|Please use this page as for reference to specific and general information for canine and feline melanomas. I search the web and pub med for the best references to this horrid disease in an attempt to provide a general background and also details that can help you discuss matters with your trusted vet. I believe in miracles so never give up hope. These articles are as of yet not arranged in any particular order, or rather the order I found the most "interesting and helpful" in understand this form of cancer.|
"n general, skin melanomas tend to be benign, and those in the mouth, toes, or eyes tend to be malignant.
In humans, melanoma arises due to mutations induced by repeated, intense exposure to ultraviolet light (for example, frequent tanning or working outdoors). This does not seem to be a major factor in dogs, as in most breeds the hair coat affords them protection from sunlight. However, pigment cells divide every time there is injury to the skin, or if there is constant trauma (for example, areas where dogs constantly scratch or lick). Nevertheless, risk factors for canine melanoma are not well established."" Specific genes that are responsible for familial melanoma have been identified in humans and in mice. In dogs, there appears to be a predisposition among certain breeds or families to develop specific types of cancer, suggesting that a hereditary component may be important in the development or progression of the disease."
"About 80% of canine oral melanomas respond to a high dose radiation fractionated over three doses (days 0,7,21). In about half the cases, the oral tumor completely disappears but the prevalence of fatal distant metastasis is not affected. Even though eventual case fatality rates probably remain the same, the quality of life is greatly improved and the need for premature euthanasia because of locally destructive growth is greatly reduced."
"The most important prognostic factors in determining the course of the disease are tumor stage, size, mitotic activity, and evidence of tumor recurrence after a prior treatment. Metastasis to lung and regional lymph nodes occurs in at least 50% of oropharyngeal malignant melanomas.2 "
"Various treatments for malignant melanoma have been attempted, but clinical response has been less than ideal. Melanomas generally exhibit poor response to chemotherapy. Surgical excision (with wide margins) often is performed if the neoplasm is isolated. Malignant melanomas on digits or distal limbs are sometimes amenable to amputation. However, surgery is often impractical because of the anatomical location of the neoplasm or inability to achieve sufficient surgical margins at excision.
Cryosurgery, photocoagulation using Nd-YAG lasers, radiation therapy, and intralesional cisplatin implants have been performed with variable success. For localized neoplasms, combining two methods of treatment may improve survival rates."
Diagnostic records from 338 canine oral melanomas in 338 dogs received at the Veterinary Medical Diagnostic Laboratory (1992-1999) were reviewed. Of these tumors, 122 plus an additional 7 metastatic melanomas of unknown origin were selected for clinical follow-up, histologic review, and immunohistochemistry. Chow Chow, Golden Retriever, and Pekingese/Poodle mix breeds were overrepresented, whereas Boxer and German Shepherd breeds were underrepresented. There was no gender predisposition and the average age at presentation was 11.4 years. Forty-nine dogs were euthanized due to recurrence or metastasis. The average postsurgical survival time was 173 days. The gingiva and the labial mucosa were the most common sites. Most tumors were composed of either polygonal cells (27 cases, 20.9%), spindle cells (44 cases, 34.1%), or a mixture of the two (polygonal and spindle) (54 cases, 41.9%). Clear cell (3 cases, 2.3%) and adenoid/papillary (1 case, 0.8%) patterns were uncommon. The metastases of 6/6 oral melanomas had morphologic and immunohistochemical features similar to those of the primary tumors. Immunohistochemically, Melan A was detected in 113/122 oral (92.6%) and 5/7 (71.9%) metastatic melanomas. Only 4/163 nonmelanocytic tumors were focally and weakly positive for Melan A. Antibodies against vimentin, S100 protein, and neuron-specific enolase stained 129 (100%), 98 (76%), and 115 (89.1%) of 129 melanomas, respectively. Antibodies against other melanocytic-associated antigens (tyrosinase, glycoprotein 100) did not yield adequate staining. We conclude that Melan A is a specific and sensitive marker for canine melanomas.
These canine data are similar to human results recently announced by Valentis. A Phase I/II clinical trial of an IL-2 plus superantigen B (SEB) gene medicine in patients with malignant melanoma showed that the gene medicine caused regression of injected tumors and a systemic anti-tumor immune response, and was safe and well tolerated.
Record 3 AUTHOR: Ohashi E, Hong SH, Takahashi T, Nakagawa T, Mochizuki M, Nishimura R, Sasak N
TITLE: Effect of retinoids on growth inhibition of two canine melanoma cell lines.
This result suggests that retinoids used in this study did not induce differentiation, apoptosis, and growth inhibition of the canine melanoma cell lines
Use of carboplatin for treatment of dogs with malignant melanoma: 27 cases (1989-2000).CONCLUSIONS AND CLINICAL RELEVANCE: Carboplatin had activity against macroscopic spontaneously occurring malignant melanomas in dogs and should be considered as an adjunctive treatment for microscopic local or metastatic tumors. Gastrointestinal toxicosis was associated with body weight. Because small dogs are more likely to have adverse gastrointestinal effects, gastrointestinal protectants should be considered for these patients.
Apparent pokeweed mitogen cure of metastatic gum melanoma in an older dog.
Feline iris melanomas -" enucleation is recommended"-EYE REMOVAL-
"uveal melanomas are generally benign with a very low incidence of metastasis. "
may be highly malignant
amenable to diode laser photocoagulation
These data indicate that clinoptilolite treatment might affect cancer growth by attenuating survival signals and inducing tumor suppressor genes in treated cells.
"Development of a vaccine to treat advanced melanoma has progressed with the introduction of a commercial product by Australian company, Australian Vaccine Technologies (AVT) and the release of encouraging preliminary trial results by two Queensland research bodies. The commercial vaccine, M-VAX, was developed in the United States by AVAX Technologies. The vaccine is prepared by treating cells extracted from lymph nodes surgically removed from a patient with advanced melanoma and re-injecting these into the patient's body. The treated cells teach the patient's immune system to recognise the tumour cells as foreign and destroy them."
" Japanese scientists have used olive oil as an after-sun lotion to slow tumour growth in mice. Olive oil is a proven source of antioxidants, which are thought to protect against UV damage to the skin. Hairless mice daubed with extra virgin olive oil (regular olive oil proved ineffective) showed much slower development of skin tumours than untreated mice. The tumours that did develop in the treated mice were also much smaller and less frequent. Current Status The researchers stress that they do not consider virgin olive oil a sunscreen but that its use after exposure to the sun could help protect the skin from harmful UV damage. Extensive further trials are required to confirm this affect. "
"Malignant melanomas, the most dangerous from of skin cancer, can often be cured if detected and treated early. However, the cancer spreads quickly and if undetected is usually fatal. A recent study has indicated a promising line of research, which might slow the spread of the disease and make it more responsive to treatment. Researchers have discovered that a feature of the cancer is the mutation, or de-activation, of a gene, which would otherwise make cancer, cells more responsive to chemotherapy treatment. The study, reported in the scientific journal Nature, has shown that the 'suicide gene' is not actually killed by the cancer but is merely disabled and is still in full working order. The researchers suggest that restoring the gene could increase the sensitivity of a malignant melanoma to chemotherapy and improve patient treatment."
Non-ocular melanoma is considered to be a rare neoplasm in cats; however, more than150 cases have been reported in the literature since 1961. The objective of this study was to characterise this tumour better by evaluating case outcome and survival data for cats with melanoma and to compare clinical and histopathological findings with those of previous reports. Twenty-three feline non-ocular melanomas were identified, the most common locations being the nose, digit and pinna. Cats with digital melanomas had survival rates similar to their canine counterparts. Histological assignation of benignity, malignancy or junctional activity was not found to be an accurate predictor of clinical behaviour. Melanoma should be considered as a differential diagnosis for cats presenting with pigmented or non-pigmented masses and histopathology is essential for definitive diagnosis, as other tumours may clinically appear quite similar. Regular follow-up examinations are recommended indefinitely for benign or malignant feline melanomas.
Melan A is a melanocytic differentiation antigen recognized by autologous cytotoxic T lymphocytes. It is a product of the MART-1 gene and is specific to melanoma tumors and melanoma cell lines.