Polygenic TB control and the sequence of innate/adaptive immune responses to infection: MHC-II alleles determine the size of the S100A8/9-producing neutrophil population.

Among several quantitative trait loci involved in tuberculosis (TB) control in mice, one was mapped within the chromosome 17 segment occupied by the H2 complex and another within the chromosome 3 segment comprising the S100A8/9 genes, which encode neutrophil inflammatory factor S100A8/9. Previously, we developed a panel of H2-congenic mouse strains differing by small segments of the major histocompatibility complex Class II (MHC-II) region from TB-susceptible H2j mice transferred onto the genetic background of the TB-resistant C57BL/6 (H2b) strain. Susceptible B6.I-9.3 mice differ from B6 progenitors by the alleles of their only classical MHC-II H2-Aß gene. The goals of the present study were to: (i) comprehensively characterise the differences in TB-related phenotypes between mice of the two strains and (ii) decipher interactions between the H2-Aß and S100A8/9 genes. Here, we describe the dynamics of TB-related phenotypes differentiating B6.I-9.3 and B6 mice (colony forming units counts, histopathology, lung immune cell infiltration and cytokine profiles). We show that disproportionally diminished CD4+ T-cell population, an enlarged S100A8/9-positive neutrophil population and higher S100A8/9 serum levels in B6.I-9.3 mice collectively form the 'susceptible' phenotype before infection. An increase in IL-17 and a decrease in intrferon-gamma production by CD4+ T-cells in these mice provide a mechanistic explanation of this phenotype. Using F2 segregation analysis, we show that the number of S100A8/9-producing neutrophils in lungs and spleens and the proportion of Th17 CD4+ T-cells in lungs are significantly lower in the presence of the MHC-II dominant 'resistant' b allele compared to the recessive 'susceptible' j/j genotype. This provides direct genetic evidence that MHC-II-regulated CD4+ T-cell landscapes determine neutrophil abundance before infection, an important pathogenic factor in TB immunity.

Tumor Suppressor Properties of Small C-Terminal Domain Phosphatases in Clear Cell Renal Cell Carcinoma.

Clear cell renal cell carcinoma (ccRCC) accounts for 80-90% of kidney cancers worldwide. Small C-terminal domain phosphatases CTDSP1, CTDSP2, and CTDSPL (also known as SCP1, 2, 3) are involved in the regulation of several important pathways associated with carcinogenesis. In various cancer types, these phosphatases may demonstrate either antitumor or oncogenic activity. Tumor-suppressive activity of these phosphatases in kidney cancer has been shown previously, but in general case, the antitumor activity may be dependent on the choice of cell line. In the present work, transfection of the Caki-1 cell line (ccRCC morphologic phenotype) with expression constructs containing the coding regions of these genes resulted in inhibition of cell growth in vitro in the case of CTDSP1 (p < 0.001) and CTDSPL (p < 0.05) but not CTDSP2. The analysis of The Cancer Genome Atlas (TCGA) data showed differential expression of some of CTDSP genes and of their target, RB1. These results were confirmed by quantitative RT-PCR using an independent sample of primary ccRCC tumors (n = 52). We observed CTDSPL downregulation and found a positive correlation of expression for two gene pairs: CTDSP1 and CTDSP2 (rs = 0.76; p < 0.001) and CTDSPL and RB1 (rs = 0.38; p < 0.05). Survival analysis based on TCGA data demonstrated a strong association of lower expression of CTDSP1, CTDSP2, CTDSPL, and RB1 with poor survival of ccRCC patients (p < 0.001). In addition, according to TCGA, CTDSP1, CTDSP2, and RB1 were differently expressed in two subtypes of ccRCC-ccA and ccB, characterized by different survival rates. These results confirm that CTDSP1 and CTDSPL have tumor suppressor properties in ccRCC and reflect their association with the more aggressive ccRCC phenotype.

An In Vivo Model of Separate M. tuberculosis Phagocytosis by Neutrophils and Macrophages: Gene Expression Profiles in the Parasite and Disease Development in the Mouse Host.

The role of neutrophils in tuberculosis infection remains less well studied compared to that of the CD4+ T-lymphocytes and macrophages. Thus, alterations in Mycobacterium tuberculosis transcription profile following phagocytosis by neutrophils and how these shifts differ from those caused by macrophage phagocytosis remain unknown. We developed a mouse model that allows obtaining large amounts of either neutrophils or macrophages infected in vivo with M. tuberculosis for mycobacteria isolation in quantities sufficient for the whole genome RNA sequencing and aerosol challenge of mice. Here, we present: (i) the differences in transcription profiles of mycobacteria isolated from liquid cultures, neutrophils and macrophages infected in vivo; (ii) phenotypes of infection and lung inflammation (life span, colony forming units (CFU) counts in organs, lung pathology, immune cells infiltration and cytokine production) in genetically TB-susceptible mice identically infected via respiratory tract with neutrophil-passaged (NP), macrophage-passaged (MP) and conventionally prepared (CP) mycobacteria. Two-hour residence within neutrophils caused transcriptome shifts consistent with mycobacterial transition to dormancy and diminished their capacity to attract immune cells to infected lung tissue. Mycobacterial multiplication in organs did not depend upon pre-phagocytosis, whilst survival time of infected mice was shorter in the group infected with NP bacilli. We also discuss possible reasons for these phenotypic divergences.

Prolonged infection triggered by dormant Mycobacterium tuberculosis: Immune and inflammatory responses in lungs of genetically susceptible and resistant mice.

We developed an approach for substantial attenuation of Mycobacterium tuberculosis by prolonged culturing under gradually acidifying conditions. Bacteria subjected to acidification lost the capacity to form colonies on solid media, but readily resuscitated their growth in the murine host, providing a useful model to study in vivo development of infection mimicking latent and reactivation tuberculosis (TB) in humans. Here we characterize biomarkers of lung pathology and immune responses triggered by such attenuated bacteria in genetically TB-susceptible and resistant mice. In susceptible I/St mice, CFU counts in lungs and spleens were ~1.5-log higher than in resistant B6 mice, accompanied by diffuse pneumonia and excessive lung infiltration with highly activated CD44+CD62L- T-lymphocytes resulting in death between months 7-9 post challenge. B6 mice were characterized by development of local inflammatory foci, higher production of pro-inflammatory IL-6 and IL-11 cytokines and a more balanced T-cell activation in their lungs. CFU counts remained stable in B6 mice during the whole 18-mo observation period, and all mice survived. Thus, we established a mouse model of fatal reactivation TB vs. indefinite mycobacterial possession after identical challenge and characterized the features of immune responses in the lung tissue underlining these polar phenotypes.

Tumor suppressor properties of the small C-terminal domain phosphatases in non-small cell lung cancer.

Non-Small Cell Lung Cancer (NSCLC) is responsible for the majority of deaths caused by cancer. Small C-terminal domain (CTD) phosphatases (SCP), CTDSP1, CTDSP2 and CTDSPL (CTDSPs) belong to SCP/CTDSP subfamily and are involved in many vital cellular processes and tumorigenesis. High similarity of their structures suggests similar functions. However their role in NSCLC remains insufficiently understood. For the first time we revealed the suppressor function of CTDSPs leading to a significant growth slowdown and senescence of A549 lung adenocarcinoma (ADC) cells in vitro. Their tumor-suppressive activity can be realized through increasing the proportion of the active form of Rb protein dephosphorylated at Ser807/811, Ser780, and Ser795 (P<0.05) thereby negatively regulating cancer cell proliferation. Moreover, we observed that a frequent (84%, 39/46) and highly concordant (Spearman's rank correlation coefficient (rs) = 0.53-0.62, P≤0.01) down-regulation of CTDSPs and RB1 is characteristic of primary NSCLC samples (n=46). A clear difference in their mRNA levels was found between lung ADCs with and without lymph node metastases, but not in squamous cell carcinomas (SCCs) (P≤0.05). Based on The Cancer Genome Atlas (TCGA) data and the results obtained using the CrossHub tool, we suggest that the well-known oncogenic cluster miR-96/182/183 could be a common expression regulator of CTDSPs. Indeed, according to our qPCR, the expression of CTDSPs negatively correlates with these miRs, but positively correlates with their intronic miR-26a/b. Our results reflect functional association of CTDSP1, CTDSP2, and CTDSPL, expand knowledge about their suppressor properties through Rb dephosphorylation and provide new insights into the regulation of NSCLC growth.

Reciprocal control of Mycobacterium avium and Mycobacterium tuberculosis infections by the alleles of the classic Class II H2-Aß gene in mice.

Genetic control of host susceptibility to M. avium, an important lung pathogen of immune-compromised individuals, remains incompletely defined. Apart from the slc11a1 (Nramp1) gene, which plays a pivotal role in genetic control of a few intracellular pathogens, including M. avium, in mice, we know nothing about genetic loci determining susceptibility to and/or severity of M. avium-triggered disease. Previously, our lab developed a panel of H2-congenic, recombinant mouse strains for identification of the MHC genes involved in the control of M. tuberculosis infection. In the present study, we applied a few recombinant strains from this panel to study $ possible influence of allelic variations in classical Class II genes on the development of M. avium infection. Our results demonstrate a clear difference in lung pathology, post-infection survival time, lung neutrophil influx and corresponding chemokine/cytokine responses, as well as the degree of lung T lymphocyte activation, between mouse strains differing by the alleles of a single highly polymorphic Class II H2-Aß gene. Paradoxically, mice carrying the H2-Aßb allele, which provides a notable protective effect against M. tuberculosis compared to the H2-Aßj allele, were more susceptible to M. avium infection as indicated by several parameters of the disease. We discuss possible reasons for such a reciprocal expression of phenotypes determined by a single allelic variant during two "similar" infections that may concern differences in virulence, NO-sensitivity, intracellular life style and antigenic composition between these two mycobacterial species.

A new model for chronic and reactivation tuberculosis: Infection with genetically attenuated Mycobacterium tuberculosis in mice with polar susceptibility.

TB infection in mice develops relatively rapidly which interferes with experimental dissection of immune responses and lung pathology features that differ between genetically susceptible and resistant hosts. Earlier we have shown that the M. tuberculosis strain lacking four of five Rpf genes (ΔACDE) is seriously attenuated for growth in vivo. Using this strain, we assessed key parameters of lung pathology, immune and inflammatory responses in chronic and reactivation TB infections in highly susceptible I/St and more resistant B6 mice. ΔACDE mycobacteria progressively multiplied only in I/St lungs, whilst in B6 lung CFU counts decreased with time. Condensed TB foci apeared in B6 lungs at week 4 of infection, whilst in I/St their formation was delayed. At the late phase of infection, in I/St lungs TB foci fused resulting in extensive pneumonia, whereas in B6 lungs pathology was limited to condensed foci. Macrophage and neutrophil populations characteristically differed between I/St and B6 mice at early and late stages of infection: more neutrophils accumulated in I/St and more macrophages in B6 lungs. The expression level of chemokine genes involved in neutrophil influx was higher in I/St compared to B6 lungs. B6 lung cells produced more IFN-γ, IL-6 and IL-11 at the early and late phases of infection. Overall, using a new mouse model of slow TB progression, we demonstrate two important features of ineffective infection control underlined by shifts in lung inflammation: delay in early granuloma formation and fusion of granulomas resulting in consolidated pneumonia late in the infectious course.

Local targeting NF-κB in the lung tissue of TB-infected mice diminishes the level of pathology.

Mice of the genetically TB-susceptible strain I/St were infected with ∼100 CFU of Mycobacterium tuberculosis strain H37Rv, and after week 3 post-infection treated by inhalations of the NBD peptide selectively blocking NF-κB activation pathway. This therapy resulted in a pronounced attenuation of lung pathology and down-regulation of the expression of several genes encoding major inflammatory molecules, but did not diminish the level of mycobacterial multiplication in the lungs.

B-lymphocytes forming follicle-like structures in the lung tissue of tuberculosis-infected mice: Dynamics, phenotypes and functional activity.

During tuberculosis (TB) infection, B cells form follicles in close vicinity of lung granuloma. We assessed the dynamics of follicle formation, surface phenotypes and functional activity of lung B cells during TB course in genetically susceptible mice. The follicles appeared early post infection and peaked at weeks 7-8. Lung B cells resembled classical B2 cells (CD19+IgMloIgDhiCD1d-CD21/35intCD5-CD11b-CD43-), but differed from them by the absence of B2 marker CD23. Lung B-cells constitutively expressed MHC II molecules, presented mycobacterial antigens to immune CD4+ T-cells and produced high amounts of IL-6 and IL-11, but no classical type 1 (TNF-α, IFN-γ), or anti-inflammatory (IL-10, TGF-ß) cytokines. The total antibody response in tuberculous lung showed almost no specificity to mycobacteria. A panel of monoclonal antibodies obtained from lung B cells contained only few clones with reactivity to mycobacteria. Our results suggest that anti-TB B cell response in the lung has clear pathological and doubtful protective role.

Peripheral T-Cell Lymphoma of the Submandibular Salivary Gland as an Unusual Manifestation of Richter's Syndrome: A Case Report and Literature Review.

Richter's syndrome is the development of high-grade non-Hodgkin lymphoma (NHL) or Hodgkin lymphoma in patients with chronic lymphocytic leukemia (CLL)/small lymphocytic lymphoma (SLL). In most patients with Richter's syndrome, the high-grade NHL is diffuse large B-cell lymphoma. Only a small minority of CLL/SLL patients develop T-cell malignancies. Herein, we describe a 40-year-old male patient presenting with peripheral T-cell lymphoma not otherwise specified (PTCL-NOS) in the submandibular salivary gland, two years after the diagnosis of CLL/SLL. The PTCL-NOS consisted of small lymphocytes, which complicated diagnosis. Immunohistochemical, cytological, and molecular studies allowed the correct diagnosis of composite lymphoma (SLL/PTCL-NOS) of the submandibular salivary gland. The PTCL-NOS had a cytotoxic phenotype and aberrant expression of CD79a. There was no evidence to suggest that the PTCL-NOS of the submandibular salivary gland developed from an intimately associated submandibular lymph node or by PTCL-NOS dissemination. A review of the literature and presented case suppose that the PTCLs developed following CLL/SLL have the cytotoxic phenotype and can clinically mimic typical Richter's syndrome.

In Vitro Activity of 3-Triazeneindoles against Mycobacterium tuberculosis and Mycobacterium avium.

Among 230 target-synthesized indole-based compounds, seven 3-triazenoindoles showed MICs of 0.2 to 0.5 µg/ml against Mycobacterium tuberculosis strain H37Rv and isoniazid-resistant human isolate CN-40. The TU112 compound was active also against a dormant form of M. tuberculosis Some of these triazenoindoles were active against Mycobacterium avium, with MICs of 0.05 to 0.5 µg/ml. The selectivity indices (SI) for M. tuberculosis and M. avium were significantly higher than 10, making these compounds acceptable for the next testing step.

Tumor Suppressor Function of the SEMA3B Gene in Human Lung and Renal Cancers.

The SEMA3B gene is located in the 3p21.3 LUCA region, which is frequently affected in different types of cancer. The objective of our study was to expand our knowledge of the SEMA3B gene as a tumor suppressor and the mechanisms of its inactivation. In this study, several experimental approaches were used: tumor growth analyses and apoptosis assays in vitro and in SCID mice, expression and methylation assays and other. With the use of the small cell lung cancer cell line U2020 we confirmed the function of SEMA3B as a tumor suppressor, and showed that the suppression can be realized through the induction of apoptosis and, possibly, associated with the inhibition of angiogenesis. In addition, for the first time, high methylation frequencies have been observed in both intronic (32-39%) and promoter (44-52%) CpG-islands in 38 non-small cell lung carcinomas, including 16 squamous cell carcinomas (SCC) and 22 adenocarcinomas (ADC), and in 83 clear cell renal cell carcinomas (ccRCC). Correlations between the methylation frequencies of the promoter and the intronic CpG-islands of SEMA3B with tumor stage and grade have been revealed for SCC, ADC and ccRCC. The association between the decrease of the SEMA3B mRNA level and hypermethylation of the promoter and the intronic CpG-islands has been estimated in renal primary tumors (P < 0.01). Using qPCR, we observed on the average 10- and 14-fold decrease of the SEMA3B mRNA level in SCC and ADC, respectively, and a 4-fold decrease in ccRCC. The frequency of this effect was high in both lung (92-95%) and renal (84%) tumor samples. Moreover, we showed a clear difference (P < 0.05) of the SEMA3B relative mRNA levels in ADC with and without lymph node metastases. We conclude that aberrant expression and methylation of SEMA3B could be suggested as markers of lung and renal cancer progression.

Neutrophils exacerbate tuberculosis infection in genetically susceptible mice.

Mice of the I/St inbred strain genetically hyper-susceptible to TB infection and prone to form neutrophil-abundant necrotic lung lesions and relatively resistant mice of the C57BL/6 (B6) strain were infected with 100 CFU of M. tuberculosis H37Rv. To verify the role of neutrophils in TB immunity, we selectively depleted neutrophils from infected mice with highly specific 1A8 anti-Ly6G antibodies at day 2 and 6 post-challenge. Depletion of neutrophils resulted in reduced lung tissue pathology, mycobacterial CFU counts and an increase of the survival time in genetically susceptible I/St, but not in B6 mice. Furthermore, we demonstrated that in vivo neutrophil depletion at the onset of TB infection results in a significant increase in numbers of mycobacteria-specific IFN-γ-producing T-cells at the time point when the acquired immunity to mycobacteria is fully developed. These results suggest antagonistic activity of neutrophils and immune T-cells in the course of TB infection and provide further evidence of deleterious rather than protective role of the former.

Reactivation of dormant "non-culturable" Mycobacterium tuberculosis developed in vitro after injection in mice: both the dormancy depth and host genetics influence the outcome.

Three stocks of Mycobacterium tuberculosis H37Rv were cultured in vitro under prolonged hypoxic or acidified conditions until partial or complete loss of the capacity to form colonies on agar medium was achieved. Such dormant "non-culturable" mycobacteria were assessed for the growth resuscitation after intra-tracheal injection into mice of the two inbred strains with different genetic susceptibility to M. tuberculosis-triggered disease: hyper-susceptible I/St and relatively resistant B6. The results indicate that bacteria which are able to resuscitate spontaneously in liquid medium in vitro started to multiply in organs of infected mice, and that the outcome of such infection strongly depended upon the level of genetic TB susceptibility. However, dormant bacteria required inducers for resuscitation in vitro lost the capacity to multiply even in genetically susceptible mice. The established model of dormancy/reactivation is suitable for the studying host-pathogen interactions and testing vaccine and drug candidates specifically targeting latent TB.

Latent tuberculosis infection: what we know about its genetic control?

About 90% of all cases of tuberculosis (TB) infection are comprised of latent mycobacterial persistence in the absence of clinical manifestations. In a proportion of latently infected individuals infection eventually reactivates and becomes contagious, seriously influencing epidemiological situation. Mechanisms of Mycobacterium tuberculosis transition to dormancy and TB reactivation are poorly understood, and biological markers of latency remain largely unknown. Data are accumulating that the dynamical equilibrium between the parasite and the host (expressed as a long term asymptomatic infection) and its abrogation (expressed as a reactivation disease) are genetically controlled by both parties. In this short review, the authors summarize the results of experimental studies on genetic regulation of the latent TB infection.

Epigenetic alterations of chromosome 3 revealed by NotI-microarrays in clear cell renal cell carcinoma.

This study aimed to clarify epigenetic and genetic alterations that occur during renal carcinogenesis. The original method includes chromosome 3 specific NotI-microarrays containing 180 NotI-clones associated with 188 genes for hybridization with 23 paired normal/tumor DNA samples of primary clear cell renal cell carcinomas (ccRCC). Twenty-two genes showed methylation and/or deletion in 17-57% of tumors. These genes include tumor suppressors or candidates (VHL, CTDSPL, LRRC3B, ALDH1L1, and EPHB1) and genes that were not previously considered as cancer-associated (e.g., LRRN1, GORASP1, FGD5, and PLCL2). Bisulfite sequencing analysis confirmed methylation as a frequent event in ccRCC. A set of six markers (NKIRAS1/RPL15, LRRN1, LRRC3B, CTDSPL, GORASP1/TTC21A, and VHL) was suggested for ccRCC detection in renal biopsies. The mRNA level decrease was shown for 6 NotI-associated genes in ccRCC using quantitative PCR: LRRN1, GORASP1, FOXP1, FGD5, PLCL2, and ALDH1L1. The majority of examined genes showed distinct expression profiles in ccRCC and papillary RCC. The strongest extent and frequency of downregulation were shown for ALDH1L1 gene both in ccRCC and papillary RCC. Moreover, the extent of ALDH1L1 mRNA level decrease was more pronounced in both histological types of RCC stage III compared with stages I and II (P = 0.03). The same was observed for FGD5 gene in ccRCC (P < 0.06). Dedicated to thememory of Eugene R. Zabarovsky.

Genetic and epigenetic analysis of non-small cell lung cancer with NotI-microarrays.

This study aimed to clarify genetic and epigenetic alterations that occur during lung carcinogenesis and to design perspective sets of newly identified biomarkers. The original method includes chromosome 3 specific NotI-microarrays containing 180 NotI clones associated with genes for hybridization with 40 paired normal/tumor DNA samples of primary lung tumors: 28 squamous cell carcinomas (SCC) and 12 adenocarcinomas (ADC). The NotI-microarray data were confirmed by qPCR and bisulfite sequencing analyses. Forty-four genes showed methylation and/or deletions in more than 15% of non-small cell lung cancer (NSCLC) samples. In general, SCC samples were more frequently methylated/deleted than ADC. Moreover, the SCC alterations were observed already at stage I of tumor development, whereas in ADC many genes showed tumor progression specific methylation/deletions. Among genes frequently methylated/deleted in NSCLC, only a few were already known tumor suppressor genes: RBSP3 (CTDSPL), VHL and THRB. The RPL32, LOC285205, FGD5 and other genes were previously not shown to be involved in lung carcinogenesis. Ten methylated genes, i.e., IQSEC1, RBSP3, ITGA 9, FOXP1, LRRN1, GNAI2, VHL, FGD5, ALDH1L1 and BCL6 were tested for expression by qPCR and were found downregulated in the majority of cases. Three genes (RBSP3, FBLN2 and ITGA9) demonstrated strong cell growth inhibition activity. A comprehensive statistical analysis suggested the set of 19 gene markers, ANKRD28, BHLHE40, CGGBP1, RBSP3, EPHB1, FGD5, FOXP1, GORASP1/TTC21, IQSEC1, ITGA9, LOC285375, LRRC3B, LRRN1, MITF, NKIRAS1/RPL15, TRH, UBE2E2, VHL, WNT7A, to allow early detection, tumor progression, metastases and to discriminate between SCC and ADC with sensitivity and specificity of 80-100%.

Interleukin-11 drives early lung inflammation during Mycobacterium tuberculosis infection in genetically susceptible mice.

IL-11 is multifunctional cytokine whose physiological role in the lungs during pulmonary tuberculosis (TB) is poorly understood. Here, using in vivo administration of specific antibodies against IL-11, we demonstrate for the first time that blocking IL-11 diminishes histopathology and neutrophilic infiltration of the lung tissue in TB-infected genetically susceptible mice. Antibody treatment decreased the pulmonary levels of IL-11 and other key inflammatory cytokines not belonging to the Th1 axis, and down-regulated IL-11 mRNA expression. This suggests the existence of a positive feedback loop at the transcriptional level, which is further supported by up-regulation of IL-11 mRNA expression in the presence of rIL-11 in in vitro cultures of lung cells. These findings imply a pathogenic role for IL-11 during the early phase of Mycobacterium tuberculosis-triggered disease in a genetically susceptible host.

Differential expression of CHL1 gene during development of major human cancers.

BACKGROUND: CHL1 gene (also known as CALL) on 3p26.3 encodes a one-pass trans-membrane cell adhesion molecule (CAM). Previously CAMs of this type, including L1, were shown to be involved in cancer growth and metastasis. METHODOLOGY/PRINCIPAL FINDINGS: We used Clontech Cancer Profiling Arrays (19 different types of cancers, 395 samples) to analyze expression of the CHL1 gene. The results were further validated by RT-qPCR for breast, renal and lung cancer. Cancer Profiling Arrays revealed differential expression of the gene: down-regulation/silencing in a majority of primary tumors and up-regulation associated with invasive/metastatic growth. Frequent down-regulation (>40% of cases) was detected in 11 types of cancer (breast, kidney, rectum, colon, thyroid, stomach, skin, small intestine, bladder, vulva and pancreatic cancer) and frequent up-regulation (>40% of cases)--in 5 types (lung, ovary, uterus, liver and trachea) of cancer. Using real-time quantitative PCR (RT-qPCR) we found that CHL1 expression was decreased in 61% of breast, 60% of lung, 87% of clear cell and 89% papillary renal cancer specimens (P<0.03 for all the cases). There was a higher frequency of CHL1 mRNA decrease in lung squamous cell carcinoma compared to adenocarcinoma (81% vs. 38%, P = 0.02) without association with tumor progression. CONCLUSIONS/SIGNIFICANCE: Our results suggested that CHL1 is involved in the development of different human cancers. Initially, during the primary tumor growth CHL1 could act as a putative tumor suppressor and is silenced to facilitate in situ tumor growth for 11 cancer types. We also suggested that re-expression of the gene on the edge of tumor mass might promote local invasive growth and enable further metastatic spread in ovary, colon and breast cancer. Our data also supported the role of CHL1 as a potentially novel specific biomarker in the early pathogenesis of two major histological types of renal cancer.