[Correlation of PBX2/ELF2 expression with prognosis of non-small cell lung cancer].

OBJECTIVE: To investigate the relationship between pre B cell leukemia transcription factor 2 (PBX2)/Ets domain transcription factor 2 (ELF2) expression with prognosis of non-small cell lung cancer (NSCLC). METHODS: Expressions of ELF2 and PBX2 were examined in 206 patients of NSCLC by immunohistochemistry. The correlation of PBX2/ELF2 expression with valosin-containing protein (VCP) expression and clinicopathologic factors of NSCLC patients was analyzed. Chi-square test, Fisher's exact test and Cox's regression were used for statistical analysis. RESULTS: The level of PBX2/ELF2 expression was associated with VCP expression (P=0.0126). Univariate analysis showed that 5-y disease free survival and overall survival (OS) of NSCLC were correlated with expression of PBX2, PBX2/ELF2 and VCP, tumor size, histological differentiation, visceral pleural invasion, N and T in pTNM grades, and clinical stages (P<0.05). The 5-y OS was also related to vascular invasion (P=0.0322). Multivariate analysis revealed that the expression level of PBX2/ELF2 and histological differentiation were independent predictors for NSCLC. CONCLUSION: The level of PBX2/ELF2 expression is related to VCP expression, indicating that PBX2/ELF2-VCP pathway may be associated with the prognosis of NSCLC patients.

Dysregulated microRNAs affect pathways and targets of biologic relevance in nasal-type natural killer/T-cell lymphoma.

We performed a comprehensive genome-wide miRNA expression profiling of extranodal nasal-type natural killer/T-cell lymphoma (NKTL) using formalin-fixed paraffin-embedded tissue (n = 30) and NK cell lines (n = 6) compared with normal NK cells, with the objective of understanding the pathogenetic role of miRNA deregulation in NKTL. Compared with normal NK cells, differentially expressed miRNAs in NKTL are predominantly down-regulated. Re-expression of down-regulated miRNAs, such as miR-101, miR-26a, miR26b, miR-28-5, and miR-363, reduced the growth of the NK cell line and modulated the expression of their predicted target genes, suggesting the potential functional role of the deregulated miRNAs in the oncogenesis of NKTL. Taken together, the predicted targets whose expression is inversely correlated with the expression of deregulated miRNA in NKTL are significantly enriched for genes involved in cell cycle-related, p53, and MAPK signaling pathways. We also performed immunohistochemical validation for selected target proteins and found overexpression of MUM1, BLIMP1, and STMN1 in NKTL, and notably, a corresponding increase in MYC expression. Because MYC is known to cause repression of miRNA expression, it is possible that MYC activation in NKTL may contribute to the suppression of the miRNAs regulating MUM1, BLIMP1, and STMN1.

SIRPα/CD172a regulates eosinophil homeostasis.

Eosinophils are abundant in the lamina propria of the small intestine, but they rarely show degranulation in situ under steady-state conditions. In this study, using two novel mAbs, we found that intestinal eosinophils constitutively expressed a high level of an inhibitory receptor signal regulatory protein α (SIRPα)/CD172a and a low, but significant, level of a tetraspanin CD63, whose upregulation is closely associated with degranulation. Cross-linking SIRPα/CD172a on the surface of wild-type eosinophils significantly inhibited the release of eosinophil peroxidase induced by the calcium ionophore A23187, whereas this cross-linking effect was not observed in eosinophils isolated from mice expressing a mutated SIRPα/CD172a that lacks most of its cytoplasmic domain (SIRPα Cyto(-/-)). The SIRPα Cyto(-/-) eosinophils showed reduced viability, increased CD63 expression, and increased eosinophil peroxidase release with or without A23187 stimulation in vitro. In addition, SIRPα Cyto(-/-) mice showed increased frequencies of Annexin V-binding eosinophils and free MBP(+)CD63(+) extracellular granules, as well as increased tissue remodeling in the small intestine under steady-state conditions. Mice deficient in CD47, which is a ligand for SIRPα/CD172a, recapitulated these phenomena. Moreover, during Th2-biased inflammation, increased eosinophil cell death and degranulation were obvious in a number of tissues, including the small intestine, in the SIRPα Cyto(-/-) mice compared with wild-type mice. Collectively, our results indicated that SIRPα/CD172a regulates eosinophil homeostasis, probably by interacting with CD47, with substantial effects on eosinophil survival. Thus, SIRPα/CD172a is a potential therapeutic target for eosinophil-associated diseases.

Reactive oxygen species and aldehyde dehydrogenase activity in Hodgkin lymphoma cells.

Tumor cells with tumorigenic potential might be limited to a small population of cells, called cancer-initiating cells (CICs). CICs efficiently form colonies in vitro, yield both CIC and non-CIC populations, maintain reactive oxygen species (ROS) at low levels, show high aldehyde dehydrogenase (ALDH) activity, and are mostly in a quiescent state of the cell cycle. CICs of Hodgkin lymphoma (HL) are small in size, with low levels of ROS. The relationship between ROS level and ALDH activity in CICs was examined in HL cell lines. ROS-low and ALDH-high populations formed colonies in semi-solid cultures more efficiently than ROS-high and ALDH-low populations. ALDH-high populations yielded both ALDH-low and -high populations, whereas ALDH-low populations rarely yielded an ALDH-high population. The number of cells in a quiescent state was significantly greater in ROS-low than in ROS-high cells, whereas that of ALDH-high and ALDH-low cells was comparable to each other. These findings show that ALDH-high and ROS-low cells share CIC-like potential, but they differ in their cell cycle status, suggesting that CICs are comprised of cells with heterogeneous characteristics.

Tumour-associated macrophages in diffuse large B-cell lymphoma: a study of the Osaka Lymphoma Study Group.

AIMS: To evaluate the role of tumour-associated macrophages (TAMs) of the M1 and M2 types in the behaviour of diffuse large B-cell lymphoma (DLBCL). METHODS AND RESULTS: Double immunohistochemical staining of HLA-DR/CD68 (M1) or CD163/CD68 (M2) was performed in 101 cases of DLBCL. CD68+ cells represent the total number of TAMs. The average number of double-positive cells was counted, and the cut-off value was set at the mean number of counts, i.e. 30.7 and 27.0 for M1 TAMs and M2 TAMs, respectively. That for total TAMs was set at the 90th percentile number of total counts, i.e. 132.3. Cases were categorized into three pairs: high (34 cases) and low (67 cases) M1 TAM groups, high (39 cases) and low (62 cases) M2 TAM groups, and high (10 cases) and low (91 cases) total TAM groups. The difference in overall survival rates was statistically significant between the high and low M2 TAM groups (P < 0.01) and between the high and low total TAM groups (P < 0.05). Multivariate analysis revealed that the presence of a bulky mass and a higher number of M2 TAMs were significant factors for poor prognosis (P < 0.05). CONCLUSIONS: Estimation of specific type of macrophages, of the M1 and M2 types, is superior to the estimation of TAMs as a whole (CD68+ cells) for prediction of the prognosis of DLBCL patients.

Diffuse large B cell lymphoma with an interfollicular pattern of proliferation shows a favourable prognosis: a study of the Osaka Lymphoma Study Group.

AIMS: Diffuse large B cell lymphoma (DLBCL) occasionally shows an interfollicular pattern of proliferation (DLBCL-IF) preserving lymphoid follicles. In this study, clinicopathological findings in 31 cases of DLBCL-IF were analysed. METHODS AND RESULTS: The study group comprised 20 males and 11 females, with ages ranging from 41 to 87 (median 69) years. The primary site was lymph node in 25 cases, and unknown in six due to advanced stage at diagnosis. Eight cases were clinical Stage I, 10 were Stage II, four Stage III, and nine Stage IV. A polymorphous pattern of proliferation containing large B cells and inflammatory cells was found in about 60% of cases. The overall survival rate of the DLBCL-IF patients was better than that of a DLBCL control group (log-rank test; P < 0.05). Multivariate analysis revealed that an interfollicular pattern of proliferation showed marginal significance for favourable prognosis (P = 0.069). Immunohistochemical double staining with antibodies for HLA-DR/CD68 (markers for M1-tumour-associated macrophage [M1-TAM]) or CD163/CD68 (M2-TAM) revealed that all DLBCL-IF patients with a low M2 count were alive at the end of observation. CONCLUSIONS: These findings suggest that DLBCL-IF is a clinicopathological entity distinct from ordinary DLBCL. The possible origin of tumour cells in DLBCL-IF from marginal zone B cells is discussed.

Activated oncogenic pathways and therapeutic targets in extranodal nasal-type NK/T cell lymphoma revealed by gene expression profiling.

We performed comprehensive genome-wide gene expression profiling (GEP) of extranodal nasal-type natural killer/T-cell lymphoma (NKTL) using formalin-fixed, paraffin-embedded tissue (n = 9) and NK cell lines (n = 5) in comparison with normal NK cells, with the objective of understanding the oncogenic pathways involved in the pathogenesis of NKTL and to identify potential therapeutic targets. Pathway and network analysis of genes differentially expressed between NKTL and normal NK cells revealed significant enrichment for cell cycle-related genes and pathways, such as PLK1, CDK1, and Aurora-A. Furthermore, our results demonstrated a pro-proliferative and anti-apoptotic phenotype in NKTL characterized by activation of Myc and nuclear factor kappa B (NF-κB), and deregulation of p53. In corroboration with GEP findings, a significant percentage of NKTLs (n = 33) overexpressed c-Myc (45.4%), p53 (87.9%), and NF-κB p50 (67.7%) on immunohistochemistry using a tissue microarray containing 33 NKTL samples. Notably, overexpression of survivin was observed in 97% of cases. Based on our findings, we propose a model of NKTL pathogenesis where deregulation of p53 together with activation of Myc and NF-κB, possibly driven by EBV LMP-1, results in the cumulative up-regulation of survivin. Down-regulation of survivin with Terameprocol (EM-1421, a survivin inhibitor) results in reduced cell viability and increased apoptosis in tumour cells, suggesting that targeting survivin may be a potential novel therapeutic strategy in NKTL.

Enormous cystic tumor of peritoneal psammocarcinoma exhibiting complete response to Cisplatin and cyclophosphamide after suboptimal cytoreduction: case report and review of the literature.

Psammocarcinoma is a serous peritoneal tumor arising from the ovary or the peritoneum and characterized by low-grade nuclear features, extensive psammoma bodies, and invasiveness. Only 62 cases have ever been documented, 30 primary peritoneal and 32 primary ovarian, most of which presented as small tumors. Adjuvant therapies, including chemotherapy and radiation, were performed in 12 of the primary peritoneal cases, without any clear evidence of benefit. We present a case of an unusually large primary peritoneal psammocarcinoma with unexpected outcome. The patient was a 38-year-old woman with a tumor of the peritoneum which adhered densely to the uterus and rectum and developed into the intra-abdominal cavity and retroperitoneal space. After adhesiolysis of the tumor and rectum, suboptimal surgical reduction left a 4 cm × 2 cm tumor segment. Postoperative chemotherapy, consisting of paclitaxel and carboplatin (TC) for 1 course, and cyclophosphamide and cisplatin (CP) for 5 courses, was conducted. The residual tumor responded completely to the chemotherapy and the patient is alive today, with no evidence of disease 15 months after the surgery. Our case implies that CP therapy is a potential regimen of postoperative remission-induction therapy for suboptimally resected primary peritoneal psammocarcinoma.

Expression of aldehyde dehydrogenase 1 (ALDH1) in endometrioid adenocarcinoma and its clinical implications.

Aldehyde dehydrogenase 1 (ALDH1) is expressed in stem/progenitor cells, including cancer-initiating cells (CIC) of various organs. In the present study, ALDH1 expression was immunohistochemically examined in uterine endometrioid adenocarcinoma. The ALDH1 was expressed in a small portion of tumor cells, and these ALDH1-expressing cells were less mature than ALDH1-non-expressing cells. The ALDH1-expressing (ALDH1-hi) cells were more tumorigenic, resistant to anti-cancer agents and more invasive than ALDH1-lo cells. Culture of the sorted ALDH1-hi cells yielded both ALDH1-hi and ALDH1-lo cells, whereas ALDH1-lo cells yielded ALDH-lo cells alone. Clinically, a high-level of ALDH1 expression in tumor cells was correlated with T category, lymphatic invasion, recurrence and prognosis of patients. Patients with high ALDH1 expression showed poorer prognoses than those with low expression (P = 0.015 for disease-free survival [DFS] and P = 0.010 for overall survival [OS]), and high ALDH1 expression was an independent factor for poor prognosis. Aldehyde dehydrogenase 1 is a candidate for CIC marker for uterine endometrioid adenocarcinoma.

Tumorigenic potential of mononucleated small cells of Hodgkin lymphoma cell lines.

Tumor cells with tumorigenic potential are limited to a small cell population known as cancer stem cells (CSCs). CSCs yield both CSCs and non-CSCs, whereas non-CSCs do not yield CSCs. CSCs have not been identified in any malignant lymphomas. Hodgkin lymphoma (HL) is a mostly B-cell neoplasm that can be diagnosed by the presence of multinucleated (Reed-Sternberg; RS) cells admixed with Hodgkin cells with distinct nucleoli and various inflammatory cells. Here, the tumorigenic potential of cells with a single nucleus (S) and cells with multiple nuclei (M), which may be equivalent to Hodgkin and RS cells, respectively, was examined in HL cell lines L1236 and L428. Cultures of single S cells yielded both S and M cells, whereas M cell cultures yielded only M cells. When either cultured in methylcellulose or inoculated into NOD/SCID mice, the colony number and tumor size were both larger in S than in M cells. Concentrations of intracellular reactive oxygen species (ROS) were at low levels in a portion of S cells that abundantly expressed FoxO3a, a transcription factor that regulates ROS-degrading enzymes. In clinical samples of HL, FoxO3a was expressed in mononuclear Hodgkin cells but not in multinucleated RS cells. These findings suggest that smaller cells or Hodgkin cells that show low-ROS concentrations and high FoxO3a expression levels might be candidates for HL CSCs.

Epstein-barr virus in diffuse large B-Cell lymphoma in immunocompetent patients in Japan is as low as in Western Countries.

According to previous reports, the frequency of Epstein-Barr virus (EBV) positivity in diffuse large B-cell lymphoma is higher in East Asia (approximately 9%) than in Western countries. The presence of the EBV genome was examined in diffuse large B-cell lymphoma patients registered with the Osaka Lymphoma Study Group (OLSG) in Osaka, Japan, situated in East Asia. The EBV-positive rate was examined with in situ hybridization (ISH) in 484 immunocompetent diffuse large B-cell lymphoma patients registered with OLSG. The male-to-female ratio was 1.29, with ages ranging from 16 to 95 (median, 68) years. ISH with EBV-encoded small RNAs (EBER) probes revealed positive signals in the nuclei of tumor cells: the frequency of positively stained cells among all tumor cells was almost none in 458 cases, 5-10% in 5, 10-20% in 5, 20-50% in 11, and >50% in 5. When the frequency was >20% or >50%, the EBV-positive rate in the present series (3.3% or 1.0%) was rather similar to that reported in Western cases. Careful evaluation of patient backgrounds, including age distribution, type of lymphomas, exclusion of immunocompromised patients, and establishment of definite criteria for EBV positivity (>20%, >50%, or almost all tumor cells) are essential in comparing geographical differences.

Pretreatment leukocytosis is an indicator of poor prognosis in patients with cervical cancer.

OBJECTIVES: The aim of this study was to investigate the prognostic value of pretreatment leukocytosis in patients with cervical cancer in relation to well-established conventional risk factors. METHODS: The baseline characteristics and outcome data from 536 patients treated for cervical cancer between 1996 April to 2007 March were collected and reviewed. Cox proportional hazards regression model was used to identify independent prognostic factors for overall survival. Subsequently, the prognostic significance of pretreatment WBC count was prospectively investigated in 156 patients newly diagnosed cervical cancer from 2007 April to 2010 March. RESULTS: In a retrospective analysis, patients with leukocytosis (WBC ≥ 10,000/µl) showed significantly higher treatment failure rate (P < 0.0001) and shorter OS (P < 0.0001) than the patients without leukocytosis. Tumors from patients with leukocytosis showed significantly stronger immunoreactivity for G-CSF than those obtained from patients without leukocytosis. Multivariate analyses revealed that clinical stage, tumor diameter, histology, and elevated WBC count (≥ 10,000/µl) were significant prognostic factors in terms of overall survival. In a prospective investigation, patients with leukocytosis showed significantly higher treatment failure rate (P < 0.0001), shorter PFS (P < 0.0001), and higher serum G-CSF concentrations (p = 0.001) than the patients without leukocytosis. Multivariate analyses revealed that clinical stage, tumor diameter, and elevated WBC count were significant prognostic factors in terms of PFS. CONCLUSION: Pretreatment leukocytosis is an independent prognostic factor in patients with cervical cancer. Our finding can be used to identify patients with poor prognosis and to design future tailored clinical trials.

Infiltration of tumour-associated macrophages in prostate biopsy specimens is predictive of disease progression after hormonal therapy for prostate cancer.

OBJECTIVE: • To evaluate tumour-associated macrophage (TAM) infiltration in prostate biopsy specimens as a possible prognostic factor for prostate cancer (PCa) after hormonal therapy. PATIENTS AND METHODS: • Immunostaining of TAMs in prostate biopsy specimens was performed using a monoclonal antibody CD68 for 71 patients having PCa treated with hormonal therapy. • Six microscopic (×400) fields around the cancer foci were selected for TAM counting. RESULTS: • The median value of serum prostate-specific antigen (PSA) was 50.1 ng/mL, and the median TAM count was 22. • Recurrence-free survival was significantly better in patients with fewer TAMs (<22) than in those with higher numbers of TAMs (≥22) (P < 0.001). • TAM count was higher in those with higher serum PSA (PSA), higher Gleason score, clinical T stage or those with PSA failure. Cox multivariate analysis showed that TAM count is one of the prognostic factors for PCa treated by hormonal therapy (P < 0.0001). CONCLUSION: • TAM infiltration in prostate needle biopsy specimens is a useful predictive factor for PSA failure or progression of PCa after hormonal therapy.

Presence of B-cell clones in T-cell lymphoma.

OBJECTIVES: The presence of B-cell clones in 76 cases with peripheral T-cell lymphoma (PTCL) and precursor T-lymphoblastic lymphoma (T-LBL) and its correlation with Epstein-Barr virus (EBV) was studied. METHODS: DNA was extracted from paraffin sections and/or fresh-frozen samples and then used for clonality analysis using a modified BIOMED-2 polymerase chain reaction (PCR)-based method. RESULTS: T- and B-cell clones were detected in 59 (77.6%) and 14 (18.4%) of 76 patients, respectively: 90% and 30% of cases with PTCL, not otherwise specified, 76.4% and 17.6% of cases with angioimmunoblastic T-cell lymphoma, 77% and 7.6% of cases with adult T-cell lymphoma, 50% and 0% of cases with anaplastic large T-cell lymphoma, 62.5% and 12.5% of cases with T-LBL, and 50% and 0% of cases with intestinal T-cell lymphoma, respectively. Histological and immunohistochemical analyses revealed the presence of large B cells in lesional tissues, which were occasionally monoclonal. The presence of B-cell clones was highly associated with EBV positivity, as revealed by in situ hybridization. In two cases that were evaluated by serial histological and molecular examination, EBV-positive cells persisted in one and disappeared in the other. CONCLUSIONS: These findings suggest a role for EBV in the evolution of B-cell clones in T-cell lymphomas.

Caspase-1, caspase-8, and calpain are dispensable for IL-33 release by macrophages.

In addition to IL-1 and IL-18, IL-33 was recently identified as a member of the IL-1 cytokine family. rIL-33 can promote production of Th2-type cytokines by Th2 cells and mast cells in vitro. Administration of rIL-33 to mice results in increases in IgE secretion and eosinophilic inflammation. However, the precise immune cell source of IL-33 remains unclear. Moreover, although recombinant pro-IL-33 is cleaved by recombinant caspase-1 in vitro, as are pro-IL-1beta and pro-IL-18, the involvement of caspase-1 in pro-IL-33 cleavage remains controversial. In this study, we show that mouse peritoneal macrophages, but not splenic dendritic cells, produced IL-33 upon stimulation with LPS. Likewise, mouse bone marrow cell-derived cultured mast cells also produced a small, but significant amount of IL-33 via FcepsilonRI cross-linking, but not in response to stimulation with LPS. To our surprise, IL-33 release was found even in caspase-1-deficient, caspase-8 inhibitor-treated, and calpain inhibitor-treated macrophages. These observations suggest that caspase-1-, caspase-8-, and calpain-independent IL-33 production by macrophages and/or mast cells may contribute to the pathogenesis of Th2-type allergic inflammation.

The prevalence of human papillomavirus in oral premalignant lesions and squamous cell carcinoma in comparison to cervical lesions used as a positive control.

BACKGROUND: Previous reports concerning the prevalence of human papillomavirus (HPV) in oral squamous cell carcinoma (OSCC) have observed varied results. The aim of this study was to evaluate the prevalence of HPV in oral premalignant lesions (OPL) and OSCC. For accurate HPV detection in oral lesions, comparative analysis was performed on cervical lesions as positive controls. METHODS: Fifty-seven cases with OPL and 50 with OSCC were selected. Twenty-nine control cases were selected from cervical lesions. The HPV infection rate was analysed by consensus polymerase chain reaction (PCR) using the My09/My11 and Gp5+/Gp6+ primers, and genotyping detection was employed using a PCR-based micro-array. Immunohistochemical staining for p16(INK4a) was performed. RESULTS: Twenty-eight (96.6%) cases of cervical lesions were positive for HPV by consensus PCR and 24 cases (82.8%) were positive by genotyping. The total HPV-positive rate in cervical lesions was 96.6%. HPV-DNA was detected in nine cases (15.8%) of OPL and six cases (12.0%) of OSCC by consensus PCR. Six cases (10.5%) of OPL and three cases (6.0%) of OSCC were positive by genotyping. The total HPV-positive rate in oral lesions was 22.4% (26.3% of OPL and 18.0% of OSCC). In cervical lesions, immunohistochemistry of p16(INK4a) identified 27 cases (93.1%) as positive. Fifteen cases (26.3%) of OPL and eight cases (16.0%) of OSCC were positive for p16(INK4a). CONCLUSIONS: The HPV infection and p16(INK4a)-positive rates in oral lesions are lower than previously reported. This suggests that HPV may not play a major role in oral lesions although its involvement cannot completely be ruled out.

Epidemiology and pathogenesis of nasal NK/T-cell lymphoma: a mini-review.

Nasal NK/T-cell lymphoma (NKTCL) frequently presents with necrotic, granulomatous lesions in the upper respiratory tract, and usually shows a highly aggressive clinical course. Thus, it was initially included in the clinical condition of lethal midline granuloma. Recently, the disease has been recognized as a neoplastic proliferation of NK/T cells. The disease is much more frequent in Asian and Latin American countries than in Western countries, and is universally associated with Epstein-Barr virus (EBV) infection. Analyses of gene mutations, especially p53 and c-kit, revealed the different frequencies by district. Abnormalities of other genes have also been reported. Case-control studies showed that the exposure to pesticides and chemical solvents could be causative of NKTCL. Further studies including HLA antigen typing of patients is necessary to further clarify the disease mechanism.

Decreased infiltration of macrophage scavenger receptor-positive cells in initial negative biopsy specimens is correlated with positive repeat biopsies of the prostate.

Macrophage scavenger receptor (MSR)-positive inflammatory cells and tumor-associated macrophages (TAMs) have been reported to regulate the growth of various cancers. In this study, the infiltration of MSR-positive cells and TAMs was analyzed to predict the outcome of repeat biopsy in men diagnosed as having no malignancy at the first prostate biopsy. Repeat biopsy of the prostate was carried out in 92 patients who were diagnosed as having no malignancy at the first biopsy. Of these, 30 patients (32.6%) were positive for prostate cancer at the repeat biopsy. Tumor-associated macrophages and MSR-positive cells were immunohistochemically stained with mAbs CD68 and CD204, respectively. Six ocular measuring fields were chosen randomly under a microscope at x400 power in the initial negative biopsy specimens, and the mean TAM and MSR counts for each case were determined. No difference in TAM count was found between the cases with or without prostate cancer. By contrast, the MSR count in patients with cancer was significantly lower than that in patients without cancer at the repeat biopsy (P < 0.001). Logistic regression analysis indicated that the MSR count at first biopsy is a significantly better predictive factor for positive repeat biopsy than PSA velocity, interval between first and repeat biopsies, or TAM count. Decreased infiltration of MSR-positive cells in negative first biopsy specimens was correlated with positive findings in the repeat biopsy. The MSR count might be a good indicator for avoiding unnecessary repeat biopsies.

Tumorigenic role of orphan nuclear receptor NR0B1 in lung adenocarcinoma.

Cancer stem cells are a limited population of tumor cells that are thought to reconstitute whole tumors. The Hoechst dye exclusion assay revealed that tumors are composed of both a main population and a side population of cells, which are rich in cancer stem cells. NR0B1 is an orphan nuclear receptor that is expressed to a greater extent in the side population, as compared with the main population, of a lung adenocarcinoma cell line. In this study, we investigated the role of NR0B1 in lung adenocarcinoma cells. Reduction of NR0B1 expression levels in lung adenocarcinoma cell lines resulted in vulnerability to anti-cancer drugs and decreased abilities for invasion, in vitro colony formation, and tumorigenicity in non-obese diabetic/severe compromised immunodeficient mice. When 193 cases of lung adenocarcinoma were immunohistochemically examined, higher levels of NR0B1 expression correlated with higher rates of lymph node metastasis and recurrence. Multivariate analysis revealed high NR0B1 expression levels, stage of the disease, and size of tumor to be independent unfavorable prognostic factors for overall and disease-free survival rates. In clinical samples, NR0B1 expression levels inversely correlated to the proportion of methylated CpG sequences around the transcription initiation site of the NR0B1 gene, suggesting the epigenetic control of NR0B1 transcription in lung adenocarcinoma. In conclusion, NR0B1 might play a role in the malignant potential of lung adenocarcinoma.

Tumorigenic role of podoplanin in esophageal squamous-cell carcinoma.

BACKGROUND: Podoplanin, a mucin-type transmembrane glycoprotein, is thought to be one of the cancer stem cell markers for squamous-cell carcinoma of the vulva. The objectives of the present study were to examine the role of podoplanin in esophageal squamous-cell carcinoma (ESCC). METHODS: Expression of podoplanin was examined immunohistochemically in 61 cases of ESCC that had not been treated with chemotherapy or radiotherapy before surgery. Because cancer stem-cell quantities have been reported to increase with chemotherapy and radiotherapy, cases in patients who did not receive such prior therapies were included in this study. Cases with >10% tumor cells showing signals for podoplanin were categorized as podoplanin high, and the others were classified as podoplanin low. The effects of podoplanin on the behavior of cancer cells were evaluated in ESCC cell lines in which podoplanin expression was knocked down. RESULTS: To examine whether podoplanin could be used as a cancer stem cell marker for ESCC, podoplanin-positive and podoplanin-negative fractions were sorted separately from the ESCC cell line and cultured. Podoplanin-positive ESCC cells yielded both podoplanin-positive and podoplanin-negative cells, whereas few cells were obtained from podoplanin-negative ESCC cells. When podoplanin expression was knocked down, ESCC cell lines became vulnerable to anticancer drugs and showed defective invasion and tumorigenic activities. Nineteen (31.1%) of 61 cases were categorized as podoplanin high. Podoplanin-high cases were correlated with T category, stage of disease, lymphatic and vascular invasion, recurrence, and prognosis of patients. Podoplanin-low cases showed better overall and disease-free survival. CONCLUSIONS: There is a role for podoplanin in tumorigenesis and malignant progression in ESCC.