Long-term protective effect of mature DC-LAMP+ dendritic cell accumulation in sentinel lymph nodes containing micrometastatic melanoma

1alpha,25-Dihydroxyvitamin D(3) to skew intratumoral levels of immune inhibitory CD34(+) progenitor cells into dendritic cells

OBJECTIVES

Prior studies showed that immune inhibitory CD34(+) progenitor cells, whose numbers are increased in head and neck squamous cell carcinoma (HNSCC) patients, can be differentiated into immune stimulatory dendritic cells by culture with 1alpha,25-dihydroxyvitamin D(3) (1,25[OH](2)D(3)). This was extended to a pilot study to diminish intratumoral levels of CD34(+) progenitor cells by inducing their maturation into dendritic cells with 1,25(OH)(2)D(3).

STUDY DESIGN

Newly diagnosed HNSCC patients were untreated for 3 weeks or received 3 weeks of 1,25(OH)(2)D(3) treatment befoer surgical treatment.

SUBJECTS AND METHODS

HNSCC tissue was collected by biopsy from six patients who had no prior 1,25(OH)(2)D(3) treatment and at the time of surgical treatment from six untreated patients and 11 patients who completed 1,25(OH)(2)D(3) treatment. Tissues were analyzed by immunohistochemistry for levels of CD34(+) cells and dendritic cells.

RESULTS

After 1,25(OH)(2)D(3) treatment, intratumoral levels of CD34(+) cells and levels of immature dendritic cells declined. However, levels of intratumoral mature dendritic cells increased. Clinical effects of 1,25(OH)(2)D(3) treatment are premature to analyze.

CONCLUSIONS

Treatment of HNSCC patients with 1,25(OH)(2)D(3) reduced levels of immune inhibitory CD34(+) cells while increasing maturation of dendritic cells. This supports added studies to determine the effect of 1,25(OH)(2)D(3) on intratumoral immune competence.

The Janus face of dendritic cells in cancer

On the basis of experimental models and some human data, we can assume that tumor outgrowth results from the balance between immunosurveillance (the extrinsic tumor suppressor mechanisms) and immunosubversion dictated by transformed cells and/or the corrupted surrounding microenvironment. Cancer immunosurveillance relies mainly upon conventional lymphocytes exerting either lytic or secretory functions, whereas immunosubversion results from the activity of regulatory T or suppressor myeloid cells and soluble mediators. Although specific tools to target or ablate dendritic cells (DCs) became only recently available, accumulating evidence points to the critical role of the specialized DC system in dictating most of the conventional and regulatory functions of tumor-specific T lymphocytes. Although DC can be harnessed to silence tumor development, tumors in turn can exploit DC to evade immunity. Indeed, DCs harbor defects in their differentiation and stimulatory functions in cancer-bearing hosts and can actively promote T-cell tolerance to self-tumor antigens. In this review, we will focus on the dual role of DC during tumor progression and discuss pharmacoimmunological strategies to harness DC against cancer.

The anticancer immune response: indispensable for therapeutic success?

Although the impact of tumor immunology on the clinical management of most cancers is still negligible, there is increasing evidence that anticancer immune responses may contribute to the control of cancer after conventional chemotherapy. Thus, radiotherapy and some chemotherapeutic agents, in particular anthracyclines, can induce specific immune responses that result either in immunogenic cancer cell death or in immunostimulatory side effects. This anticancer immune response then helps to eliminate residual cancer cells (those that fail to be killed by chemotherapy) or maintains micrometastases in a stage of dormancy. Based on these premises, in this Review we address the question, How may it be possible to ameliorate conventional therapies by stimulating the anticancer immune response? Moreover, we discuss the rationale of clinical trials to evaluate and eventually increase the contribution of antitumor immune responses to the therapeutic management of neoplasia.

Frontiers of cancer care in Asia-Pacific region: cancer care in Australia

Cancer has a significant impact on the Australian community. One in three men and one in four women will develop cancer by the age of 75. The estimated annual health expenditure due to cancer in 2000-1 in Australia was $2.7 billion, representing 5.5% of the country’s total healthcare expenditure. An historical overview of the national cancer control strategies in Australia is provided. In males, the five most common cancers in order of decreasing incidence are: prostate cancer, colorectal cancer, lung cancer, melanoma and lymphoma, while for Australian women, breast cancer is the most common cancer. Key epidemiologic information about these common cancers, current management issues and comprehensive national clinical practice guidelines (where available) are highlighted. Aspects of skin cancer, a particularly common cancer in the Australian environment – with a focus on melanoma – are also included.

Cancer outcomes in Australia, measured by selected outcomes, are among the best in the world. However, there is still evidence of health inequalities, especially among patients residing in regional and remote areas, the indigenous population and people from lower socio-economic classes. Limitations of current cancer care practices in Australia, including provision of oncology services, resources and other access issues, as well as suggested improvements for future cancer care, are summarised. Ongoing implementation of national and state cancer control plans and evaluation of their effectiveness will be needed to pursue the goal of optimal cancer care in Australia.