Stages Of Cancer Development Research Articles

Prostate stromal cells produce CXCL-1, CXCL-2, CXCL-3 and IL-8 in response to epithelia-secreted IL-1

It is well accepted that tumor microenvironment is essential for tumor cells survival, cancer progression and metastasis. However, the mechanisms by which tumor cells interact with their surrounding at early stages of cancer development are largely unidentified. The aim of this study was to identify specific molecules involved in stromal-epithelial interactions that might contribute to early stages of prostate tumor formation. Here, we show that conditioned medium (CM) from immortalized non-transformed prostate epithelial cells stimulated immortalized prostate stromal cells to express cancer-related molecules. CM obtained from epithelial cells triggered stromal cells to express and secrete CXCL-1, CXCL-2, CXCL-3 and interleukin (IL)-8 chemokines. This effect was predominantly mediated by the cytokines of the IL-1 family secreted by the epithelial cells. Thus, prostate epithelial cells induced the secretion of proinflammatory and cancer-promoting chemokines by prostate stromal cells. Such interactions might contribute to prostatic inflammation and progression at early stages of prostate cancer formation.

Impaired Replication Stress Response in Cells from Immunodeficiency Patients Carrying Cernunnos/XLF Mutations

Non-Homologous End Joining (NHEJ) is one of the two major pathways of DNA Double Strand Breaks (DSBs) repair. Mutations in human NHEJ genes can lead to immunodeficiency due to its role in V(D)J recombination in the immune system. In addition, most patients carrying mutations in NHEJ genes display developmental anomalies which are likely the result of a general defect in repair of endogenously induced DSBs such as those arising during normal DNA replication. Cernunnos/XLF is a recently identified NHEJ gene which is mutated in immunodeficiency with microcephaly patients. Here we aimed to investigate whether Cernunnos/XLF mutations disrupt the ability of patient cells to respond to replication stress conditions. Our results demonstrate that Cernunnos/XLF mutated cells and cells downregulated for Cernunnos/XLF have increased sensitivity to conditions which perturb DNA replication. In addition, under replication stress, these cells exhibit impaired DSB repair and increased accumulation of cells in G2/M. Moreover Cernunnos/XLF mutated and down regulated cells display greater chromosomal instability, particularly at fragile sites, under replication stress conditions. These results provide evidence for the role of Cernunnos/XLF in repair of DSBs and maintenance of genomic stability under replication stress conditions. This is the first study of a NHEJ syndrome showing association with impaired cellular response to replication stress conditions. These findings may be related to the clinical features in these patients which are not due to the V(D)J recombination defect. Additionally, in light of the emerging important role of replication stress in the early stages of cancer development, our findings may provide a mechanism for the role of NHEJ in preventing tumorigenesis.

Interleukin-10 G-1082A and C-819T Polymorphisms as Possible Molecular Markers of Urothelial Bladder Cancer

Interleukin-10 (IL-10) is an immunosuppressive cytokine that may promote tumor growth and metastasis in later stages of cancer development. DNA sequence variations in IL-10 gene may lead to altered production and/or activity, and this can modulate an individual's susceptibility to urothelial bladder cancer (UBC). To test this hypothesis, we investigated the association of rs 1800896 and rs 3021097 polymorphisms in IL-10 gene and their haplotypes with the risk of UBC in a Northern Indian population. We analyzed two single nucleotide polymorphisms of IL-10 gene at G-1082A (rs 1800896) and C-819T (rs 3021097) in 214 histologically confirmed UBC patients and 385 matched controls by allele-specific polymerase chain reaction (AS-PCR). IL-10 C-819T CT, TT genotypes and T carriers (CT + TT) had significant association with UBC susceptibility (OR 1.75, 95% CI 1.09-2.80; OR 1.81, 95% CI 1.09-3.01 and OR 1.77, 95% CI 1.14-2.75, respectively). Similarly, GA, AA genotypes and A carriers (G-1082A) demonstrated increased risk for UBC (OR 1.91, 95% CI 1.04-3.50; OR 2.01, 95% CI 1.08-3.74 and OR 1.95, 95% CI 1.09-3.50, respectively). TT (C-819T) and T carriers showed protective association with high-risk tumors; (OR 0.34, 95% CI 0.13-0.88 and OR 0.41, 95% CI 0.17-0.97, respectively). We did not observe any association of IL-10 polymorphisms with smoking habits and UBC risk. The study suggested that the low-producing genotypes of IL-10 (C-819T and G-1082A) polymorphisms are associated with increased UBC risk. Individuals with (C-819T) TT genotype and T carriers, however, showed a protective association with high-risk tumors. Our data suggest that IL-10 G-1082A and C-819T polymorphisms may be used as a molecular marker of urothelial bladder cancer.

A heteroplasmic, not homoplasmic, mitochondrial DNA mutation promotes tumorigenesis via alteration in reactive oxygen species generation and apoptosis

Mitochondrial alteration has been long proposed to play a major role in tumorigenesis. Recently, mitochondrial DNA (mtDNA) mutations have been found in a variety of cancer cells. In this study, we examined the contribution of mtDNA mutation and mitochondrial dysfunction in tumorigenesis first using human cell lines carrying a frame-shift at NADH dehydrogenase (respiratory complex I) subunit 5 gene (ND5); the same homoplasmic mutation was also identified in a human colorectal cancer cell line earlier. With increasing mutant ND5 mtDNA content, respiratory function including oxygen consumption and ATP generation through oxidative phosphorylation declined progressively, while lactate production and dependence on glucose increased. Interestingly, the reactive oxygen species (ROS) levels and apoptosis exhibited antagonistic pleiotropy associated with mitochondrial defects. Furthermore, the anchorage-dependence phenotype and tumor-forming capacity of cells carrying wild-type and mutant mtDNA were tested by growth assay in soft agar and subcutaneous implantation of the cells in nude mice. Surprisingly, the cell line carrying the heteroplasmic ND5 mtDNA mutation showed significantly enhanced tumor growth, while cells with homoplasmic form of the same mutation inhibited tumor formation. Similar results were obtained from the analysis of a series of mouse cell lines carrying a nonsense mutation at ND5 gene. Our results indicate that the mtDNA mutations might play an important role in the early stage of cancer development, possibly through alteration of ROS generation and apoptosis.

Reflectance optical tomography in epithelial tissues

We seek to reconstruct an absorbing obstacle contained within the top layer of a two-layer halfspace from boundary measurements of backscattered light. This problem is a model for detecting early stages of cancer development in thin epithelial tissues that reside on top of thick stromal tissues. For the direct obstacle scattering problem, we use a combination of the discrete ordinate method with a pseudo-spectral/finite difference method to compute numerical solutions. For the inverse obstacle scattering problem, we use the first Born approximation to compute an explicit solution for a thin obstacle. Using that solution, we seek a numerical fit to the data to determine the depth of the obstacle. Using that recovered depth, we then seek a reconstruction of its transverse spatial distribution.

Androgen-independent prostate cancer cells acquire the complete steroidogenic potential of synthesizing testosterone from cholesterol

The proliferation and differentiation of normal prostate epithelial cells depends upon the action of androgens produced by the testis. Prostate cancers retain the ability to respond to androgens in the initial stages of cancer development, but progressively become independent of exogenous androgens in advanced stages of the disease while maintaining the expression of functional androgen receptor (AR). In the present study, we have determined the potential of prostate cancer cells to synthesize androgens from cholesterol which may be involved in intracrine regulation of AR in advanced stages of the disease. Established androgen-independent prostate cancer cell lines, PC3 and DU145 cells, expressed mRNA and proteins for scavenger receptor type B1 (SRB1), steroidogenic acute regulatory (StAR) protein, cytochrome P450 cholesterol side chain cleavage (P450scc), 3beta-hydroxysteroid dehydrogenase (3beta-HSD) and other enzymes involved in androgen biosynthesis. Expression of all these proteins and enzymes was significantly higher in the androgen-independent derivative of LNCaP prostate cancer cells (C81) than in the androgen-dependent cell line (C33). In serum-free cultures, the androgen-independent C81 cells secreted approximately 5-fold higher testosterone than C33 cells as determined in the conditioned media by immunoassays. These cells could also directly convert radioactive cholesterol into testosterone which was identified by thin layer chromatography. These results for the first time show that prostate cancer cells in advanced stages of the disease could synthesize androgens from cholesterol and hence are not dependent upon testicular and/or adrenal androgens.

Reply

We are grateful to Drs Grugan and Nakagawa for their careful review of our recent study (Cancer Cell 2008;13:441–453) and appreciate their detailed discussion. However, we would like to clarify a few points regarding the role of the primary tumor and the evolutionary model of cancer progression. First, we did not state “that the primary tumor cannot be used to estimate prognosis.” Primary tumors can and have often been used to predict prognosis. As mentioned by Drs Grugan and Nakagawa, predictive gene expression signatures have been identified as well as informative protein markers. However, a closer look into how these signatures are usually obtained and on the genes that the signatures comprise, provides evidence that the signatures do not describe the molecular mechanisms that are active during early systemic progression. Linking outcome with gene expression results in lists of genes that carry prognostic information, but do not define the functional processes involved in metastasis. Not surprisingly, most if not all signatures are proliferation signatures (Nat Rev Cancer 2007;7:545–553). Proliferation certainly is fundamental for metastasis, but mechanisms involved might differ between clones and depend, for example, on the microenvironment (availability of growth factors, cellular signals, oxygen, nutrients). Our data suggest that different genomes are selected during early metastasis. High proliferation at the primary site is likely to support the generation of variant cells fit to survive and thrive at distant sites. Therefore, our findings do not contradict the suitability of primary tumors to predict outcome. However, they do challenge the contention that therapy targets that are identified in primary tumors will necessarily be present and essential in disseminated cancer cells. Thus, we deem primary tumors to be less reliable surrogate markers for the selection of adjuvant therapies. Molecular processes and thereby molecular targets involved in dissemination, (ectopic) survival, and colonization apparently differ for cells being selected at the primary site and at distant sites. The divergent genetic aberrations might reflect selection processes during homing but also during survival and early colonization. Second, Drs Grugan and Nakagawa might have misunderstood our paper on early dissemination of breast cancer (Cancer Cell 2008;13:58–68). We did not observe an increase of DTCs in bone marrow of breast cancer patients with larger tumor size. In contrast, we were puzzled by the lack of such a significant association in >600 patients. Although cell numbers in primary tumors increase several hundred fold from T1 stage to stage T3/4, no such increase is observed for DTCs in bone marrow. Thus, if also true for other cancers, this finding might suggest that indeed sessile cells are selected within a colony (primary tumor or metastasis) and that dissemination peaks transiently at a certain stage of cancer development. Again, this would fit into an evolutionary model of cancer progression and would make a more careful analysis of early systemic cancer necessary. Primary tumors and metastases are important for our understanding of cancer because they arose from clones that have successfully established colonies. However, varying selection pressures (such as those exerted by different anatomic sites or adjuvant therapies) favor different clones. Thus, searching the Achilles' heel of metastatic precursor cells to prevent metastases may benefit from the direct analysis of disseminated cancer cells. HER2 Amplification in Micrometastatic Esophageal Cancer Cells Predicts PrognosisGastroenterologyVol. 135Issue 3PreviewStoecklein NH, Hosch SB, Bezler M, et al. (Department of Pathology, University of Regensburg, Regensburg, Germany). Direct genetic analysis of single disseminated cancer cells for prediction of outcome and therapy selection in esophageal cancer. Cancer Cell 2008;13:441–453. Full-Text PDF

When flies and mice develop cancer

![][1] The Spanish National Cancer Institute (CNIO) Meeting on Development and Cancer took place between 4 and 6 February 2008 in Madrid, Spain, and was organized by K. Basler, G. Morata, E. Moreno and M. Torres. ![][2] Developmental biologists rightly argue that genes regulating developmental pathways are reiterated in cancer development. At the recent Spanish National Cancer Institute (CNIO) Meeting on Development and Cancer, novel concepts and processes that are considered to be common to both embryonic and cancer development were discussed. It is worth pointing out that tumour formation should be considered to be a form of aberrant organ development, in which many developmental pathways that control proliferation, differentiation and growth or morphogenesis are affected. This report is structured in three parts, describing the work presented at the meeting according to the stages of tumour development to which it pertains. First, the normal behaviour of cell populations that are the targets of transformation, in particular adult stem cells and the pathways that regulate their behaviour. Second, processes that occur at the early stages of cancer development before morphological malformations are detectable, in particular the process that is best known from studies in flies as ‘cell competition’. Third, developmental processes and pathways that are active in the growing tumour—which we consider to be an extrinsic organ—for example, the recruitment of blood vessels or the role of morphogens in controlling the size and shape of tumours, and the progression from hyperplasia to invasive tumours (Fig 1). Figure 1. Tumour development and genes involved in the different stages. Schematic representation of how stem cells (A) , by acquiring a mutation through cell competition ( B ) and by the selection of additional mutations, can give rise to the ‘tumour organ’ ( C ). The genes involved in these processes are listed on the right‐hand side, and most of them … [1]: /embed/graphic-1.gif [2]: /embed/graphic-2.gif

Functional domains of CCN1 (Cyr61) regulate breast cancer progression

CCN1 plays diverse roles in cellular proliferation, survival, migration and angiogenesis. We determined the relationship between CCN1 protein expression and clinical factors that are important for the classification of breast cancer. CCN1 contains four functional domains; the contribution of each of the structural domains to the biological properties of CCN1 in breast cancer was investigated. We performed immunohistochemistry for CCN1 on a breast cancer tissue array, and conducted a detailed statistical analysis on the relationship between CCN1 protein expression and clinical factors that are important for the classification of breast cancer. The structure-function relationship was examined using four mutant constructs in which one of the modules (DM1-DM4) had been deleted. MCF-7 breast cancer cells were stably transfected with these constructs and their biological activity was tested in comparison to full-length CCN1. Staining of CCN1 in tumors was positively correlated with AJCC disease stage. A strong association also was found between lymph node involvement and high CCN1 expression in patients with invasive breast cancer; there was a significant increase in the breast cancer expression of CCN1 in patients with positive lymph nodes (P=0.004), and the levels of CCN1 correlated with the number of positive lymph nodes (P=0.0006). Deletion of module 4 rendered CCN1 unable to either bind heparin or associate with the extracellular matrix. Furthermore, MCF-7/DM4 cells demonstrated reduced cell spreading, migration and proliferation, indicating that module 4 of the protein is important for its ability to promote these activities. These findings indicate that CCN1 is involved throughout the clinical progression of breast cancer to an invasive phenotype. The multimodular structure of CCN1 enables it to fulfill multiple functions that may contribute to the different stages of cancer development, raising the prospect that specific regions of CCN1 could be targeted for therapeutic benefit to inhibit particular aspects of malignancy in breast cancer.

Interferon Regulatory Factors IRF5 and IRF7 Inhibit Growth and Induce Senescence in Immortal Li-Fraumeni Fibroblasts

Cellular immortalization is one of the prerequisite steps in carcinogenesis. By gene expression profiling, we have found that genes in the interferon (IFN) pathway were dysregulated during the spontaneous cellular immortalization of fibroblasts from Li-Fraumeni syndrome (LFS) patients with germ-line mutations in p53. IFN signaling pathway genes were down-regulated by epigenetic silencing during immortalization, and some of these same IFN-regulated genes were activated during replicative senescence. Bisulfite sequencing of the promoter regions of two IFN regulatory transcription factors (IRF5 and IRF7) revealed that IRF7, but not IRF5, was epigenetically silenced by methylation of CpG islands in immortal LFS cells. The induction of IRF7 gene by IFNalpha in immortal LFS cells was potentiated by pretreatment with the demethylation agent 5-aza-2'-deoxycytidine. Overexpression of IRF5 and IRF7 revealed that they can act either alone or in tandem to activate other IFN-regulated genes. In addition, they serve to inhibit the proliferation rate and induce a senescence-related phenotype in immortal LFS cells. Furthermore, polyinosinic:polycytidylic acid treatment of the IRF-overexpressing cells showed a more rapid induction of several IFN-regulated genes. We conclude that the epigenetic inactivation of the IFN pathway plays a critical role in cellular immortalization, and the reactivation of IFN-regulated genes by transcription factors IRF5 and/or IRF7 is sufficient to induce cellular senescence. The IFN pathway may provide valuable molecular targets for therapeutic interventions at early stages of cancer development.

Orchestration of the S-phase and DNA damage checkpoint pathways by replication forks from early origins

The S-phase checkpoint activated at replication forks coordinates DNA replication when forks stall because of DNA damage or low deoxyribonucleotide triphosphate pools. We explore the involvement of replication forks in coordinating the S-phase checkpoint using dun1Δ cells that have a defect in the number of stalled forks formed from early origins and are dependent on the DNA damage Chk1p pathway for survival when replication is stalled. We show that providing additional origins activated in early S phase and establishing a paused fork at a replication fork pause site restores S-phase checkpoint signaling to chk1Δ dun1Δ cells and relieves the reliance on the DNA damage checkpoint pathway. Origin licensing and activation are controlled by the cyclin–Cdk complexes. Thus, oncogene-mediated deregulation of cyclins in the early stages of cancer development could contribute to genomic instability through a deficiency in the forks required to establish the S-phase checkpoint.

The Rho-activating CNF1 toxin from pathogenic E. coli: A risk factor for human cancer development?

Nowadays, there is increasing evidence that some pathogenic bacteria can contribute to specific stages of cancer development. The concept that bacterial infection could be involved in carcinogenesis acquired a widespread interest with the discovery that H. pylori is able to establish chronic infections in the stomach and that this infection is associated with an increased risk of gastric adenocarcinoma and mucosa associated lymphoid tissue lymphoma. Chronic infections triggered by bacteria can facilitate tumor initiation or progression since, during the course of infection, normal cell functions can come under the control of pathogen factors that directly manipulate the host regulatory pathways and the inflammatory reactions.Renowned publications have recently corroborated the molecular mechanisms that link bacterial infections, inflammation and cancer, indicating certain strains of Escherichia coli as a risk factor for patients with colon cancer. E. coli is a normal inhabitant of the human intestine that becomes highly pathogenic following the acquisition of virulence factors, including a protein toxin named cytotoxic necrotizing factor 1 (CNF1). This toxin permanently activates the small GTP-binding proteins belonging to the Rho family, thus promoting a prominent polymerization of the actin cytoskeleton as well as a number of cellular responses, including changes in protein expression and functional modification of the cell physiology. CNF1 is receiving an increasing attention as a putative factor involved in transformation because of its ability to: (i) induce COX2 expression, an immediate-early gene over-expressed in some type of cancers; (ii) induce a long-lasting activation of the transcription factor NF-kB, a largely accepted marker of tumor cells; (iii) protect epithelial cells from apoptosis; (iv) ensue the release of pro-inflammatory cytokines in epithelial and endothelial cells; and (v) promote cellular motility. As cancer may arise through dysfunction of the same regulatory systems, it seems likely that CNF1-producing E. coli infections can contribute to tumor development.This review focuses on the aspects of CNF1 activity linked to cell transformation with the aim of contributing to the identification of a possible carcinogenic agent from the microbial world.

In vivo multiphoton microscopy of NADH and FAD redox states, fluorescence lifetimes, and cellular morphology in precancerous epithelia

Metabolic imaging of the relative amounts of reduced NADH and FAD and the microenvironment of these metabolic electron carriers can be used to noninvasively monitor changes in metabolism, which is one of the hallmarks of carcinogenesis. This study combines cellular redox ratio, NADH and FAD lifetime, and subcellular morphology imaging in three dimensions to identify intrinsic sources of metabolic and structural contrast in vivo at the earliest stages of cancer development. There was a significant (P < 0.05) increase in the nuclear to cytoplasmic ratio (NCR) with depth within the epithelium in normal tissues; however, there was no significant change in NCR with depth in precancerous tissues. The redox ratio significantly decreased in the less differentiated basal epithelial cells compared with the more mature cells in the superficial layer of the normal stratified squamous epithelium, indicating an increase in metabolic activity in cells with increased NCR. However, the redox ratio was not significantly different between the superficial and basal cells in precancerous tissues. A significant decrease was observed in the contribution and lifetime of protein-bound NADH (averaged over the entire epithelium) in both low- and high-grade epithelial precancers compared with normal epithelial tissues. In addition, a significant increase in the protein-bound FAD lifetime and a decrease in the contribution of protein-bound FAD are observed in high-grade precancers only. Increased intracellular variability in the redox ratio, NADH, and FAD fluorescence lifetimes were observed in precancerous cells compared with normal cells.

Declining cellular fitness with age promotes cancer initiation by selecting for adaptive oncogenic mutations

Age is the single most important prognostic factor in the development of many cancers. The major reason for this age-dependence is thought to be the progressive accumulation of oncogenic mutations and epigenetic changes. Similarly, mutagens are thought to be carcinogenic primarily by engendering oncogenic mutations. Yet while the accumulation of heritable somatic changes is expected to augment the incidence of oncogenic mutations, a major effect of increased mutation load is reduced fitness. We propose that the fitness of progenitor cell compartments substantially impacts on the selective advantage conferred by particular mutations. We hypothesize that reduced cellular fitness within aged stem cell pools can select for adaptive oncogenic events and thereby promote the initiation of cancer. Thus, certain oncogenic mutations may be adaptive within aged but not young stem cell pools. We further argue that accumulating genetic alterations with age or mutagen exposure might promote cancer not only by causing oncogenic hits within cells but also by leading to eventual reduction in stem cell fitness, which then selects for oncogenic events. Therefore, initial stages of cancer development may not be limited by the incidence of initiating oncogenic changes, but instead by contexts of reduced cellular fitness that select for these changes.

The 2G allele of promoter region of Matrix metalloproteinase-1 as an essential pre-condition for the early onset of oral squamous cell carcinoma

BackgroundMatrix metalloproteinase (MMP) is known to be involved in the initial and progressive stages of cancer development, and in the aggressive phenotypes of cancer. This study examines the association of single nucleotide polymorphisms in promoter regions of MMP-1 and MMP-3 with susceptibility to oral squamous cell carcinoma (OSCC).MethodsWe compared 170 Japanese OSCC cases and 164 healthy controls for genotypes of MMP-1 and MMP-3.ResultsThe frequency of the MMP-1 2G allele was higher and that of the 1G homozygote was lower in the OSCC cases (p = 0.034). A multivariate logistic regression analysis revealed that subjects who were 45 years old or older had a significantly increased (2.47-fold) risk of OSCC (95%CI 1.47–4.14, p = 0.0006), and those carrying the MMP-1 2G allele had a 2.30-fold risk (95%CI 1.15–4.58, p = 0.018), indicating independent involvement of these factors in OSCC. One of the key discoveries of this research is the apparent reduction of the MMP-1 1G/1G and 1G/2G genotype distributions among the early onset OSCC cases under the ages of 45 years. It should be noted that the tongue was the primary site in 86.2% of these early onset cases. This could suggest the specific carcinogenic mechanisms, i.e. specific carcinogenic stimulations and/or genetic factors in the tongue.ConclusionSince the 2G allele is a majority of the MMP-1 genotype in the general population, it seems to act as a genetic pre-condition in OSCC development. However this report suggests a crucial impact of the MMP-1 2G allele in the early onset OSCC.

Somatic acquisition of TGFBR1*6A by epithelial and stromal cells during head and neck and colon cancer development

TGFBR1*6A is a common hypomorphic variant of the type I transforming growth factor (TGF)-beta receptor (TGFBR1), which transduces TGF-beta growth inhibitory signals less effectively than TGFBR1. Recent studies suggest that TGFBR1*6A confers a selective growth advantage to both normal appearing and cancerous epithelial cells in the presence of TGF-beta. We have previously shown that TGFBR1*6A is somatically acquired in head and neck and colon cancer (10). Using microdissected tissues, we show that TGFBR1*6A is somatically acquired by stromal and epithelial cells adjacent to colorectal and head and neck tumors. Somatic acquisition of the TGFBR1*6A allele is not accompanied by acquisition of other tumor-specific mutations. Furthermore, lymphocytes located within the stroma or the normal appearing epithelium do not have evidence of TGFBR1*6A acquisition. The highest TGFBR1*6A/TGFBR1 allelic ratio is observed at the tumor's edge, and traces of TGFBR1*6A are detected as far as 2 cm away from the tumor, which is suggestive of centrifugal spread of cells that harbor TGFBR1*6A. Assessment of CDH1 and CDH2 expression does not indicate epithelial-mesenchymal transformation. The results suggest that TGFBR1*6A somatic acquisition is a critical event in the early stages of cancer development that is associated with field cancerization. They also represent the first human report of somatically acquired altered stromal TGF-beta signaling during oncogenesis and the first report of a concordant mutation in the stromal and epithelial compartments in colon cancer.

The evolving concept of tumor microenvironments

The role of the microenvironment in cancer development is being increasingly appreciated. This paper will review data that highlight an emerging distinction between two different entities: the microenvironment that altered/preneoplastic/neoplastic cells find in the tissue where they reside, and the peculiar microenvironment inside the focal lesion (tumor) that these cells contribute to create. While alteration in the tissue environment can contribute to the selective clonal expansion of altered cells to form focal proliferative lesions, the atypical, non-integrated growth pattern that defines such focal lesions leads to the appearance of what is correctly referred to as the tumor microenvironment. The latter represents a new and unique biological milieu, characterized by hypoxia, acidosis and other biochemical and metabolic alterations, including genetic instability, that can set the stage for tumor progression to occur. Thus, the two microenvironments act in sequence and play complementary roles in the development of overt neoplasia. This distinction has important implications for the understanding of disease pathogenesis and for the management of preneoplastic/neoplastic lesions at various stages of cancer development.

DNA damage response in human testes and testicular germ cell tumours: biology and implications for therapy

DNA damage response (DDR) is emerging as a physiological anti-cancer barrier in early stages of cancer development, as shown for several types of solid cancers derived from somatic cells. Here we discuss our recently published and unpublished results on the exceptional paucity of such constitutive activation of the DDR machinery in human testicular germ cell tumours (TGCTs), including their common pre-invasive stage of carcinoma in situ (CIS). Our conclusions are supported by immunohistochemical analyses of multiple markers of activated DNA damage signalling, such as the phosphorylated ATM and Chk2 checkpoint kinases and phosphorylated histone H2AX. We propose that the unique lack of DDR activation in TGCTs reflects the biology of their cell of origin, the gonocyte. Furthermore, we propose that the lack of DDR activation avoids the pressure to select for mutations in DDR genes such as p53 or ATM, and the resulting intact DDR machinery may have implications for the exceptional curability of TGCTs by DNA damaging therapies.

Low-volume, high-throughput sandwich immunoassays for profiling plasma proteins in mice: Identification of early-stage systemic inflammation in a mouse model of intestinal cancer

Mouse models of human cancers may provide a valuable resource for the discovery of cancer biomarkers. We have developed a practical strategy for profiling specific proteins in mouse plasma using low-volume sandwich-immunoassays. We used this method to profile the levels of 14 different cytokines, acute-phase reactants, and other cancer markers in plasma from mouse models of intestinal tumors and their wild-type littermates, using as little as 1.5 μl of diluted plasma per assay. Many of the proteins were significantly and consistently up-regulated in the mutant mice. The mutant mice could be distinguished nearly perfectly from the wild-type mice based on the combined levels of as few as three markers. Many of the proteins were up-regulated even in the mutant mice with few or no tumors, suggesting the presence of a systemic host response at an early stage of cancer development. These results have implications for the study of host responses in mouse models of cancers and demonstrate the value of a new low-volume, high-throughput sandwich-immunoassay method for sensitively profiling protein levels in cancer.

The impact of diet on differentiated breast tissue: how polarized cells may lose sense of direction in initial stages of cancer development

the impact of diet on differentiated breast tissue: how polarized cells may lose sense of direction in initial stages of cancer development