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This article endeavors to clarify the current requirements and status of regulatory approval for chemoprevention (risk reduction) drugs and discusses possible improvements to the regulatory pathway for chemoprevention. Covering a wide range of topics in as much depth as space allows, this report is written in a style to facilitate the understanding of nonscientists and to serve as a framework for informing the directions of experts engaged more deeply with this issue. Key topics we cover here are as follows: a history of definitive cancer chemoprevention trials and their influence on the evolution of regulatory assessments; a brief review of the long-standing success of pharmacologic risk reduction of cardiovascular diseases and its relevance to approval for cancer risk reduction drugs; the use and limitations of biomarkers for developing and the approval of cancer risk reduction drugs; the identification of individuals at a high(er) risk for cancer and who are appropriate candidates for risk reduction drugs; business models that should incentivize pharmaceutical industry investment in cancer risk reduction; a summary of scientific and institutional barriers to development of cancer risk reduction drugs; and a summary of major recommendations that should help facilitate the pathway to regulatory approval for pharmacologic cancer risk reduction drugs. Cancer Prev Res; 4(3); 311–23. ©2011 AACR.

Supplementary Appendices from Regulatory Approval of Cancer Risk-Reducing (Chemopreventive) Drugs: Moving What We Have Learned into the Clinic

Supplementary Figure 1 from Sheddase Activity of Tumor Necrosis Factor-α Converting Enzyme Is Increased and Prognostically Valuable in Head and Neck Cancer

Tumor necrosis factor α converting enzyme (TACE) is a sheddase overexpressed in cancers that generates cancer cell growth and survival factors, and is implicated in carcinogenesis and tumor growth. This indicates that TACE could be a potentially important cancer biomarker. Unexpectedly, TACE expression in cancer tissues does not correlate with cancer stage or invasiveness. Although TACE sheddase activity is a more direct and potentially better indicator of TACE biology and might be a better cancer biomarker than TACE expression, it has not been studied in cancer tissues. In the present study, we developed a reliable specific assay for quantification of TACE sheddase activity, investigated TACE activity and TACE protein expression in head and neck cancer (HNC) tissues, and examined the correlation of the results with HNC clinical stages and likelihood to recur. We found that HNC cell lines and tissues contained remarkably higher quantities of TACE activity and TACE protein than normal keratinocytes or oral mucosa. siRNA silencing of TACE resulted in the inhibition of release of the tumorogenic factors amphiregulin and transforming growth factor α, and tumor protective factors tumor necrosis factor receptors from HNC cells. Importantly, TACE activity, but not TACE protein expression, was significantly higher in large, T3/T4, primary tumors relative to small, T1/T2, primary tumors, and especially in primary tumors likely to recur relative to those unlikely to recur. These data show that increased TACE activity in cancer is biologically and clinically relevant, and indicate that TACE activity could be a significant biomarker of cancer prognosis. (Cancer Epidemiol Biomarkers Prev 2009;18(11):2913–22)

Supplementary Figure Legends from Sheddase Activity of Tumor Necrosis Factor-α Converting Enzyme Is Increased and Prognostically Valuable in Head and Neck Cancer

Supplementary Figure 2 from Sheddase Activity of Tumor Necrosis Factor-α Converting Enzyme Is Increased and Prognostically Valuable in Head and Neck Cancer

Supplementary Figure 3 from Sheddase Activity of Tumor Necrosis Factor-α Converting Enzyme Is Increased and Prognostically Valuable in Head and Neck Cancer

Supplementary Table 1 from Biological Significance of Prolactin in Gynecologic Cancers

There is increasing evidence that prolactin (PRL), a hormone/cytokine, plays a role in breast, prostate, and colorectal cancers via local production or accumulation. Elevated levels of serum PRL in ovarian and endometrial cancers have been reported, indicating a potential role for PRL in endometrial and ovarian carcinogenesis. In this study, we show that serum PRL levels are significantly elevated in women with a strong family history of ovarian cancer. We show dramatically increased expression of PRL receptor in ovarian and endometrial tumors as well as in endometrial hyperplasia, signifying the importance of PRL signaling in malignant and premalignant conditions. PRL mRNA was expressed in ovarian and endometrial tumors, indicating the presence of an autocrine loop. PRL potently induced proliferation in several ovarian and endometrial cancer cell lines. Binding of PRL to its receptor was followed by rapid phosphorylation of extracellular signal-regulated kinase (ERK) 1/2, mitogen-activated protein kinase/ERK kinase 1, signal transducer and activator of transcription 3, CREB, ATF-2, and p53 and activation of 37 transcription factors in ovarian and endometrial carcinoma cells. PRL also activated Ras oncogene in these cells. When human immortalized normal ovarian epithelial cells were chronically exposed to PRL, a malignant transformation occurred manifested by the acquired ability of transformed cells to form clones, grow in soft agar, and form tumors in severe combined immunodeficient-beige mice. Transformation efficiency was diminished by a Ras inhibitor, providing proof that PRL-induced transformation uses the Ras pathway. In summary, we present findings that indicate an important role for PRL in ovarian and endometrial tumorigenesis. PRL may represent a risk factor for ovarian and endometrial cancers. [Cancer Res 2009;69(12):5226–33]

The nature and local functions of tumor-infiltrating lymphocytes (TIL) in solid human tumors remain unclear, as does the precise relationship between these cells and tumor growth. Lymphocytes are often the most prominent cellular component of inflammatory infiltrates into human solid tumors. Fresh TIL, if recovered in sufficiently large numbers, were stained with labeled monoclonal antibodies to the lymphocyte surface antigens before culture and analyzed in a flow cytometer. Recent functional studies with freshly isolated and in vitro-cultured TIL from human solid tumors have failed generally to confirm that these tumors contain cytotoxic T lymphocytes specific for autologous tumor cells. Cultures of TIL were serially monitored for cytotoxicity against natural killer (NK) cell-sensitive and NK-resistant tumor targets during culture. Murine TIL cultured in vitro in the presence of recombinant interleukin-2 were claimed to be distinct from lymphokine-activated killer cells because of their specificity for autologous tumor targets, better expansion in vitro, and greater antitumor cytolytic potential.

This is the first-and only-publication available which provides the most recent information in this particular field of biomedicine. Interleukin-2 (IL-2) and IL-2 activated killer cells have been shown to have a potential in the treatment of a variety of human malignant diseases. This work comprehensively summarizes basic aspects of IL-2 as well as its clinical application, therefore making all these aspects easily accessible to the readers. Because of the clinical significance of this molecule in the treatment of cancer, the basic and clinical investigations in the IL-2 field are rapidly expanding, together with the interest of the scientific and medical community. This book is an excellent educational and teaching tool for scientists, clinicians, and students. Those who already have expertise in research in the IL-2 area will find this reference indispensible.

In a prospective randomized trial in patients with metastatic melanoma we compared two agents that had been used for metastatic melanoma intratumoral injections. Each patient had progressive metastatic disease no longer surgically controllable. Multiple metastases included satellitosis in the form of progressive nodules around the previously excised original melanoma site, and/or in-transit metastases in the form of observable tumor nodules progressing in a linear fashion toward a lymph node bearing area. As patients were receiving intratumoral injections, serially collected blood samples were tested for general immunologic reactivity and anti-melanoma reactivity. Specificity controls included breast cancer and lung cancer extracts. Additionally, as a measure of cell-mediated immunity, the patients were serially skin tested against antigens to measure general and melanoma-specific immunity. Depending on the patients’ clinical courses, we have divided the patients retrospectively into groups whose clinical courses were either better or worse than their cohorts, and determined the relationship between the immune testing and the clinical courses that the patients were experiencing as the serial testing was being conducted. Additionally, in a group of similar patients that were ‘cured for life’, we analyze their treatment in light of therapeutic attempts made by others to similarly haptenize melanoma antigens. We describe potential synergies between newly discovered melanoma therapies and intratumoral injection treatments and point out potential combination therapies that may offer the potential for enhancement of antitumor effects without increased systemic toxicity, a desirable goal now that combinations of recently acceptable immunotherapies have been associated with severe potential toxicities including death.

We have demonstrated in a randomized prospective study the superiority of intratumoral (intralesional) dinitrochlorobenzene (DNCB) compared to intratumoral (intralesional) bacillus Calmette-Guerin (BCG) in the treatment of progressive metastatic melanoma. The metastatic melanoma was in the form of satellitosis and/or in-transit metastases. We now demonstrate the ability of intralesional DNCB to permanently cure a selected group of patients with the same clinical criteria, and describe their clinical characteristics and treatment regimens. The described cured patients were followed for their remaining lifetimes, for up to 30 years, after being immunotherapeutically rendered free of metastatic cancer. They were each female, between the ages of 51 and 56 when intratumoral treatments were begun. Treatment was for progressive cutaneous and subcutaneous metastatic disease in the leg in two cases and for rapidly spreading scalp and forehead metastases in another. In each case the disease was not surgically controllable. Treatments were continued for 6 to 26 months. Subsequently the patients survived tumor free for either 18 years, dying at age 83; or for 24 years, dying at age 89; or for 30 years, dying at age 97. There has been a significant interest in recent years in immunotherapy for advanced cancer. The absence of systemic toxicity in the cured patients reported herein provides a basis for consideration of combining intratumoral treatments with current effective but systemically more toxic immunotherapeutic approaches to some metastatic cancers. Intratumoral treatments may be particularly applicable in cases of uncontrollable melanoma with cutaneous metastases, without evidence of distant spread, as in the current report.

Cancer vaccines based on antigens derived from self molecules rather than pathogens have been under basic and clinical investigations for many years. Up until very recently, they had been tested primarily in the setting of metastatic disease with the goal to engage the immune system in slowing down disease progression. Many therapeutic vaccine trials, either investigator initiated or led by pharmaceutical companies, have been completed and many are currently ongoing, following the FDA Guidance on therapeutic cancer vaccines published in 2011. In recent years, the target of cancer vaccines is being shifted to early cancer and even premalignant disease with the goal of preventing cancer. Although some issues addressed in the FDA Guidance on therapeutic vaccines apply to preventive vaccines, many do not. Here, we discuss a set of recommendations for revising the current Guidance to also cover preventive vaccines, or to include in a new Guidance dedicated specifically to vaccines for cancer prevention. Cancer Prev Res; 8(11); 1011–6. ©2015 AACR.

Pathogen-associated molecular patterns (PAMP) are stand-alone innate and adaptive immunomodulators and critical vaccine components. We present a strategy of sequential intratumoral (i.t.) and intramuscular (i.m.) injections of the stabilized dsRNA viral mimic and PAMP, polyinosinic–polycytidylic acid-polylysine-carboxymethylcellulose (poly-ICLC, Hiltonol; Oncovir). We report the first treated patient, a young man with an exceptionally advanced facial embryonal rhabdomyosarcoma with extension to the brain. After treatment, the patient showed tumor inflammation consistent with immunotherapy, followed by gradual, marked tumor regression, with extended survival. Sequential i.t. and i.m. poly-ICLC injections mimicking a viral infection can induce an effective, in situ, personalized systemic therapeutic “autovaccination” against tumor antigens of a patient. We postulate a three-step immunomodulatory process: (i) innate-immune local tumor killing induced by i.t. poly-ICLC; (ii) activation of dendritic cells with Th1 cell– and CTL–weighted priming against the released tumor antigens; and (iii) i.m. poly-ICLC maintenance of the systemic antitumor immune response via chemokine induction, facilitation of CTL killing through the induction of costimulators such as OX40, inflammasome activation, and increase in the T-effector/Treg ratio. These results support the use of certain simple and inexpensive i.t. PAMPs to favorably stimulate effective immunity against solid cancers. A phase II clinical trial testing the hypothesis presented has begun accrual (clinicaltrials.gov, NCT01984892). Cancer Immunol Res; 2(8); 720–4. ©2014 AACR.

The aim of this study was to investigate the immunological mechanisms by which synthetic methionine enkephalin (MENK) exerts therapeutic effects on tumor growth. Our findings in vivo or in vitro show that MENK treatment either in vivo or in vitro could up-regulate the percentages of CD8+T cells, induce markers of activated T cells, increased cytotoxic activity against mouse S180 tumor cells and increase secretion of IFNγ. In addition, the adoptively transferred CD8+T cells, after either in vitro or in vivo treatment with MENK, result in significantly increased survival of S180 tumor-bearing mice and significant shrinkage in tumor growth. Opioid receptors are detected on normal CD8+T cells and exposure to MENK leads to increased expression of opioid receptors. Interaction between MENK and the opioid receptors on CD8+T cells appears to be essential for the activation of CTL, since the addition of naltrexone (NTX), an opioid receptor antagonist, significantly inhibits all of the effects of MENK. The evidence obtained indicates that the MENK-induced T cell signaling is associated with a significant up-regulation of Ca2+ influx into the cytoplasm and the translocation of NFAT2 into nucleus, and these signaling effects are also inhibited by naltrexone.

The existing cell phone certification process uses a plastic model of the head called the Specific Anthropomorphic Mannequin (SAM), representing the top 10% of U.S. military recruits in 1989 and greatly underestimating the Specific Absorption Rate (SAR) for typical mobile phone users, especially children. A superior computer simulation certification process has been approved by the Federal Communications Commission (FCC) but is not employed to certify cell phones. In the United States, the FCC determines maximum allowed exposures. Many countries, especially European Union members, use the "guidelines" of International Commission on Non-Ionizing Radiation Protection (ICNIRP), a non governmental agency. Radiofrequency (RF) exposure to a head smaller than SAM will absorb a relatively higher SAR. Also, SAM uses a fluid having the average electrical properties of the head that cannot indicate differential absorption of specific brain tissue, nor absorption in children or smaller adults. The SAR for a 10-year old is up to 153% higher than the SAR for the SAM model. When electrical properties are considered, a child's head's absorption can be over two times greater, and absorption of the skull's bone marrow can be ten times greater than adults. Therefore, a new certification process is needed that incorporates different modes of use, head sizes, and tissue properties. Anatomically based models should be employed in revising safety standards for these ubiquitous modern devices and standards should be set by accountable, independent groups.

This article endeavors to clarify the current requirements and status of regulatory approval for chemoprevention (risk reduction) drugs and discusses possible improvements to the regulatory pathway for chemoprevention. Covering a wide range of topics in as much depth as space allows, this report is written in a style to facilitate the understanding of nonscientists and to serve as a framework for informing the directions of experts engaged more deeply with this issue. Key topics we cover here are as follows: a history of definitive cancer chemoprevention trials and their influence on the evolution of regulatory assessments; a brief review of the long-standing success of pharmacologic risk reduction of cardiovascular diseases and its relevance to approval for cancer risk reduction drugs; the use and limitations of biomarkers for developing and the approval of cancer risk reduction drugs; the identification of individuals at a high(er) risk for cancer and who are appropriate candidates for risk reduction drugs; business models that should incentivize pharmaceutical industry investment in cancer risk reduction; a summary of scientific and institutional barriers to development of cancer risk reduction drugs; and a summary of major recommendations that should help facilitate the pathway to regulatory approval for pharmacologic cancer risk reduction drugs. Cancer Prev Res; 4(3); 311–23. ©2011 AACR.

e21602Background: In a previous randomized prospective study in patients receiving intralesional (IL) dinitrochorobenzene (DNCB) or IL Bacillus Calmette-Guerin (BCG) we determined that serial in vi...

Purpose The National Cancer Institute (NCI) has historically evaluated the participation of underserved minorities within University of Pittsburgh Cancer Institute (UPCI) clinical trials in relation to the proportion of African Americans in the general population of the UPCI primary service area of Allegheny County (12%). This standard seemed to be unrealistically high as a result of a younger age distribution of African Americans within the county. Methods The proportions of African Americans within the following four separate county populations were compared using data from 2000 to 2004: general population; invasive cancer patients; invasive cancer patients diagnosed or treated at UPCI-affiliated facilities; and patients enrolled onto UPCI's clinical therapeutic trials. Results Although the proportion of African Americans within the general population was approximately 13%, only 9.8% of patients diagnosed with invasive cancers were African American. Approximately 9.5% of all cancer patients diagnosed or treated at UPCI facilities were African American, which is comparable to the county-wide percentage of African American cancer patients. Recruitment rate of African Americans to oncology clinical trials from within the UPCI patient population was 7.6%. The NCI benchmark did not reflect the actual invasive cancer incidence rate in African American patients. By comparing the percentage of African Americans contributing to cancer incidence with the percentage of African American cancer patients treated at research-affiliated institutions, a more appropriate benchmark was derived. Conclusion The method developed by UPCI is recommended as a useful mechanism for benchmarking recruitment of African American cancer patients to clinical therapeutic trials at other cancer centers.

The general cell-mediated immunological reactivity of patients with acute leukemia has been found to be intact, although it may be depressed by extensive disease or by chemotherapy. Patients with acute leukemia also have cellular immune reactivity against tumor associated antigens, as measured by skin tests for delayed hypersensitivity, lymphocyte stimulation, and 51Cr release cytotoxicity. Skin reactions to autologous and allogeneic crude membrane extracts of blast cells correlated with disease state, positive in many patients in remission and negative in most patients in relapse. Extracts of human lymphoid tissue culture cell lines derived from lymphomas or leukemia also gave positive reactions in patients with acute leukemia, and also in patients with lymphoma and nasopharyngeal carcinoma. The antigens detected in the skin tests with the lymphoid cell lines appear to be different from those associated with Epstein-Barr virus (EBV) and from those detected in the 51Cr release assay. Evidence is presented which suggests a complex variety of antigens on blast cells and on the cell lines. Although leukemia associated antigens were also detected by lymphocyte stimulation and by cytotoxicity assays, the results did not correlate with the skin tests nor with each other. The possible use of these assays for monitoring the chemotherapy and immunotherapy of acute leukemia patients is discussed.

The taxol resistance gene TRAG-3 was initially isolated from cancer cell lines that became resistant to taxol in vitro. TRAG-3 is a cancer germline Ag expressed by tumors of different histological types including the majority of melanoma, breast, and lung cancers. In the present study, we report that patients with stage IV melanoma and breast cancers developed spontaneous IFN-γ-producing CD4+ T cell responses against a single immunodominant and promiscuous peptide epitope from TRAG-3 presented in the context of multiple HLA-DR molecules. The TRAG-3-specific CD4+ T cells and clones were expanded in vitro and recognized not only peptide pulsed APCs but also autologous dendritic cells (DCs) loaded with the TRAG-3 protein. All stage IV melanoma patients with TRAG-3-expressing tumors developed spontaneous CD4+ T cell responses against TRAG-3, demonstrating its strong immunogenicity. None of these patients had detectable IgG Ab responses against TRAG-3. TCRβ gene usage studies of TRAG-3-specific CD4+ T cell clones from a melanoma patient and a normal donor suggested a restricted TCR repertoire in patients with TRAG-3-expressing tumors. Altogether, our data define a novel profile of spontaneous immune responses to cancer germline Ag-expressing tumors, showing that spontaneous TRAG-3-specific CD4+ T cells are directed against a single immunodominant epitope and exist independently of Ab responses. Because of its immunodominance, peptide TRAG-334–48 is of particular interest for the monitoring of spontaneous immune responses in patients with TRAG-3-expressing tumors and for the development of cancer vaccines.

In addition to their cytotoxic activities, natural killer (NK) cells can have immunoregulatory functions. We describe a distinct “helper” differentiation pathway of human CD56+CD3− NK cells into CD56+/CD83+/CCR7+/CD25+ cells that display high migratory responsiveness to lymph node (LN)–associated chemokines, high ability to produce interferon-γ upon exposure to dendritic cell (DC)- or T helper (Th) cell–related signals, and pronounced abilities to promote interleukin (IL)-12p70 production in DCs and the development of Th1 responses. This helper pathway of NK cell differentiation, which is not associated with any enhancement of cytolytic activity, is induced by IL-18, but not other NK cell–activating factors. It is blocked by prostaglandin (PG)E2, a factor that induces a similar CD83+/CCR7+/CD25+ LN-homing phenotype in maturing DCs. The current data demonstrate independent regulation of the “helper” versus “effector” pathways of NK cell differentiation and novel mechanisms of immunoregulation by IL-18 and PGE2.

Natural killer (NK) cells and dendritic cells (DCs), two important components of the immune system, can exchange bidirectional activating signals in a positive feedback. Myeloid DCs, the cell type specialised in the presentation of antigen and initiation of antigen-specific immune responses, have recently been documented to be involved in supporting innate immunity, promoting the production of cytokines and cytotoxicity of NK cells, and enhancing their tumouricidal activity. Natural interferon-producing cells/plasmacytoid DCs (IPCs/PDCs) play an additional role in NK cell activation. Reciprocally, NK cells, traditionally considered to be major innate effector cells, have also recently been shown to play immunoregulatory 'helper' functions, being able to activate DCs and to enhance their ability to produce pro-inflammatory cytokines, and to stimulate T helper (Th) 1 and cytotoxic T lymphocyte (CTL) responses of tumour-specific CD4+ and CD8+ T cells. Activated NK cells induce the maturation of myeloid DCs into stable type-1 polarised DCs (DC1), characterised by up to a 100-fold enhanced ability to produce IL-12p70 in response to subsequent interaction with Th cells. In addition, the ability of NK cells to kill tumour cells may facilitate the generation of tumour-related antigenic material, further accelerating the induction of tumour-specific immunity. DC1, induced by NK cells or by NK cell-related soluble factors, are stable, resistant to tumour-related suppressive factors, and demonstrate a strongly enhanced ability to induce Th1 and CTL responses in human in vitro and mouse in vivo models. Compared with the standard mature DCs that are used in clinical trials at present, human NK cell-induced DC1s act as superior inducers of anticancer CTL responses during in vitro sensitisation. This provides a strong rationale for the combined use of NK cells and DCs in the immunotherapy of patients with cancer and patients with chronic infections that are resistant to standard forms of treatment. Stage I/II clinical trials that are being implemented at present should allow evaluation of the immunological and clinical efficacy of combined NK-DC therapy of melanoma and other cancers.

Early detection of ovarian cancer might improve clinical outcome. Some studies have shown the role of cytokines as a new group of tumor markers for ovarian cancer. We hypothesized that a panel comprised of multiple cytokines, which individually may not show strong correlation with the disease, might provide higher diagnostic power. To evaluate the diagnostic utility of cytokine panel, we used a novel multianalyte LabMAP profiling technology that allows simultaneous measurement of multiple markers. Concentrations of 24 cytokines (cytokines/chemokines, growth, and angiogenic factors) in combination with cancer antigen-125 (CA-125), were measured in sera of 44 patients with early-stage ovarian cancer, 45 healthy women, and 37 patients with benign pelvic tumors. Six markers, i.e., interleukin (IL)-6, IL-8, epidermal growth factor (EGF), vascular endothelial growth factor (VEGF), monocyte chemoattractant protein-1 (MCP-1), and CA-125, showed significant differences in serum concentrations between ovarian cancer and control groups. Out of this group, IL-6, IL-8, VEGF, EGF, and CA-125, were used in a classification tree analysis that resulted in 84% sensitivity at 95% specificity. The receiver operator characteristic curve created using the combination of markers produced sensitivities between 90% and 100% in the area of 80% to 90% specificity, whereas the receiver operator characteristic curve for CA-125 alone resulted in sensitivities of 70% to 80%. The classification tree analysis for discrimination of benign condition from ovarian cancer used CA-125, granulocyte colony-stimulating factor (G-CSF), IL-6, EGF, and VEGF resulting in 86.5% sensitivity and 93.0% specificity. The presented data show that simultaneous testing of a panel of serum cytokines and CA-125 using LabMAP technology may present a promising approach for ovarian cancer detection.

Antibodies to several Epstein-Barr virus (EBV)-encoded enzymes are observed in patients with different EBV-associated diseases. The reason for these antibody patterns and the role these proteins might play in the pathophysiology of disease, separate from their role in virus replication, is unknown. In this series of studies, we found that purified EBV deoxyuridine triphosphate nucleotidohydrolase (dUTPase) can inhibit the replication of human peripheral blood mononuclear cells in vitro and upregulate the production of TNF-alpha, IL-1beta, IL-6, IL-8, and IL-10. It also enhanced the ability of natural killer cells to lyse target cells. The EBV dUTPase also significantly inhibited the replication of mitogen-stimulated lymphocytes and the synthesis of IFN-gamma by cells isolated from lymph nodes and spleens obtained from mice inoculated with the protein. It also produced sickness behaviors known to be induced by some of the cytokines that were studied in the in vitro experiments. These symptoms include an increase in body temperature, a decrease in body mass and in physical activity. The data provide a new perspective on how an early nonstructural EBV-encoded protein can cause immune dysregulation and produce clinical symptoms observed in patients with chronic fatigue syndrome (CFS) separate from its role in virus replication and may serve as a new approach to help identify one of the etiological agents for CFS. The data also provide additional insight into the pathophysiology of EBV infection, inflammation, and cancer.

Activated, adherent natural killer (A-NK) cells represent a distinct subpopulation of interleukin (IL)-2-stimulated NK cells, which are selectively endowed with the increased expression of integrins and ability to adhere to solid surfaces, migrate into, infiltrate, and destroy cancerous tissues. The present study defines the phenotype and functions of precursors of A-NK (pre-A-NK) cells in humans. Peripheral blood pre-A-NK cells, in contrast to the rest of NK cells, express a novel epitope of CD56 neuronal cell adhesion molecule, termed ANK-1, and increased cell-surface levels of integrins. Pre-A-NK cells also express low levels of CD56 and CD161, and some express CD162 receptor, do not express CD25 or activation markers, and are effective mediators of NK cytotoxicity. Thus, pre-A-NK cells are generally similar to CD56dim NK cells. However, pre-A-NK cells differ from the main NK cell subpopulation by having a lower expression level of CD16 and a lower ability to mediate redirected antibody-dependent, cell-mediated cytotoxicity. More importantly, pre-A-NK cells are preferentially endowed with the ability to rapidly respond to IL-2 by integrin-mediated adherence to endothelial cells, extracellular matrix, and plastic. This early, specific response of pre-A-NK cells to IL-2 is followed by their activation, vigorous proliferation, and differentiation into phenotypically and functionally similar A-NK cells. Pre-A-NK cells represent only ∼26% of peripheral blood NK cells but encompass the majority of NK cells in normal and cancerous, solid tissues. We conclude that pre-A-NK cells represent a distinct subset of resting, mature NK cells with the characteristics indicative of their ability to migrate and reside in solid tissues.

Chronic fatigue syndrome (CFS) is a serious health concern affecting over 800,000 Americans of all ages, races, socioeconomic groups and genders. The etiology and pathophysiology of CFS are unknown, yet studies have suggested an involvement of the immune system. A symposium was organized in October 2001 to explore the possibility of an association between immune dysfunction and CFS, with special emphasis on the interactions between immune dysfunction and other abnormalities noted in the neuroendocrine and autonomic nervous systems of individuals with CFS. This paper represents the consensus of the panel of experts who participated in this meeting. Data suggest that persons with CFS manifest changes in immune responses that fall outside normative ranges, but current research does not provide definitive evidence on whether these immune abnormalities are a cause or result of the illness. It has become clear that CFS cannot be understood based on single measurements of immune, endocrine, cardiovascular, or autonomic nervous system dysfunction. This panel encourages a new emphasis on multidisciplinary research into CFS.

We have shown previously that i.v. injection of interleukin-2-(IL-2) activated natural killer (A-NK) cells together with IL-2 leads to a substantial localization of the A-NK cells into most, but not all, well-established B16 lung metastases in C57BL/6 mice within 12-24 hr. We demonstrate that the morphology of the lung metastases, (loose or more compact in appearance), and their location in the lungs (on the surface or deep in the lung parenchyma) are closely tied to the infiltration-permissiveness of the metastases as well as their sensitivity to treatment with A-NK cells. Although more than 1100 A-NK cells/mm(2) were found in deep metastases with a "loose" morphology (D-L), only 534, 90 and 89 cells/mm(2) were found in surface-loose (S-L), surface-compact (S-C) and deep-compact (D-C) metastases, respectively. The best infiltrated metastases responded best to the A-NK cell therapy. Thus, metastases of the D-L phenotype became reduced by 65-90% after treatment with 2 x 10(6) A-NK cells and IL-2 (120000 IU Peg-IL-2 every 12 hr for 3 days) compared to similar lesions in animals treated with PEG-IL-2 alone. In contrast, poorly infiltrated metastases, that is lesions of the compact phenotype (D-C and S-C) as well as loose metastases on the lung surface (S-L), did not react significantly to this treatment. We conclude that adoptively transferred A-NK cells are able to eliminate even well-established metastases. The existence of metastases that are resistant to infiltration by the transferred effector cells at time of treatment might reduce the efficacy of cell-based immuno-therapeutic ventures.

Colorectal cancer is one of the most common fatal malignancies in the United States, with an incidence second only to lung cancer. The liver is the most common site of colorectal metastases and frequently the only affected organ once the primary tumor has been surgically removed. The only potentially curative treatment for metastatic colorectal cancer in the liver is surgery, although most patients are not eligible for resection. We have therefore, evaluated the therapeutic efficacy of dendritic cells (DCs) engineered to express IL-12 in a liver metastasis model. Direct administration of DCs into the portal vein significantly inhibited the growth of established MC38 colon carcinoma in the liver in C57BL/6 mice. This effect was accompanied by an intratumoral accumulation of CD4+, CD8+, and NLDC-145+ immune effector cells, and also resulted in a systemic immune response as determined by enhanced production of IFN-gamma by T lymphocytes isolated from both spleen and draining lymph nodes. Evaluation of homing of Cy3-labeled DCs following the portal vein injection confirmed their distribution in the liver and lymphoid tissue. Thus, a local delivery of DCs transduced with the IL-12 gene can not only inhibit colorectal tumor growth in vivo but also mount systemic antitumor immune responses. This approach is likely to improve the outcome of immunotherapy for metastatic colorectal cancer since high numbers of tumor-associated DCs positively correlate with a more favorable prognosis. Simultaneous local gene therapy with IL-12 will further improve clinical efficacy without placing the patient at risk for systemic toxicity.

Natural killer (NK) cells were first identified for their ability to kill tumor cells of different origins. They were subsequently found to be able to kill some normal cells, especially those infected by certain viruses. Natural killer cells are a distinct lymphocytic population, with the morphology of large granular lymphocytes, and they lack surface Ig or T-cell markers. Natural killer cytotoxicity is enhanced in vitro in the presence of cytokines such as interleukin-2 and interferon-alpha. However, when used in immunotherapy, these cytokines have not consistently augmented NK activity or shown antitumor effects. One explanation for this divergence is that NK cell activity is suppressed in tumor tissues by various factors, including reactive oxygen species produced by infiltrating monocytes and macrophages. Agents that inhibit the generation of reactive oxygen species, such as histamine, may abrogate the suppression exerted on NK cells by monocytes/macrophages, therefore offering potential therapeutic benefit as immunoadjuvants.