Textbook of Medical-Surgical Nursing 3e

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Chapter 11

Oncology: Nursing management in cancer care

has three main functions: to stimulate control or modify the immune response including the development of antibodies, to inhibit the development of the tumour’s own blood supply, or to allow the transfer of genetic material to alter the function, production and repair of cancer cells (Batchelor, 2006). Non-specific biological response modifiers Some of the early investigations of the stimulation of the immune system involved non-specific agents such as Bacille Calmette-Guérin (BCG) and Corynebacterium parvum. When injected into the patient, these agents serve as antigens that stimulate an immune response. The hope is that the stimulated immune system will then eradicate malignant cells. Extensive animal and human investigations with BCG have shown promising results, especially in treating localised malignant melanoma. Additionally, BCG is considered to be a standard form of treatment for localised bladder cancer (Creel, 2007). Use of non-specific agents in advanced cancer remains limited, however, and research is continuing in an effort to identify other uses and other agents. Monoclonal antibodies Monoclonal antibodies (MoAbs), another type of BRM, became available through technological advances, enabling investigators to grow and produce specific antibodies for

specific malignant cells. Theoretically, this type of specificity allows the MoAb to destroy the cancer cells and spare normal cells. The specificity of MoAbs is dependent on identifying key antigen proteins on the surface of tumours that are not present on normal tissues. These targets when blocked lead to apoptosis by disrupting communication between cells. There are several categories of these tumour-associated antigens: oncofetal antigens such as CEA, a prominent tumour marker identified in colon cancer (Kay, 2006). MoAbs bind with specific tumour cell antigens and block the ability of the tumour cell to reproduce or deliver cytotoxic agents directly to the tumour cell causing cell death. The production of MoAbs involves injecting tumour cells that act as antigens into mice. Antibodies made in response to injected antigens can be found in the spleen of the mouse. Antibody-producing spleen cells are combined with a cancer cell that has the ability to grow indefinitely in culture medium and continue producing more antibodies. The combination of spleen cells and the cancer cells is referred to as a hybrid- oma. From hybridomas that continue to grow in the culture medium, the desired antibodies are harvested, purified and prepared for diagnostic or therapeutic use (Figure 11-4). Alternative methods of producing MoAbs using human or genetically engineered sources are under investigation.

Cancer cells

Spleen cells with antibody- producing cells

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Antigen injected into mouse

Hybridomas (fusion of two different cells)

Monoclonal antibodies extracted for processing for diagnostic and therapeutic use

Culture dish

Monoclonal antibody

Hybridomas multiply in culture medium

Figure 11-4  Antibody-producing spleen cells are fused with cancer cells. This process produces cells called hybridomas. These cells, which can grow indefinitely in a culture medium, produce antibodies that are harvested, purified and prepared for diagnostic or treatment purposes.