What Is Canine Lymphoma Biology Essay

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Canine Lymphoma. The lymphatic system, which includes lymph nodes and spleen, plays an important role in the protective immune system of the body against antigens. Lymph nodes contain many types of white blood cells that play an important role in the fight of the organism against infection. As a result, the role of lymph nodes is to filter a circulating blood and help in removing unwanted antigens (Bhang 2006).

Lymph nodes are located in various zones throughout the body; the location of some of them can be found easily, and some are deeper in the body, and to find them, usually require special x-ray equipment. Lymph nodes filter the material from the tissue and remove foreign bodies, such as bacteria and viruses. Swollen glands occur for different reasons: in response to stimulation of antigens (such as bacterial infection), the infection within the lymph nodes, or in the case of cancer such as lymphoma.

Canine lymphoma is a type of malignant tumor that affects primarily the lymphatic system of the organism. It ranges from 7 to 24% of all tumor processes.

This disease can happen in dogs, cats, ferrets and other animals. But in this work is devoted to only dogs` canine lymphoma (Morrison 2004).

Canine lymphoma is usually a malignant disease of the lymph glands of dogs.

It can also affect other organs such as the liver, nervous system, and skin. Usually canine lymphoma affects anatomically distinct sites throughout the body. Therefore, treatment should similarly affect the whole body.

The lymphatic system consists of lymph nodes, combined with the system of small vessels. It is an important part of the immune system and plays a major role in protecting the body against infections. The main component of the immune system is lymphocytes, which are the type of blood cells. When lymphoma occurs, the "tumor" lymphocytes are dividing indefinitely; their descendants populate the lymph nodes and/or various internal organs, causing a breach of their normal work (Ettinger 1995).

Causes of Canine lymphoma in dogs are unknown.

Lymphoma is a cancer of lymphocytes or white blood cells. There are many different types of lymphoma in dogs, as well as in humans, although at present, it is a concept that really starts to reach a broad veterinary consciousness. Different types of lymphoma are the result of a malignant transformation of various types of lymphocytes, or as a result, various specific DNA abnormalities, acquired during the life of the individual dog. Most types of lymphoma respond favorably to the correct assignment of chemotherapy.

So, the main types of canine lymphoma are: anatomical, histology (cell type) and immunophenotype.

Symptoms. Typically, the first symptom of canine lymphoma is a significant increase in the size of lymph nodes, for example, in the neck area. Unlike infectious diseases, the sizes of lymph nodes do not decrease with time and with antibiotic treatment. But the general condition of the animal may be normal for some time. Other symptoms occurring in lymphoma, are weakness, fever, weight loss, indigestion (diarrhea, vomiting), and even blindness. While the localization of lymphoma, for example, in the organs of the thoracic cavity or the gastrointestinal tract, there may be symptoms of dysfunction of the organ.

In medical practice, doctors always take a part of the affected lymph node or the entire lymph node for analysis. In veterinary medicine the cytological study of lymph node punctuates is used more often.

Punctate is taken with the help of syringe; anesthesia or anesthesia is not required. Simplicity, relatively low cost, fast obtaining of results, high reliability under typical clinical symptoms explain the wide dissemination of this method. However, in doubtful cases, the lymph node is removed and sent for analysis. This procedure is a small operation and is performed under general anesthesia. It is possible to take the material (lymph node tissue) without general anesthesia - with a special biopsy needle, but in veterinary medicine this method is still limited because of the high cost of biopsy needles (Kaneene 1999).

The material from the affected lymph node is sent to a medical study of Pathomorphology, whose main task is to identify whether the material under study contain tumor (lymphoma) cells.

So, the main methods to put the diagnosis are: cytology (ideal for screening, but doesn’t give exact data); biopsy (allows determining the extent of disease); biochemistry and haematology.

Treatment. Usually, the diagnosis of lymphoma is a complex task that includes the use of multiple different tests to exclude other ordinary disease. The veterinarian should collect blood and urine for analysis of pathologies, the identification of signs of other diseases, and to assess the activities of bodies. This is important not only for eliminating the possibility of other diseases, but also to assess the state of the animal before the course of treatment. Radiographs and ultrasound are used for the detection of lymphoma, which are inaccessible while the physical examination, such as lymphoma, affecting the spleen or gastrointestinal tract. In the end, tissue samples are taken lymph nodes or organs and viewed under a microscope for cancer cells (Nyland 2002).

The selection of the program of treatment depends on the type of lymphoma and the patient's condition. Chemotherapy is used for the treatment of lymphoma. The chemotherapy protocols include drugs such as cyclophosphamide, vincristine, doxorubicin, prednisolone. Treatment consists of two parts:

- Chemotherapy itself: the injection of cytostatic drugs (drugs that suppress the growth of tumor cells);

- The treatment of complications, which cause cytostatics. Chemotherapeutic medicine not only suppresses tumor growth, but also damages virtually all normal tissues. First of all, quickly updated cells of the digestive tract, bone marrow, hair follicles, etc. are affected. The treatment of complications of chemotherapy is varied and depends on their manifestations in each dog (Bean 2002).

The frequency and mode of administration of chemotherapy drugs depend on the chosen treatment regimens. Usually clinics use intravenous injection of cytostatics 1 time in 3 weeks. Question on the number of courses required for stable remission is the most complicated among veterinary oncologists and there is no consensus about it now. The problem lies in the so-called "drug resistance", which occurs in tumor cells after discontinuation of treatment. It turns out that when the disease returns, then those drugs that were used in the first stage, are no longer able to suppress tumor growth, and others should be picked up.

The main purpose of treatment of lymphoma in dogs is to increase the duration and quality of life of the patient. With the help of chemotherapy it is usually possible to achieve remission of disease with the duration 6-8 months. According to statistics, the average life expectancy in the application of chemotherapy is 9-12 months. Some veterinarians are sure that if the dog’s general condition is bad, sometimes it is better to use only prednisolone. Use of prednisolone in mono can improve the condition of the animal with lymphoma, but does not affect life expectancy. Average life expectancy for such treatment is 1-2 months (Miller 2009).

Thus, the treatment of canine lymphoma consists of chemotherapy. Lymphoma is considered to be a systemic disease that makes surgery and irradiation impractical and inefficient. There are a wide variety of chemotherapy protocols and drugs that are currently used for treatment of lymphoma. Chemotherapy usually consists of a combination of injectable drugs, introduced weekly and drugs used orally. Many protocols of chemotherapy include commonly used drugs, such as cyclophosphamide, vincristine, doxorubicin, and prednisolone. Chemotherapy can change the course of treatment, depending on performance. The protocol of the University of Wisconsin is one of the most popular among the veterinary oncologists. Most veterinarians can assign chemotherapy and successfully manage it, but initially it is better for the owners of dogs to seek the advice of veterinary oncologists who is able to offer further guidance and information for treatment (Freedman 2005).

There is also a need to show the overview of epidemiology of cancer in dogs, made of materials, written by Kelsey, Moore, and Glickman (Kelsey1998).

Nearly 2/3 of American households have at least one dog.

In the U.S., approximately 4 out of every thousand dogs each year are diagnosed with cancer. The most common diagnoses are:

Male dog

Female dog

Type of cancer

% from the total

Type of cancer

% from the total

Connective tissue






Connective tissue


Skin (melanoma)


Skin (melanoma)


Maw and Throat






Maw and Throat




Liver and bile ducts


Stomach and intestines




Thus, canine lymphoma is a cancer of immune system cells. Lymphoma in dogs is very similar to the humans` lymphoma of non-Hodgkin type. In dogs, this type of tumor usually occurs with age. Males and females exposed to the disease in about equal measure. Sterilization and castration has no effect on the development of the disease, although the pure-bred dogs are a bit more prone to it than half-blood (Kelsey1998).

There is a very weak relationship between the development of canine lymphoma and the use of herbicides. There is also the link between canine lymphoma and electromagnetic fields. Dogs living in homes near high-voltage lines, have the risk of developing lymphoma in 7 times higher than that of the dogs which live far from them.

So, there are several measures to reduce the incidence of cancer (including lymphoma) in dogs. They include:

- Sterilization of female dogs before the first estrus;

- Castration of male dogs with not drooping down testes;

- Limiting contact of dog with drugs from fleas and mites, cigarette smoke and asbestos;

- To avoid dog’s walk on lawns or fields treated with herbicides;

- To avoid spending a lot of time in the zone of strong electromagnetic radiation.

So, canine lymphoma is a type of cancer which affects the immune system. It ranges from 7 to 24% of all tumor processes. It can happen in dogs, cats, ferrets and other animals. The canine lymphoma is a dangerous disease, because according to statistics, the average life expectancy in the application of chemotherapy is only 9-12 months; and without chemotherapy it is just couple months.