Læknablaðið : fylgirit - 01.06.1982, Side 53

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EVIDENCE SUGGESTING CYCLOPHOSPHAMIDE TO BE
SELF-DEFEATING AS AN ANTITUMOR AGENT.
M. Lau Laursen, MDf PhD/. Dept. of Medicine
The County Hospital, DK-4ooo Roskilde
Cyclophosphamide (CPA) is widely used due to the
cytotoxic action on lymphoid tissue. CPA is also
used for treatment of neoplastic diseases, either
alone or combined with other cytotoxic drugs, and
has proved successful in controlling certain kinds
of relatively rare cancers, but for more common
cancers a beneficial effect has only been obtained
temporarily.
In BALB/c mice the remission obtained by CPA
treatment of a syngeneic mammary carcinoma was sig-
nificantly reduced when the mice, before subcuta-
neous challenge and treatment, were immunized with
the tumor cells weekly by gavage for 5 weeks.
Immunization with tumor cells given by gavage
induces under certain conditions factors able to
reduce antigenicity and immunogenicity of the tumor
cells.
Findings suggesting that the antigenicity of the
mammary tumor cells might be an iraportant, perhaps
critical, factor in obtaining successful therapy
with CPA will be presented.
In other experiments treatment with CPA was
found to facilitate induction of factors able to
mask antigenic determinants on the cell membrane of
tumor cells whether the immunizing doses of tumor
cells were given through the gastric or by the
subcutaneous route.
In following the logic of such experiments, CPA
does appear to be self-defeating as an anti-neopla-
stic drug.