The purpose of this study is to describe melanotic tumours and the pathogenesis of these tumours. The focus of this study is on differences between benign and malignant tumours as well as the prognosis one may expect when diagnosing this disease. The mechanisms responsible for the occurrences of the tumours are not yet fully understood. It is believed that factors such as chronic trauma, infections, medications and hormones affect the cell mechanisms in some way. Determinants of the malignancy of the tumour are not completely known.

The purpose of this study is to describe melanotic tumours and the pathogenesis of these tumours. The focus of this study is on differences between benign and malignant tumours as well as the prognosis one may expect when diagnosing this disease. The mechanisms responsible for the occurrences of the tumours are not yet fully understood. It is believed that factors such as chronic trauma, infections, medications and hormones affect the cell mechanisms in some way. Determinants of the malignancy of the tumour are not completely known.

The purpose of this study is to describe melanotic tumours and the pathogenesis of these tumours. The focus of this study is on differences between benign and malignant tumours as well as the prognosis one may expect when diagnosing this disease. The mechanisms responsible for the occurrences of the tumours are not yet fully understood. It is believed that factors such as chronic trauma, infections, medications and hormones affect the cell mechanisms in some way. Determinants of the malignancy of the tumour are not completely known.

Oxytocin is a hormone which plays a crucial role in many reproductive and behavioural functions. It affects many organs and the classical peripheral targets are the mammary glands during lactation and uterus during labour. Oxytocin receptors have recently been described in a variety of normal tissues and primary cell cultures, but also in neoplastic tissues and established neoplastic cell lines, as breast cancer cell lines. The signalling pathways and biological effects of the oxytocin/oxytocin receptor system seem to depend on species, type of tissue, physiological versus neoplastic state and receptor location within the cell membrane.The aim of this project was to find out if the cell proliferation in the canine mammary carcinoma cell line CMT-U27 was affected upon stimulation of oxytocin, and to investigate the presence of oxytocin receptors in these cells. The cell proliferation was examined by using an ELISA-kit, where the absorbance measured is relative to the amount of living cells.

The purpose of this study is to describe melanotic tumours and the pathogenesis of these tumours. The focus of this study is on differences between benign and malignant tumours as well as the prognosis one may expect when diagnosing this disease. The mechanisms responsible for the occurrences of the tumours are not yet fully understood. It is believed that factors such as chronic trauma, infections, medications and hormones affect the cell mechanisms in some way. Determinants of the malignancy of the tumour are not completely known.

I denna studie har förekomst av progesteronreceptorer i olika typer av primära juvertumörer undersökts med hjälp av immunohistokemi. Dessutom har tumörceller från carcinomcellinjen CMT-U27 odlats i olika cellodlingsmedium och exponerats för olika testsubstanser som binder till progesteronreceptorn (progesteron och RU486/mifepristone). Cellernas receptoruttryck och progesteroninnehåll utvärderades med hjälp av ELISA och tumörcellernas viabilitet analyserades med Colorimetric Cell Viability Test. Av resultaten framgår att samtliga undersökta primära juvertumörer uttryckte progesteronreceptorer. De odlade cellerna hade högre cellviabilitet när de odlades utan fetalt bovint serum (FBS). Efter exponering med progesteron minskade tumörcellernas uttryck av progesteronreceptorer, vilket hämmades av mifepristone.

Complete tumour regression is the optimal outcome of cancer therapies. There are however types of tumours that naturally regress. Most of these are benign, dermatological and have an early onset in life. This literature study aims to elucidate the mechanisms behind spontaneous tumour regression. In Libechov Melanoblastoma-Bearing minipigs, an animal-model specifically bred to develop malignant melanoma, the tumours usually involute within three months.

Mammary tumors are the most frequent type of tumors in bitches in Sweden. Many studies have been published concerning mammary tumors, but there is still much to be learned about this disease. One has, since some time ago, had the knowledge that addition to or removal of methyl groups to genes can inhibit or activate gene-expression. Methylation and demethylation is a normal phenomenon in the body and it is essential for the development and survival of the individual. The risk of developing a tumor disease is increased if the global methylationstatus is changed; if oncogenes demethylates (activates) or if tumor suppressor genes methylates (inactivates). In the human medicine one has seen that there are differences in methylationstatus between different tumors. In this study tumor and normal tissue from ten dogs were examined with regard to methylationstatus.

The WT1 gene is a complex gene originally known to suppress cancer in kidneys. Studies of WT1 knockout mice have confirmed the important role of WT1 in the pathogenesis of Wilms? tumour, a tumour which counts for 95% of all childhood renal tumours. In that case the WT1 gene acts as a tumour suppressor gene. Subsequent research has shown that the WT1 gene in many other cases acts as an oncogene, e g in leukemia or lung cancer (even though these cancer forms can emerge as a result of many other aetiological factors).

The dog has often served as a model animal for humans in scientific studies. This is due to the fact that dogs are susceptible to a wide range of diseases which also affect humans. One example is cancer, a condition that affects dogs as well as owners. Neoplastic diseases account for 18-23 % of all deaths in dogs (Bonnet et al., 2005 and Jagielski et al., 2002). Mammary tumor, or tumor of the breast, is the most common tumor form in intact dogs and women (Im et al., 2013). Mammary tumors originate in the udder, and are classified according to their histological characteristics.

Heifer?s growth may be divided into three main phases: calf period, puberty and pregnancy. When the heifers are about three months old a critical period begins. This period ends when the heifer reach puberty and have her first oestrus at around 9-12 months of age. In the critical period the mammary gland starts to grow at a fast rate and Insulin-like growth factor-1 (IGF-1) transport the growth signals to the mammary glands.

Mammary gland neoplasia is one of the most common diseases in the bitch and the most common neoplastic disease. More than 13 % of the female dog population in Sweden suffers from mammary tumors during their lifetime. The disease can affect bitches in all ages but most often middle aged and older dogs. Some breeds such as Poodle and English Setter are predisposed for the disease. The aim of this study was to evaluate if it is possible to improve the post surgical healing process by using a pressure pad.

The development of quantitative, real-time PCR (qPCR) combined with the mapping of the canine genome opens new possibilities in veterinary medicine. This method provides a quick and accurate quantification of the expression of a specific gene at a given point in time and thereby also information of how the gene expression for a certain protein is influenced by various conditions and diseases. One possible area of application is identifying bio markers for cancer. Recently the protein serglycin (the core protein of an intracellular proteoglycan) was found to act as a selective marker for the disease acute myeloid leukemia in humans (Niemann et al, 2007). Serglycin is produced by most hematopoietic cells, although mast cells account for the largest amount of serglycin.

Pseudopregnancy is a condition that is estimated to affect 40 % of all female dogs. Common symptoms are decreased activity level, weight gain, mammary enlargement, milk production, nesting behavior, anorexia and maternal behavior. The symptoms are displayed during metoestrus. Prolactin is one of the causes behind pseudopregnancy, but the full process is not yet known. Due to the fact that the condition affects that many bitches and often is recurrent, it is relevant to examine how the condition affects the bitch?s behavior and performance.

This literature study aims to examine the existence of cancer stem cells in breast cancer. The cancer stem cell theory states that there is a hierarchical organization within a tumour, in which a small subpopulation of the cells can initiate new tumours and maintain tumour growth whilst the bulk of the tumour cannot. These tumour initiating cells have shown to possess many characteristics similar to those of adult stem cells, which is why they are often referred to as cancer stem cells. Both cell types have the capacity of asymmetric division and have shown to possess mechanisms of resistance to both apoptosis and cancer drugs. The cancer stem cell theory elucidates many biological aspects such as the heterogeneity of tumours and the relapse of many cancers after what appeared to be successful treatments.