In situ carcinoma-associated immunogenicity: therapeutic and prophylactic implications in breast cancer patients

The fetal antigen hypothesis for breast cancer, revisited

The fetal antigen hypothesis was proposed over a decade ago to explain the small, short-term promotional effect, as well as part of the long-term protective effect that pregnancy has on breast cancer risk. The hypothesis is based on immune interaction between mother and fetus, and postulates that breast cancer genes which a women's fetus inherits from her mate may be indirectly involved in protecting the woman against breast cancer. This article addresses new epidemiological data pertaining to the hypothesis plus the growing evidence that prenatal reproductive factors are important determinants of breast cancer risk. It also suggests that iso-immunization from pregnancy, similar to Rh iso-immunization, can produce immunity against breast cancer. The proposed mechanism provides a plan for development of a vaccine against breast cancer. If the fetal antigen hypothesis is valid for breast cancer, the mechanism behind it is likely to apply to other cancers, even cancers that are found in males, since males can be affected be the prenatal component of this mechanism.

Tumorigenicity of interleukin-2 (IL-2)-cDNA-transfected L1210 lymphoma and its in vivo variants is modulated by changes in IL-2 expression; potential therapeutic implications

To study parameters that affect the tumorigenicity of L1210 lymphoma we have analyzed the structure of MHC class I antigens of this tumor. In addition this tumor was transfected with interleukin-2 (IL-2) cDNA in order to determine the effects of high concentrations of IL-2 within the tumor environment. The nucleotide sequence of the class I Kd, Dd and Ld mRNAs from this tumor showed that the encoded amino acid sequence of the corresponding antigens is normal, thus suggesting that the tumorigenicity of L1210 lymphoma is not due to defective antigen presentation to tumor-specific cytotoxic T cells. In contrast, induction of IL-2 expression by cDNA transfection led to loss of tumorigenicity of the IL-2-secreting tumor cells. However, a fraction of long-term-surviving mice developed progressively growing variant tumors that showed substantial decrease or loss of IL-2 expression. These results suggest that IL-2 secretion by tumors is suicidal but, because of tumor heterogeneity, IL-2-loss-variant tumors may arise that are able to escape the immune defenses of the host. The observed consistent loss of IL-2 expression in variant tumors implies that specific targeting of large quantities of IL-2 to tumor cells may be a valuable approach to immunotherapy of cancer. In addition we find that under specific gamma ray irradiation IL-2-secreting tumor cells lose their ability to multiply yet continue to secrete IL-2 at levels equivalent to those secreted by unirradiated cells. Such IL-2-secreting irradiated tumor cells were found to be superior immunogens in comparison to the irradiated parental tumor cells, suggesting their use as tumor vaccines.