Current Cancer Drug Targets - Volume 7, Issue 1, 2007

Since it has become clear that tumor can be recognized and eliminated by the host immune system, two main questions have confronted researchers and physicians: why the immune system does not prevent tumor progression, and how to manipulate the immune system to achieve tumor eradication. The last 20 years have brought a clear realization that one of the major mechanisms of tumor escape and one of the Read More

Despite recent advances in vaccine technology, vaccines designed to elicit T cell-based anti-tumor immunity have only achieved partial success in the clinic. The underlying reason probably stems in part from the ability of tumors to repress cognate T cell responses, which appears to operate at two separate levels. In some cases, tumors engage a variety of immunosuppressive pathways that inhibit primed effector T cells from fu Read More

The immune system is an important defense mechanism against cancer and is often dysfunctional in patients with malignancies. The central regulator of the anti-cancer adaptive immune response is the T lymphocyte. T lymphocyte activation requires the completion of a carefully orchestrated series of specific steps that can be preempted or disrupted by any number of critical events. Particularly important is the p Read More

The extrahepatic enzyme indoleamine 2,3-dioxygenase (IDO) catalyzes tryptophan degradation in the first and rate-limiting step towards biosynthesis of the central metabolic co-factor nicotinamide adenine dinucleotide (NAD). While this pathway has been known for decades, the actual physiological role for IDO in mammals remained obscure, because (i.) most cell types do not express the downstream enzymes in Read More

The spontaneous interaction between tumor cells and the immune system has been shown to result in reciprocal changes leading to a less immunogenic tumor and immune cells less capable or unable to mount an effective response against a growing malignancy. Although several mechanisms have been proposed to account for the ability of tumor cells to render immune cells less efficient, one that has gained parti Read More

Central to the normal function of the immune system is its ability to distinguish between self and non-self since failure to do so could provoke the onset of autoimmune disease. To avoid this possibility, the immune system employs several processes that include, negative selection, peripheral tolerance, and limiting DC antigen priming of naïve T cells to the lymph nodes. Naïve T cells must receive two independent signals from t Read More

One of the major mechanisms of tumor escape is the inability of antigen presenting cells (APC), and specifically the most potent APC dendritic cells (DC), to induce potent antitumor immune response. The defects in APC are caused by the variety of tumor-derived factors. In this review we will discuss recent findings which indicate that the members of the family of signal transducers and activators of transcription (STATs), and Read More

The greatest risk factor for the development of cervical and other cancers that have been linked to the human papillomavirus (HPV) family is the persistence of the virus. To persist for the decades required to develop HPV-related cancers, the virus must escape host immunity. HPV is a simple DNA virus that has evolved to escape immune attack by a combination of stealth and interference. This review focuses on the mechanis Read More

Constitutive activation of the Signal Transducers and Activators of Transcription 3 (Stat3) meditated signaling pathway is very important for cell growth and survival. Compelling evidence from mechanistic studies with antisense, RNA interference (RNAi), peptides, and small molecular inhibitors indicate that blocking Stat3 signaling can lead to successful suppression of tumor cell growth and apoptosis. Thus, Stat3 is an a Read More

Ovarian cancer presents as disseminated disease in the majority of cases. Tumor metastasis to the peritoneal and/or pleural cavity is evident in two-thirds of cases at diagnosis and relapse is most often detected at this anatomic site. Despite the fact that the primary tumor is amenable to surgical removal in the majority of cases, ovarian cancer research, including the evaluation of therapeutic targets, has concentrated on Read More