Chapter 11
Oncology: Nursing management in cancer care
261
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.
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
+
=
Antigen injected
into mouse
Spleen cells
with antibody-
producing cells
Cancer cells
Hybridomas
(fusion of two
different cells)
Monoclonal
antibody
Culture dish
Hybridomas multiply in culture medium
Monoclonal antibodies
extracted for processing
for diagnostic
and therapeutic use
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.
