Using the DNA Integrity Number to Analyze DNA Quality in Specimens Collected from Liquid-Based Cytology after Fine-Needle Aspiration of Breast Tumors and Lesions.

INTRODUCTION: Cancer genome analysis using next-generation sequencing requires adequate and high-quality DNA samples. Genomic analyses were conventionally performed using formalin-fixed paraffin-embedded sections rather than cytology samples such as cell block or smear specimens. Specimens collected from liquid-based cytology (LBC) have the potential to be sources of high-quality DNA suitable for genetic analysis even after long-term storage. METHODS: We collected breast tumor/lesion fractions from 92 residual LBC specimens using fine-needle aspiration (FNA) biopsy, including breast carcinoma (1 invasive carcinoma and 4 ductal carcinomas in situ), papillomatous lesion (5 intraductal papillomas), and fibroepithelial lesion (19 phyllodes tumors and 53 fibroadenomas) samples, and others (1 ductal adenoma, 1 hamartoma, 1 fibrocystic disease, and 7 unknown). DNA was extracted from all samples and subjected to DNA integrity number (DIN) score analysis. RESULTS: Average DIN score collected from 92 LBC specimens was significantly higher score. In addition, high-quality DNA with high DIN values (7.39 ± 0.80) was successfully extracted more than 12 months after storage of residual LBC specimens. CONCLUSION: Residual LBC specimens collected from FNA of the breast were verified to carry high-quality DNA and could serve as an alternate source for genetic analysis.

Insight into the significance of Foxp3 + tumor-infiltrating lymphocytes in squamous cell lung cancer.

PURPOSE: Although developing a better understanding of tumor-infiltrating Foxp3 + lymphocytes (Foxp3 + TILs) might provide essential knowledge to predict response to immunotherapy and prognosis, our current knowledge about Foxp3 + TILs is inadequate. This study investigated the prognostic significance of tumor-infiltrating Foxp3 + lymphocytes (Foxp3 + TILs) in squamous cell lung cancer (SQ-LC) objectively. METHODS: Among patients with SQ-LC surgically resected in our institution between 2011 and 2017, those with pathological stage IA3-IIIA were immunohistochemically studied to evaluate Foxp3 + TILs in their tumor stroma. The impact of Foxp3 + TILs on relapse-free survival (RFS) was analyzed with Kaplan-Meier survival analysis and multivariate analysis using a Cox proportional hazards model/Fine-Gray model. RESULTS: This study analyzed 100 patients. Multivariate analysis showed that a large number of Foxp3 + TILs in the stroma does not associate with a poor prognosis, rather that a large number of Foxp3 + TILs (≥ 64 cells) tend to be associated with a more favorable prognosis than a small number of Foxp3 + TILs (< 64 cells) (large vs small number: HR, 0.56; 95% CI, 0.17-1.83; P = 0.34). Exploratory analysis also showed that in the two populations divided by a difference in Foxp3 expression levels, similar trends to the main analysis were observed. CONCLUSION: Our results showed that a large number of Foxp3 + TILs in the stroma may not associate with a poor prognosis in SQ-LC. To use the seemingly complicated information of Foxp3 + TILs as biomarkers, better understanding the diversity and heterogeneity of Foxp3 + TILs and analyzing their subpopulations that increase in the TME may be needed.

Insight into the significance of CD8+ tumor-infiltrating lymphocytes in squamous cell lung cancer.

BACKGROUND: Although there are great expectations regarding the use of tumor-infiltrating lymphocytes (TILs) to predict effects of immunotherapies and prognosis, knowledge about TILs remains insufficient for clinical application. METHODS: We objectively investigated the prognostic significance of tumor-infiltrating CD8 + lymphocytes (CD8 + TILs) in squamous cell lung cancer (SQ-LC). Among patients who underwent surgical resection of SQ-LC in 2011-2017, 100 patients with pathological stage IA3-III were immunohistochemically studied to evaluate CD8 + TILs in the tumor stroma and parenchyma. The impact of CD8 + TILs on relapse-free survival was analyzed using a Kaplan-Meier survival analysis and multivariate analyses using Fine-Gray and Cox proportional hazards models. RESULTS: The multivariate analysis showed that large and small numbers, but not intermediate numbers, of CD8 + TILs in the tumor stroma may be related to a more favorable prognosis (small vs. intermediate: HR, 0.64; 95% CI: 0.29-1.41, p = 0.27; large vs. intermediate: HR, 0.48; 95% CI: 0.21-1.09, p = 0.08). In contrast, a large number of CD8 + TILs in the tumor parenchyma was associated with a poor prognosis (HR, 2.60; 95% CI: 0.91-7.42, p = 0.075). An exploratory analysis showed a potentially strong association between an extremely large number of CD8 + TILs in the tumor parenchyma and a poor prognosis, even with a large number of CD8 + TILs in the tumor stroma. CONCLUSION: Our study provided partial but important information on the significance of CD8 + TILs in SQ-LC. To use CD8 + TILs as biomarkers, a better understanding of CD8 + TILs as well as other important components in the tumor microenvironment and the inflammatory phenotypes they form may be needed.

REV7 is involved in outcomes of platinum-based chemotherapy in pancreatic cancer by controlling the DNA damage response.

REV7 is a multifunctional protein implicated in various biological processes, including DNA damage response. REV7 expression in human cancer cells affects their sensitivity to DNA-damaging agents. In the present study, we investigated the significance of REV7 in pancreatic ductal adenocarcinoma (PDAC). REV7 expression was immunohistochemically examined in 92 resected PDAC specimens and 60 endoscopic ultrasound-guided fine-needle aspiration biopsy (EUS-FNAB) specimens of unresectable PDAC treated with platinum-based chemotherapy, and its association with clinicopathologic features was analyzed. Although REV7 expression was not significantly associated with the progression of primary tumors (T-factor and Stage) in either resected or unresectable PDAC, decreased levels of REV7 expression in EUS-FNAB specimens of unresectable PDAC were significantly associated with better outcomes of platinum-based chemotherapy and a favorable prognosis. REV7-deficient PDAC cell lines showed suppressed cell growth and enhanced sensitivity to cisplatin in vitro. Tumor-bearing mice generated using REV7-deficient PDAC cell lines also showed enhanced sensitivity to cisplatin in vivo. RNA sequencing analysis using WT and REV7-deficient PDAC cell lines revealed that REV7 inactivation promoted the downregulation of genes involved in the DNA repair and the upregulation of genes involved in apoptosis. Our results indicate that decreased expression of REV7 is associated with better outcomes of platinum-based chemotherapy in PDAC by suppressing the DNA damage response. It is also suggested that REV7 is a useful biomarker for predicting the outcome of platinum-based chemotherapy and the prognosis of unresectable PDAC and is a potential target for PDAC treatment.

Identification of the promoter region regulating the transcription of the REV7 gene.

REV7 is involved in various biological processes including DNA repair and mutagenesis, cell cycle regulation, gene transcription, and carcinogenesis. REV7 is highly expressed in adult testicular germ cells as well as several malignant tumors. REV7 expression levels are associated with prognosis in several human cancers, however, the mechanism of REV7 transcriptional regulation has not been elucidated. In this study, we characterized the promoter region of the REV7 gene. A luciferase reporter assay using the human germ cell tumor cell line NEC8 was utilized to examine the upstream genomic region of REV7 for transcriptional activity, and two transcriptional activation regions were identified. We determined a small genomic region important for transcriptional activation using site-directed mutagenesis; this region is shared by several putative binding motifs for transcription factors, including the cAMP-responsive element modulator (CREM), cAMP-response element binding protein (CREB), and B-lymphocyte-induced maturation protein-1 (BLIMP-1). Exogenous CREM and CREB expression had no effect on the transcriptional activity in NEC8 cells or the human embryonic kidney cell line HEK293T. In contrast, exogenous BLIMP-1 expression increased luciferase reporter activity in HEK293T cells but unexpectedly decreased activity in NEC8 cells. Chromatin immunoprecipitation analysis demonstrated that BLIMP-1 binds to the genomic region near the binding motif in the REV7 promoter. Additionally, BLIMP-1 overexpression promoted endogenous REV7 expression in HEK293T cells. These findings suggest that BLIMP-1 may be a putative transcriptional regulator of REV7 in mammalian cells.

REV7 in Cancer Biology and Management.

DNA repair and cell cycle regulation are potential biological fields to develop molecular targeting therapies for cancer. Human REV7 was originally discovered as a homologous molecule to yeast Rev7, which is involved in DNA damage response and mutagenesis, and as the second homolog of yeast Mad2, involved in the spindle assembly checkpoint. Although REV7 principally functions in the fields of DNA repair and cell cycle regulation, many binding partners of REV7 have been identified using comprehensive analyses in the past decade, and the significance of REV7 is expanding in various other biological fields, such as gene transcription, epigenetics, primordial germ cell survival, neurogenesis, intracellular signaling, and microbial infection. In addition, the clinical significance of REV7 has been demonstrated in studies using human cancer tissues, and investigations in cancer cell lines and animal models have revealed the greater impacts of REV7 in cancer biology, which makes it an attractive target molecule for cancer management. This review focuses on the functions of REV7 in human cancer and discusses the utility of REV7 for cancer management with a summary of the recent development of inhibitors targeting REV7.

N(6)-methyladenosine methylation-regulated polo-like kinase 1 cell cycle homeostasis as a potential target of radiotherapy in pancreatic adenocarcinoma.

In pancreatic cancer, methyltransferase-like 3 (METTL3), a N(6)-methyladenosine (m6A) methyltransferase, has a favorable effect on tumors and is a risk factor for patients' prognosis. However, the details of what genes are regulated by METTL3 remain unknown. Several RNAs are methylated, and what genes are favored in pancreatic cancer remains unclear. By epitranscriptomic analysis, we report that polo-like kinase 1 (PLK1) is an important hub gene defining patient prognosis in pancreatic cancer and that RNA methylation is involved in regulating its cell cycle-specific expression. We found that insulin like growth factor 2 mRNA binding protein 2 (IGF2BP2) binds to m6A of PLK1 3' untranslated region and is involved in upregulating PLK1 expression and that demethylation of this site activates the ataxia telangiectasia and Rad3-related protein pathway by replicating stress and increasing mitotic catastrophe, resulting in increased radiosensitivity. This suggests that PLK1 methylation is essential for cell cycle maintenance in pancreatic cancer and is a new therapeutic target.

Clinicopathological Significance of BRCAness in Resectable Pancreatic Ductal Adenocarcinoma and Its Association With Anticancer Drug Sensitivity in Pancreatic Cancer Cells.

OBJECTIVE: The concept of BRCAness has been proposed as a homologous recombination repair dysfunction triggered by a genetic defect in the BRCA pathway including the BRCA1/2 mutations. A certain number of pancreatic ductal adenocarcinoma (PDAC) patients have BRCAness. However, a large-scale analysis of BRCAness in PDAC has not been performed. In addition, no basic studies have examined the significance of BRCAness in PDAC cell lines. METHODS: Ninety-two patients who underwent surgery for PDAC were enrolled. Formalin-fixed and paraffin-embedded specimens of resected PDACs were used to analyze BRCAness by multiplex ligation-dependent probe amplification. We also analyzed BRCAness in pancreatic cancer cell lines and the sensitivity to cisplatin and olaparib using a colony formation assay. RESULTS: Of the 92 patients with PDAC, 6 were detected to have BRCAness-positive PDAC (6.5%). No significant differences in overall survival and progression-free survival were observed between the BRCAness-positive and BRCAness-negative groups. One PDAC cell line, KP-2, was positive for BRCAness and was more sensitive to cisplatin and olaparib than the BRCAness-negative cell lines. CONCLUSIONS: Our results revealed that a considerable number of PDACs are positive for BRCAness, suggesting that BRCAness status could be a useful biomarker for selecting anticancer treatments for advanced or relapsed PDAC.

The Significance of CD109 Expression in Oropharyngeal Squamous Cell Carcinoma.

BACKGROUND/AIM: Up-regulation of CD109 occurs in malignant tumours, although its role is unknown. Here we aimed to evaluate the significance of CD109 expression in oropharyngeal squamous cell carcinoma (OPSCC). PATIENTS AND METHODS: Immunohistochemical analysis was performed to assess CD109 expression in 169 patients with OPSCC. We assessed the effects of small interfering RNA (siRNA)-mediated inhibition of CD109 expression on the proliferation and invasiveness of the human papillomavirus 16-positive (HPV16+) head and neck SCC cell line UM-SCC-47. RESULTS: Expression of CD109 was associated with higher tumour differentiation in p16+ OPSCC (p=0.0036), and the CD109+ subgroup experienced significantly shorter progression-free survival (p=0.03). UM-SCC-47 cells with siRNA-mediated inhibition of CD109 expression showed reduced invasiveness (p=0.07). CONCLUSION: CD109 expression is associated with poor prognosis of HPV16+ OPSCCs.

A case of solid-type pancreatic hamartoma presenting high apparent diffusion coefficient value: histopathological correlation and literature review.

Pancreatic hamartoma is a rare tumor-like malformation and could mimic other pancreatic tumors including malignant neoplasm. Due to its rarity, magnetic resonance (MR) imaging findings including those diffusion-weighted (DW) imaging have not been clarified. We present a curious case of pancreatic hamartoma presenting high apparent diffusion coefficient (ADC) value with histopathological correlation. A 49-year-old woman with a pancreatic mass found incidentally on ultrasonography for medical checkup was referred to our institution for further examination and treatment because it slightly enlarged in the follow-up examination. Contrast-enhanced computed tomography (CT) and gadoxetic acid disodium-enhanced MR imaging revealed a well-demarcated solid mass of 13 mm in diameter in the pancreas body, which was gradually and homogeneously enhanced in the delayed/transient phase. It showed hyper intensity on T2-weight and DW images, and the mean ADC value was high (1.86 × 10-3mm2/s). Laparoscopic distal pancreatectomy was conducted with suspicious preoperative diagnosis of pancreatic hypovascular neuroendocrine neoplasm (NEN). Histologically, the mass consisted of many disarranged small ducts without atypia embedded in abundant fibrous stroma and contained scant fatty tissue in the periphery, which was not identified on CT and MR images. There were no islets and peripheral nerves throughout the mass. Finally, it was pathologically diagnosed as a solid-type pancreatic hamartoma. Based on radiological-pathological correlation, it was considered that the abundant fibrous stroma and both the widely distributed myxomatous periductal stroma and scattered edematous stroma corresponded with delayed homogenous enhancement on CT/MR images and high ADC value, respectively. Although it is difficult to distinguish solid-type pancreatic hamartoma from other solid pancreatic neoplasms including hypovascular NEN on the basis of usual radiological findings, the high ADC value reflecting the specific pathology may be helpful for the differential diagnosis.

Upregulation of REV7 correlates with progression of malignant melanoma.

REV7 is a multifunctional protein implicated in DNA damage tolerance, cell cycle control, and gene expression, and is involved in the carcinogenesis of various human tumors. It has been reported that REV7 expression is associated with ultraviolet-induced mutagenesis; however, the role of REV7 expression in skin cancers, including malignant melanomas, remains unclear. In the present study, we investigated the clinical and biological significance of REV7 in malignant melanoma. Levels of REV7 expression in human skin cancers were evaluated immunohistochemically. Positive expression of REV7 was frequently observed in malignant melanomas, as well as in squamous cell carcinomas and basal cell carcinomas. Enhanced immunoreactivity to REV7 was closely linked with cell proliferation assessed by Ki-67 labeling indexes in the three skin cancers, and was related with tumor thickness in malignant melanomas. REV7 depletion in malignant melanoma cells MEWO and G361 suppressed cell proliferation, migration, and invasion abilities. REV7 depletion also affected the expression of intracellular signaling molecules AKT and ERK in MEWO cells, resulting in downregulation of ERK signal activation. In addition, REV7 depletion facilitated sensitivity to cisplatin, but not to dacarbazine, in MEWO cells. Our results suggest that REV7 expression correlates with disease progression of malignant melanoma.

CD109 expression in tumor cells and stroma correlates with progression and prognosis in pancreatic cancer.

CD109 is a glycosylphosphatidylinositol-anchored glycoprotein, whose expression is upregulated in some types of malignant tumors. High levels of CD109 in tumor cells have been reported to correlate with poor prognosis; however, significance of CD109 stromal expression in human malignancy has not been elucidated. In this study, we investigated the tumorigenic properties of CD109 in pancreatic ductal adenocarcinoma (PDAC). Immunohistochemical analysis of 92 PDAC surgical specimens revealed that positive CD109 expression in tumor cells was significantly associated with poor prognosis (disease-free survival, p = 0.003; overall survival, p = 0.002), and was an independent prognostic factor (disease-free survival, p = 0.0173; overall survival, p = 0.0104) in PDAC. Furthermore, CD109 expression was detected in the stroma surrounding tumor cells, similar to that of α-smooth muscle actin, a histological marker of cancer-associated fibroblasts. The stromal CD109 expression significantly correlated with tumor progression in PDAC (TNM stage, p = 0.033; N factor, p = 0.024; lymphatic invasion, p = 0.028). In addition, combined assessment of CD109 in tumor cells and stroma could identify the better prognosis group of patients from the entire patient population. In MIA PaCa-2 PDAC cell line, we demonstrated the involvement of CD109 in tumor cell motility, but not in PANC-1. Taken together, CD109 not only in the tumor cells but also in the stroma is involved in the progression and prognosis of PDAC, and may serve as a useful prognostic marker in PDAC.

Cytopathic effects and local immune responses in repeated neoadjuvant HSV-tk + ganciclovir gene therapy for prostate cancer.

OBJECTIVE: Cytopathic effects and local immune response were analyzed histologically in prostatic cancer (PCa) with in situ herpes simplex virus-thymidine kinase (HSV-tk)/ganciclovir (GCV) gene therapy (GT). METHODS: Four high-risk PCa patients who received HSV-tk/GCV GT were investigated. After two cycles of intraprostatic injection of HSV-tk and administration of GCV, radical prostatectomy was performed. Formalin-fixed, paraffin-embedded sections were evaluated using immunohistochemistry. PCa with hormone therapy (HT, n=3) or without neoadjuvant therapy (NT, n=4) that were equivalent in terms of risk were also examined as reference. Immunoreactively-positive cells were counted in at least three areas in cancer tissue. Labeling indices (LI) were calculated as percentage values. RESULTS: ssDNA LI in GT increased, indicating apoptosis, as well as tumor-infiltrating lymphocytes and CD68-positive macrophages, compared with their biopsies. GT cases showed significantly higher numbers of single-stranded DNA (ssDNA) LI, CD4/CD8-positive T cells and CD68-positive macrophages including M1/M2 macrophages than HT or NT cases. However, there was no significant difference in CD20-positive B cells among the types of case. There were strong correlations between CD8+ T cells and CD68+ macrophages (ρ=0.656, p<0.0001) as well as CD4+ T cells and CD20+ B cells (ρ=0.644, p<0.0001) in PCa with GT. CONCLUSIONS: Enhanced cytopathic effect and local immune response might be indicated in PCa patients with HSV-tk/GCV gene therapy.

Prognostic significance of galectin-3 expression in patients with resected NSCLC treated with platinum-based adjuvant chemotherapy.

BACKGROUND: Galectin-3 (GAL3), a protein encoded by the LGALS3 gene, plays diverse roles in cancer initiation, progression, and drug resistance. Accordingly, high GAL3 expression in tumor cells is associated with poor prognosis in non-small cell lung cancer (NSCLC). However, the prognostic impact of GAL3 expression on patients with resected NSCLC receiving platinum-based adjuvant chemotherapy (AC) remains unclear. This study aimed to determine the prognostic significance of GAL3 expression in NSCLC patients receiving platinum-based AC. METHODS: The study included 111 patients with completely resected stages II and IIIA NSCLC who were receiving platinum-based AC. GAL3 expression in cancer cells was evaluated immunohistochemically according to H-score ("histo score), with a score of ≥170 considered as high expression. The correlation of GAL3 expression with clinicopathological characteristics and survival was subsequently evaluated. RESULTS: In survival analysis, GAL3 expression was significantly associated with recurrence-free survival (RFS) and overall survival (OS). In multivariate analysis, GAL3 expression was an independent predictive factor of RFS rather than OS. CONCLUSIONS: GAL3 expression is a reliable biomarker to predict the prognosis of completely resected NSCLC patients receiving platinum-based AC.

Prognostic values of L-type amino acid transporter 1 and CD98hc expression in breast cancer.

AIMS: L-type amino acid transporter 1 (LAT1) is a major Na+-independent neutral amino acid transporter, forming a complex with CD98hc. The aim of this study is to investigate the significance of LAT1 and CD98hc in invasive breast cancer. METHODS: LAT1 and CD98hc expression was immunohistochemically assessed in 280 invasive breast cancers and analysed for association with clinicopathological features. RESULTS: High levels of LAT1 and CD98hc were observed in triple-negative breast cancers (TNBCs) possessing negative immunoreactivity with oestrogen receptor, progesterone receptor and human epidermal growth factor receptor 2, compared with non-TNBCs (NTNBCs), and were associated with lymph-node metastasis and higher nuclear grade. The high-LAT1-expression group showed a poor prognosis in NTNBC and TNBC, however, high-CD98hc-expression group showed a poor prognosis only in NTNBC. LAT1 and CD98hc expression could be the prognostic factors in univariate analyses, but not in multivariate analyses. Further, we found that invasive tumour components showed higher LAT1 and CD98hc expression than non-invasive tumour components. CONCLUSIONS: LAT1 and CD98hc may possess prognostic values in invasive breast cancer. LAT1 may be linked with cancer cell activities and disease progression in breast cancer.

Increased expression of REV7 in small cell lung carcinomas and its association with tumor cell survival and proliferation.

REV7 is involved in multiple biological processes including DNA damage tolerance, cell cycle regulation and gene expression, and is an accessory subunit of the mutation-prone DNA polymerase ζ. It has been reported that REV7 expression is associated with poor prognosis in several human cancers. The aim of this study is to investigate the significance of REV7 in lung carcinogenesis. Immunohistochemical analyses of surgically resected lung cancer specimens revealed that REV7 shows an increased expression in small cell lung carcinomas (SCLCs) when compared with other histological types of lung carcinoma. Association between REV7 expression levels and clinicopathological factors was investigated using SCLC cases with or without surgical resection. Our analyses revealed that high REV7 expression significantly correlated with tumor cell proliferation, assessed by Ki-67 labeling indices, and was negatively associated with distant metastasis and extensive-stage disease. No significant association was detected between REV7 expression and other factors, including prognosis or response to chemoradiotherapy in SCLC. Increase in REV7 expression in SCLC was confirmed using SCLC cell lines. In addition, siRNA-mediated depletion of REV7 activated the apoptotic pathway and suppressed cell growth in SCLC cells. These results suggest that REV7 plays an important role in tumor cell survival and proliferation in SCLC.

CD109 regulates in vivo tumor invasion in lung adenocarcinoma through TGF-ß signaling.

Stromal invasion is considered an important prognostic factor in patients with lung adenocarcinoma. The mechanisms underlying the formation of tumor stroma and stromal invasion have been studied in the lung; however, they are still unclear. CD109 is a glycosylphosphatidylinositol-anchored glycoprotein highly expressed in several types of human malignant tumors including lung cancers. In this study, we investigated the in vivo functions of CD109 protein in malignant lung tumors. Initially, we identified an association between higher expression of CD109 protein in human lung adenocarcinoma and a significantly worse prognosis, according to immunohistochemical analysis. We also showed that CD109 deficiency significantly reduced the area of stromal invasive lesions in a genetically engineered CD109-deficient lung adenocarcinoma mouse model, which correlated with the results observed in human lung adenocarcinoma. Furthermore, we identified latent TGF-ß binding protein-1 (LTBP1) as a CD109-interacting protein using mass spectrometry and confirmed their interaction by co-immunoprecipitation. Importantly, increased CD109 expression enhanced stromal TGF-ß activation in the presence of LTBP1. Therefore, these data suggest the significance of the regulation of TGF-ß signaling through CD109 and LTBP1 interaction in tumor stroma and also reveal the importance of CD109 expression levels in promoting lung cancer cell proliferation, migration, and invasion, and thus predicting the outcome of patients suffering from lung adenocarcinoma. Therefore, CD109 protein could be a potential therapeutic target for this disease.

SSEA-3 and 4 are not essential for the induction or properties of mouse iPS cells.

Stage-specific embryonic antigens (SSEA-1, 3, and 4) are carbohydrate antigens that have been used as markers of embryonic stem (ES) cells. However, the roles of these antigens in the establishment and maintenance of stemness of ES and induced pluripotent stem (iPS) cells are still poorly understood. This study investigated the biological and functional significance of globo-series glycolipids such as SSEA-3 and 4 in mouse iPS cells induced from tail-tip fibroblasts (TTFs) of α1,4Gal-T-knockout mice (lacking SSEA-3 and 4). These iPS cells were induced by retroviral transduction of four factors (Oct3/4, Sox2, Klf4, and c-Myc) into TTFs, and colonies were picked up. Morphologically, the colonies resembled ES cells and were positive for alkaline phosphatase and ES cell markers. Furthermore, in vitro-differentiated induction experiments after embryoid body formation revealed that some colonies derived from α1, 4Gal-T knockout mice were able to differentiate into three germ layers. Three germ layers were also observed in teratomas from iPS cells derived from α1,4Gal-T-knockout mice. These results suggest that SSEA-3 and 4 are not essential, at least for the establishment and maintenance of stemness of mouse iPS cells.

Prognostic significance of NAP1L1 expression in patients with early lung adenocarcinoma.

NAP1L1 is a key regulator of embryonic neurogenesis but its role in lung cancer remains unexplored. In this study, we investigated the relationship between NAP1L1 expression and the clinicopathological parameters and prognosis of non-small cell lung cancer patients. To this end, the expression of NAP1L1 in tumor samples was evaluated by immunohistochemistry. NAP1L1 expression was significantly associated with reduced differentiation (P = 0.00014), higher pathological TNM stages (P < 0.00001), lymph node metastasis (P < 0.00001), intrapulmonary metastasis (P = 0.02955), lymphatic invasion (P = 0.00019), vascular invasion (P = 0.00008) and poorer prognosis (P = 0.0008) of patients with adenocarcinoma. Moreover, multivariate analyses using the Cox-proportional hazards model confirmed that NAP1L1 expression increased the risk of death after adjusting for other clinicopathological factors (HR = 2.46, 95% CI, 1.22-4.96). Furthermore, NAP1L1 expression was identified as an independent poor prognostic factor in patients with resectable stage I lung adenocarcinoma. NAP1L1-siRNA-treated lung adenocarcinoma-derived A549 cells showed significant suppression of proliferation, migration, and invasion abilities. These findings suggest that NAP1L1 may be a novel predictive and prognostic marker in lung adenocarcinoma, particularly in those with stage I of the disease.

Inactivation of REV7 enhances chemosensitivity and overcomes acquired chemoresistance in testicular germ cell tumors.

REV7 is a multitasking protein involved in replication past DNA lesions, cell cycle regulation, and gene expression. REV7 is highly expressed in the adult testis and plays an essential role in primordial germ cell maintenance in mice. In this study, we analyzed whether REV7 can be a molecular target for the treatment of testicular germ cell tumors (TGCTs), in which acquired chemoresistance is a major cause of treatment failure. Strong expression of REV7 was detected in human TGCT tissues by immunohistochemistry. REV7 depletion in the TGCT cell lines suppressed cell proliferation and increased sensitivity to cisplatin and doxorubicin. cDNA microarray analysis revealed that REV7 depletion downregulated genes in the DNA repair gene set and upregulated genes in the apoptosis gene set. REV7 depletion-provoked chemosensitivity was associated with DNA double-strand break accumulation and apoptosis activation. In addition, inactivation of REV7 in cisplatin-resistant TGCT cells recovered chemosensitivity at almost equal levels as parental cells in vitro and in vivo. Our results indicate that inactivation of REV7 enhances chemosensitivity and overcomes chemoresistance in TGCT cells, suggesting REV7 as a potential therapeutic target in chemoresistant TGCTs.