Skin cancer screening: recommendations for data-driven screening guidelines and a review of the US Preventive Services Task Force controversy

Melanoma is usually apparent on the skin and readily detected by trained medical providers using a routine total body skin examination, yet this malignancy is responsible for the majority of skin cancer-related deaths. Currently, there is no national consensus on skin cancer screening in the USA, but dermatologists and primary care providers are routinely confronted with making the decision about when to recommend total body skin examinations and at what interval. The objectives of this paper are: to propose rational, risk-based, data-driven guidelines commensurate with the US Preventive Services Task Force screening guidelines for other disorders; to compare our proposed guidelines to recommendations made by other national and international organizations; and to review the US Preventive Services Task Force's 2016 Draft Recommendation Statement on skin cancer screening.

RANTES secretion by gene-modified tumor cells results in loss of tumorigenicity in vivo: role of immune cell subpopulations

An immunogenic murine fibrosarcoma cell line was genetically modified to express and produce the human RANTES chemokine stably. In in vitro chemotaxis assays purified recombinant human RANTES as well as human RANTES secreted by the modified murine tumor cells were strongly chemoattractant for mouse CD8+ /Thy-1+ tumor-infiltrating lymphocytes (TIL). RANTES production did not alter the growth of these cytokine gene-modified tumor cells in vitro, but injection of RANTES-secreting cells resulted in the abolition of the ability of those cells to form solid tumors in vivo. The growth of tumors could be restored by co-administration of monoclonal antibodies that inhibit the function of various subsets of immune cells. For example, depletion of CD8+ T cells by antibody administration resulted in complete restoration of solid tumor formation by RANTES-secreting cells, whereas depletion of the CD4+ T cell population resulted in a partial restoration of tumor formation. Additionally, administration of an anti-CR3 monoclonal antibody known to inhibit the in vivo migration of macrophages also completely restored the tumorigenicity of RANTES-secreting fibrosarcoma cells. Thus, the human RANTES chemokine can abolish tumorigenicity of an immunogenic fibrosarcoma in an in vivo murine model, and this process is mediated by various subpopulations of immune effector cells.

Differences in the bioactivity of recombinant human TNF, LT, and T-cell-derived LT-3 on transformed cells in vitro and the Meth A tumor growing in BALB/c mice

Cytolytic human T cells and the continuous human T cell line YM 1.2 can secrete a lymphotoxin (LT) form, termed LT-3, when stimulated in vitro. LT-3 is immunologically related to, but functionally distinct from, both alpha LT and tumor necrosis factor (TNF). Purified, native LT-3 and recombinant human LT and TNF were tested for their ability to destroy a panel of primary and continuous cell lines in vitro and cause necrosis of 8- to 9-day cutaneous Meth A tumors growing in BALB/c mice. LT-3 is more effective than either LT or TNF in inducing destruction of continuous cell lines in vitro. LT-3 induces destruction of cell lines that are resistant to both TNF and LT, and much less LT-3 is required to destroy cells that are LT and/or TNF sensitive. In contrast, none of these mediators had any measurable negative effects when tested on primary human fibroblasts. Additional studies revealed that LT-3 is also active in vivo and can cause necrosis of cutaneous Meth A tumors when administered intraperitoneally or intratumorally on BALB/c mice. LT-3 induces more rapid, consistent, and complete tumor necrosis than equivalent doses of either LT or TNF.