effects related to this drug, including anaphylactic shock (9), anorexia or vomiting (4), hypersensitivity-related oedema (3), seizures (1) and acute pancreatitis (1). No abnormalities in clotting times, fibrinogen levels or antithrombin-III levels were found in any of the 62 dogs. PEG-L-asparaginase has the same anti-tumour activity as native L-asparaginase in dogs with NHL, but lacks side-effects.

Intratumoral BCG and Corynebacterium parvum therapy of canine mammary tumours before radical mastectomy

SummaryIn two parallel studies, bitches with mammary tumour received single intralesional injections of BCG (1 mg: 107 living bacteria) and Corybacterium parvum (109 killed bacteria) (53 bitches) or C. parvum alone (129 bitches) at the same dosage. Control groups received injections, following the same protocol, of 1 ml BCG suspension medium diluted in saline in the first study (51 bitches) or no injections at all (120 bitches in the second study).A block dissection, including mammary tumours, adjacent mammary glands, and regional lymph nodes, was performed 2 weeks later in all animals. On the basis of histologically confirmed malignant tumours, 48 bitches (25 treated by immunotherapy and 23 controls) in the first study and 67 bitches (30 treated by immunotherapy and 37 controls) in the second study remained for postsurgical follow-up.The clinical tolerance of the treatment was generally good. No significant differences were found in cumulative survival rates between treated and control group in either studies.

Clinico-pathological aspects of immunotherapy by intralesional injection of BCG cell walls or live BCG in bovine ocular squamous cell carcinoma

SummaryBovine ocular squamous cell carcinoma (BOSCC) of clinical stage I, mostly situated in the third eyelid, was chosen as a therapy model for squamous cell carcinoma of the head and neck in humans. Block resection was found to be the best method of treatment. Regression was noticed in 19 out of 30 cows treated intratumourously with a single injection of live BCG or BCG cell wall vaccine, followed by recurrence in 8 cases. In 2 untreated cows, complete lasting regression occurred. Regression was significantly more frequently encountered in intratumourously treated cows than in controls. Regression was associated with a high mitotic index, severe infiltrating growth and small amounts of cellular (lymphoid) infiltration.Metastasis was found in 14 out of 50 cows: 5 in 10 untreated controls, 8 in 30 BCG treated cows and 1 in 10 surgically treated cows. The growth rate of progressively growing untreated and of some treated tumours was not associated with the mitotic index nor with other morphological characteristics tested. The mitotic index was found to be higher in the deep infiltrating layer than in the superficial layer of the primary tumour, suggesting that a single biopsy is not sufficiently representative for cell kinetic studies.Animals were maintained under the guidelines set forth by the Faculty of Veterinary Medicine, State University, Utrecht, The Netherlands

Immunotherapy of bovine ocular squamous cell carcinoma by repeated intralesional injections of live bacillus Calmette-Guérin (BCG) or BCG cell walls

SummaryThirty cows of the Dutch Friesian and the Maas-Rijn-Ijssel breed with histologically confirmed ocular squamous cell carcinoma were treated by repeated intralesional injection of live bacillus Calmette-Guérin (BCG) (n = 14) or a BCG cell-wall vaccine (n = 16). Complete regression of the primary tumour was observed in 64% and 57% of the animals respectively. In the 2-year follow-up period there was no recurrence of primary tumours. This sharply contrasts with the recurrence frequency (40%–50%) after complete remission induced by a single intralesional injection with BCG, observed in an earlier study. In 1 animal a new primary tumour developed. At necropsy metastases were present in 33% of the treated animals: in 3 of 17 animals that showed complete regression of the primary tumour and in 7 of 13 animals with partial regression or progressive disease. This did not differ significantly from results obtained after a single treatment (27%). Delayed-type hypersensitivity toM. bovis purified protein derivative (PPD) was more persistent in animals showing regression of the primary tumour than in non-responding animals. Of the animals with a positive PPD response 6 months after treatment, 79% showed tumour regression. Regression was observed in only 28% of the animals not responding to PPD after the same period of time. In conclusion: (a) recurrence of the primary tumour was not observed after repeated BCG treatment; (b) the frequency of metastases was not decreased compared to results obtained with a single treatment; (c) regression was correlated with a positive delayed-type hypersensitivity reaction to PPD (P <0.05) 6 months after treatment; (d) no significant differences were observed when the clinical results of treatment with live BCG and the BCG cell wall vaccine were compared.

Immune reactivity in cattle with ocular squamous cell carcinoma after intralesional BCG immunotherapy

SummaryLymphocyte stimulation with Con A and specific immune reactivity to BCG (antibody formation to BCG and DTH reaction to PPD) were determined in BCG-treated, surgically treated and untreated cows with ocular squamous cell carcinoma. In tumor-bearing cows the Con A-induced proliferation of lymphocytes was reduced when compared to healthy controls. This suppression consisted of a reduced blastogenic response to Con A of lymphocytes from tumor-bearing cows, and the presence of a factor in the sera of these animals, as these sera suppressed the blastogenic response of lymphocytes from healthy cows. BCG had only a minor influence on the suppressive activity. Antibodies to BCG were demonstrated in 50% of the BCG-treated animals. The formation of antibodies was not influenced by intradermal injection of PPD of Mycobacterium bovis. Absorption of a BCG antibody containing serum with BOSCC tumor extracts did not reveal the existence of cross reacting antigens between BCG and BOSCC. Pretherapeutic and posttherapeutic Con A reactivity could not be correlated with clinical response. Of the 30 BCG treated cows 29 developed a positive DTH reaction to PPD. Correlation between clinical response and immune reactivity was seen only with regard to the DTH reaction to PPD: this reaction remained positive for a longer period after treatment in animals with a favorable clinical outcome than in nonresponding animals.

Benign proliferative lesions of the breast; Workshop report

INTRODUCTION THE WORKSHOP on benign proliferative lesions of the human mammary gland considered new information and sought ways for future work of clinical usefulness. Abstracts of the posters which were discussed in the workshop are included in the Abstract book of the conference. For this purpose proliferative lesions are defined as those having the essential characteristic of epithelial growth by cell mitosis. This epithelial growth is usually organoid in character with stromal participation. The stromal participation is classically viewed as reactive or inductive in kind, and often includes the multiplication of fi‘broblasts, the deposition of collagen and the formation of new blood vessels, as well as greater or lesser infiltrations by chronic inflammatory cells. The crucial current and future problem for the human mammary biologist is to clearly define the differing biological potentials, natural histories and precancerous potentials of the variety of epithelial proliferations classically found in the mammary gland. To these ends the information reported and discussed by the contributors and participants of our workshop was organized under three general headings: (1) morphology and histogenesis; (2) determination of risk factors; and (3) endocrinology. All of the discussions were related to the central theme of benign proliferative lesions of the human mammary gland.