Biological therapy utilizing dendritic cells shows promise in producing anti-cancer responses in patients with melanoma and breast cancer, according to a recent article published in the journal Cancer. Biological therapy is a type of therapy that utilizes the patient’s own immune system to attack cancer cells.
Immune cells distinguish between healthy cells and “foreign” cells in the body through differences in specific proteins attached to the surface of all cells, called antigens. Dendritic cells (DCs) are a crucial component of the immune system, stimulating an initial immune response against “foreign” cells. They do this by “displaying” foreign antigens to other immune cells. Small proteins, called heat shock proteins (HSP), work in combination with DCs and assist in the facilitation of eliciting an immune response.
Previous studies have implicated a direct association between increased numbers of DCs present within a variety of different cancers, including colorectal1, gastric2, cervical3, lung4 and nasopharyngeal5, and improved patient outcomes. This has stimulated research efforts to investigate the practical application and outcomes of injecting DCs directly into a patient’s cancer in order to stimulate anti-cancer responses.
A recent clinical trial evaluated anti-cancer responses of 10 patients whose cancer was directly injected with DCs. Patients involved in the trial had either advanced breast cancer or melanoma that had spread and was no longer responding to standard therapies. The injections containing DCs were prepared from blood that was drawn from the patient’s vein. The patient’s blood was then filtered so that DCs could be isolated. The isolated DCs were injected directly into the patient’s cancer. Beginning as early as 4 days following the injections, 6 patients experienced regression of their cancer. Two patients experienced a regression of cancer in sites that were not injected.
Two to 6 weeks following the injections, a sample of cells was obtained from each cancer site. Dendritic cells, heat shock proteins and lymphocytes (certain immune cells stimulated by DCs) were observed in cancer sites that had regressed following treatment. Conversely, DCs and lymphocytes were scarce in cancer sites that had not regressed following treatment.
These results indicate that direct injections of DCs into cancers may elicit an immune response against breast or melanoma cancer cells. This novel biological therapy approach is exciting for patients who have stopped responding to standard available treatments and have no alternative options. Future clinical trials are warranted involving treatment with DCs for cancer and investigation of the role of heat shock proteins.
Patients with breast cancer or melanoma that has stopped responding to therapies may wish to discuss the risks and benefits of participating in a clinical trial further evaluating DC injections or other biological therapy
(Cancer, Vol 89, No 12, pp 2646-2654, 2000)
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