Editorial:Hot Topic: [Anti-Cancer Drugs(Executive Editor: Elke Bergmann-Leitner)]

While cancer remains a major killer in the developed world, a broad spectrum of novel and exciting approaches are being developed and tested. This issue of Current Pharmaceutical Design “Anti-cancer drugs” will once again highlight several of these developments and present an up-to date overview. Among the molecules used or targeted in the research described are both novel compounds with promising activity such as the Prodigiosins, and familiar molecules whose function and involvement in tumorigenesis have only recently been appreciated, such as the key role that chemokines play in metastasis. A common theme, however, is the increasing selectivity of the pathways that are being targeted resulting in more and more selective anti-tumor activity and ever decreasing off-target effects. Another highly encouraging aspect is the effectiveness of some approaches, such as the use of novel NF-κB inhibitors, on tumors which have developed resistance to a broad spectrum of conventional chemotherapeutics or immunotherapy. Pandey et al. review the bacterial pigment family of Prodigiosins, which contain compounds with strong antimicrobial, anti-malarial and anti-neoplastic activity [1]. While the mode of action is not completely defined, several signaling pathways seem to be involved in the mediation of anti-cancer activities and the authors summarize the latest findings in regards to the mechanisms. Wu et al. first provide us with an overview over chemokines and their receptors and then report on the latest advances in targeting chemokine receptors for cancer therapy [2] as the involvement of these molecules in metastasis is slowly being unveiled. Another novel set of weapons in the fight against cancer cells are receptor tyrosine kinase (RTK) inhibitors which are reviewed by Sharma et al. [3]. The rationale behind this strategy is that RTKs mediate cell growth by various pathways and are often involved in the initiation and progression of tumors. Inhibitors of these enzymes have shown to revert the malignant phenotype and thus have validated this treatment approach. Inhibitors of RTK can be various classes of molecules, some derived from natural ingredients. Others can be engineered in the form of monoclonal antibodies specific for a particular RTK.