Genome-wide association study of cervical cancer suggests a role for ARRDC3 gene in human papillomavirus infection.

The development of cervical cancer is initiated by human papillomavirus (HPV) infection and involves both viral and host genetic factors. Genome-wide association studies (GWAS) of cervical cancer have identified associations in the HLA locus and two loci outside HLA, but the principal genes that control infection and pathogenesis have not been identified. In the present study, we performed GWAS of cervical cancer in East Asian populations, involving 2609 cases and 4712 controls in the discovery stage and 1461 cases and 3295 controls in the follow-up stage. We identified novel-significant associations at 5q14 with the lead single nucleotide polymorphism (SNP) rs59661306 (P = 2.4 × 10-11) and at 7p11 with the lead SNP rs7457728 (P = 1.2 × 10-8). In 5q14, the chromatin region of the GWAS-significant SNPs was found to be in contact with the promoter of the ARRDC3 (arrestin domain-containing 3) gene. In our functional studies, ARRDC3 knockdown in HeLa cells caused significant reductions in both cell growth and susceptibility to HPV16 pseudovirion infection, suggesting that ARRDC3 is involved in the infectious entry of HPV into the cell. Our study advances the understanding of host genes that are responsible for cervical cancer susceptibility and guides future research on HPV infection and cancer development.

Panel of autoantibodies against multiple tumor-associated antigens for detecting gastric cancer.

Gastric cancer is the second leading cause of cancer death in the world, and effective diagnosis is extremely important for good outcome. We assessed the diagnostic potential of an autoantibody panel that may provide a novel tool for the early detection of gastric cancer. We analyzed data from patients with gastric cancer and normal controls in test and validation cohorts. Autoantibody levels were measured against a panel of six tumor-associated antigens (TAAs) by ELISA: p53, heat shock protein 70, HCC-22-5, peroxiredoxin VI, KM-HN-1, and p90 TAA. We assessed serum autoantibodies in 100 participants in the test cohort. The validation cohort comprised 248 participants. Autoantibodies to at least one of the six antigens showed a sensitivity/specificity of 49.0% (95% confidence interval [CI], 39.2-58.8%)/92.4% (95% CI, 87.2-97.6%), and 52.0% (95% CI, 42.2-61.8%)/90.5% (95% CI, 84.8-96.3%) in the test and validation cohorts, respectively. In the validation cohort, no significant differences were seen when patients were subdivided based on age, sex, depth of tumor invasion, lymph node metastasis, distant metastasis, peritoneal dissemination, or TNM stage. Patients who were positive for more than two antibodies in the panel tended to have a worse prognosis than those who were positive for one or no antibody. Measurement of autoantibody response to multiple TAAs in an optimized panel assay to discriminate patients with early stage gastric cancer from normal controls may aid in the early detection of gastric cancer.

Functional interplay between MYCN, NCYM, and OCT4 promotes aggressiveness of human neuroblastomas.

Neuroblastoma is a pediatric solid tumor that originates from embryonic neural crest cells. The MYCN gene locus is frequently amplified in unfavorable neuroblastomas, and the gene product promotes the progression of neuroblastomas. However, the molecular mechanisms by which MYCN amplification contributes to stem cell-like states of neuroblastoma remain elusive. In this study, we show that MYCN and its cis-antisense gene, NCYM, form a positive feedback loop with OCT4, a core regulatory gene maintaining a multipotent state of neural stem cells. We previously reported that NCYM is co-amplified with the MYCN gene in primary human neuroblastomas and that the gene product promotes aggressiveness of neuroblastoma by stabilization of MYCN. In 36 MYCN-amplified primary human neuroblastomas, OCT4 mRNA expression was associated with unfavorable prognosis and was correlated with that of NCYM. The OCT4 protein induced both NCYM and MYCN in human neuroblastoma cells, whereas NCYM stabilized MYCN to induce OCT4 and stem cell-related genes, including NANOG, SOX2, and LIN28. In sharp contrast to MYCN, enforced expression of c-MYC did not enhance OCT4 expression in human neuroblastoma cells. All-trans retinoic acid treatment reduced MYCN, NCYM, and OCT4 expression, accompanied by the decreased amount of OCT4 recruited onto the intron 1 region of MYCN. Knockdown of NCYM or OCT4 inhibited formation of spheres of neuroblastoma cells and promoted asymmetric cell division in MYCN-amplified human neuroblastoma cells. These results suggest that the functional interplay between MYCN, NCYM, and OCT4 contributes to aggressiveness of MYCN-amplified human neuroblastomas.

Sendai virus-mediated expression of reprogramming factors promotes plasticity of human neuroblastoma cells.

Neuroblastoma (NB) is the most common extracranial solid tumor that originates from multipotent neural crest cells. NB cell populations that express embryonic stem cell-associated genes have been identified and shown to retain a multipotent phenotype. However, whether somatic reprogramming of NB cells can produce similar stem-cell like populations is unknown. Here, we sought to reprogram NB cell lines using an integration-free Sendai virus vector system. Of four NB cell lines examined, only SH-IN cells formed induced pluripotent stem cell-like colonies (SH-IN 4F colonies) at approximately 6 weeks following transduction. These SH-IN 4F colonies were alkaline phosphatase-positive. Array comparative genomic hybridization analysis indicated identical genomic aberrations in the SH-IN 4F cells as in the parental cells. SH-IN 4F cells had the ability to differentiate into the three embryonic germ layers in vitro, but rather formed NBs in vivo. Furthermore, SH-IN 4F cells exhibited resistance to cisplatin treatment and differentiated into endothelial-like cells expressing CD31 in the presence of vascular endothelial growth factor. These results suggest that SH-IN 4F cells are partially reprogrammed NB cells, and could be a suitable model for investigating the plasticity of aggressive tumors.

NCYM promotes calpain-mediated Myc-nick production in human MYCN-amplified neuroblastoma cells.

NCYM is a cis-antisense gene of MYCN and is amplified in human neuroblastomas. High NCYM expression is associated with poor prognoses, and the NCYM protein stabilizes MYCN to promote proliferation of neuroblastoma cells. However, the molecular mechanisms of NCYM in the regulation of cell survival have remained poorly characterized. Here we show that NCYM promotes cleavage of MYCN to produce the anti-apoptotic protein, Myc-nick, both in vitro and in vivo. NCYM and Myc-nick were induced at G2/M phase, and NCYM knockdown induced apoptotic cell death accompanied by Myc-nick downregulation. These results reveal a novel function of NCYM as a regulator of Myc-nick production in human neuroblastomas.

Frequency of brain metastases in non-small-cell lung cancer, and their association with epidermal growth factor receptor mutations.

BACKGROUND: The brain is a frequent site of metastases from non-small-cell lung cancer (NSCLC). We analyzed the frequency of brain metastases (BMs) from NSCLC in the era of magnetic resonance images, and evaluated the correlation between epidermal growth factor receptor (EGFR) mutations and BMs among East Asian patients. METHODS: Frequency, number, and size of BMs, and survival of 1,127 NSCLC patients were retrospectively reviewed. Mutation status of EGFR was evaluated in all cases, and its association with BMs was statistically evaluated. RESULTS: EGFR mutations were found for 331 cases (29.4 %). BM was the cause of primary symptoms for 52 patients (4.6 %), and found before initiation of treatment for 102 other patients (9.1 %); In addition to these 154 patients, 107 patients (9.5 %) developed BMs, giving a total of 261 patients (23.2 %) who developed BMs from 1,127 with NSCLC. BM frequency was higher among EGFR-mutated cases (31.4 %) than EGFR-wild cases (19.7 %; odds ratio: 1.86; 95 % confidence interval (CI) 1.39-2.49; P < 0.001). BMs from EGFR-mutated NSCLC were small, but often became disseminated. EGFR mutations accounted for 39.9 % of BMs, but patient survival after BMs was significantly longer for EGFR-mutated cases than for EGFR-wild cases (hazard ratio: 2.23; 95 % CI 1.62-3.10; P < 0.001). CONCLUSIONS: Patients with EGFR-mutated NSCLC were more likely to develop BMs, but apparently also survived longer after BMs.

Trametinib for a child with refractory Rosai-Dorfman-Destombes disease harboring a novel somatic mutation in MAP2K1.

Rosai-Dorfman-Destombes disease (RDD) is a rare histiocytosis characterized by accumulation of S100 + , CD68 + , and CD1a- histiocytes, with emperipolesis. It occurs predominantly in black adolescents and young adults, but rarely in Japanese children. Recently, oncogenic mutations in mitogen-activated protein kinase (MAPK) pathway genes were reported in 30-50% of patients with RDD, and several studies have described treatment of adult patients with MAPK inhibitors. Here, we present the case of a Japanese boy with refractory RDD without signs of cardiofaciocutaneous (CFC) syndrome who harbored MAP2K1 p.Lys59del and responded to trametinib. The patient had lymph node, nasal cavity, kidney, upper respiratory tract, and intracranial involvement. RDD progressed after multi-agent chemotherapy, but responded to trametinib (0.025 mg/kg). Trametinib did not eliminate the mass lesions, but trametinib plus minimal prednisolone (0.1 mg/kg) resulted in a good outcome for more than 15 months, without significant adverse effects. MAP2K1 p.Lys59del has been described as a germline mutation in a patient with CFC syndrome, but not as a somatic mutation in patients with malignancies. Trametinib may be a promising drug for children with RDD that is refractory to multi-agent chemotherapy. Its long-term efficacy and safety alone and in combination with chemotherapy should be investigated.

Copy number alterations in urothelial carcinomas: their clinicopathological significance and correlation with DNA methylation alterations.

The aim of this study was to clarify the genetic backgrounds underlying the clinicopathological characteristics of urothelial carcinomas (UCs). Array comparative genomic hybridization analysis using a 244K oligonucleotide array was performed on 49 samples of UC tissue. Losses of 2q33.3-q37.3, 4p15.2-q13.1 and 5q13.3-q35.3 and gains of 7p11.2-q11.23 and 20q13.12-q13.2 were correlated with higher histological grade, and gain of 7p21.2-p21.12 was correlated with deeper invasion. Losses of 6q14.1-q27 and 17p13.3-q11.1 and gains of 19q13.12-q13.2 and 20q13.12-q13.33 were correlated with lymph vessel involvement. Loss of 16p12.2-p12.1 and gain of 3q26.32-q29 were correlated with vascular involvement. Losses of 5q14.1-q23.1, 6q14.1-q27, 8p22-p21.3, 11q13.5-q14.1 and 15q11.2-q22.2 and gains of 7p11.2-q11.22 and 19q13.12-q13.2 were correlated with the development of aggressive non-papillary UCs. Losses of 1p32.2-p31.3, 10q11.23-q21.1 and 15q21.3 were correlated with tumor recurrence. Unsupervised hierarchical clustering analysis based on copy number alterations clustered UCs into three subclasses: copy number alterations associated with genome-wide DNA hypomethylation, regional DNA hypermethylation on C-type CpG islands and genome-wide DNA hypo- and hypermethylation were accumulated in clusters A, B(1) and B(2), respectively. Tumor-related genes that may encode therapeutic targets and/or indicators useful for the diagnosis and prognostication of UCs should be explored in the above regions. Both genetic and epigenetic events appear to accumulate during urothelial carcinogenesis, reflecting the clinicopathological diversity of UCs.

The protocadherins, PCDHB1 and PCDH7, are regulated by MeCP2 in neuronal cells and brain tissues: implication for pathogenesis of Rett syndrome.

BACKGROUND: Rett syndrome is a neurodevelopmental and autistic disease caused by mutations of Methyl-CpG-binding protein 2 (MECP2) gene. MeCP2 protein is mainly expressed in neurons and binds to methylated gene promoters to suppress their expression, indicating that Rett syndrome is caused by the deregulation of target genes in neurons. However, it is likely that there are more unidentified neuronal MeCP2-targets associated with the neurological features of RTT. RESULTS: Using a genome-microarray approach, we found 22 genomic regions that contain sites potentially regulated by MeCP2 based on the features of MeCP2 binding, DNA methylation, and repressive histone modification in human cell lines. Within these regions, Chromatin immunoprecipitation (ChIP) analysis revealed that MeCP2 binds to the upstream regions of the protocadherin genes PCDHB1 and PCDH7 in human neuroblastoma SH-SY5Y cells. PCDHB1 and PCDH7 promoter activities were down-regulated by MeCP2, but not by MBD-deleted MeCP2. These gene expression were up-regulated following MeCP2 reduction with siRNA in SH-SY5Y cells and in the brains of Mecp2-null mice. Furthermore, PCDHB1 was up-regulated in postmortem brains from Rett syndrome patients. CONCLUSIONS: We identified MeCP2 target genes that encode neuronal adhesion molecules using ChIP-on-BAC array approach. Since these protocadherin genes are generally essential for brain development, aberrant regulation of these molecules may contribute to the pathogenesis of the neurological features observed in Rett syndrome.

Diagnosis and prognostication of ductal adenocarcinomas of the pancreas based on genome-wide DNA methylation profiling by bacterial artificial chromosome array-based methylated CpG island amplification.

To establish diagnostic criteria for ductal adenocarcinomas of the pancreas (PCs), bacterial artificial chromosome (BAC) array-based methylated CpG island amplification was performed using 139 tissue samples. Twelve BAC clones, for which DNA methylation status was able to discriminate cancerous tissue (T) from noncancerous pancreatic tissue in the learning cohort with a specificity of 100%, were identified. Using criteria that combined the 12 BAC clones, T-samples were diagnosed as cancers with 100% sensitivity and specificity in both the learning and validation cohorts. DNA methylation status on 11 of the BAC clones, which was able to discriminate patients showing early relapse from those with no relapse in the learning cohort with 100% specificity, was correlated with the recurrence-free and overall survival rates in the validation cohort and was an independent prognostic factor by multivariate analysis. Genome-wide DNA methylation profiling may provide optimal diagnostic markers and prognostic indicators for patients with PCs.

Genome-wide DNA methylation profiles in renal tumors of various histological subtypes and non-tumorous renal tissues.

OBJECTIVE: The aim of this study is to clarify genome-wide DNA methylation profiles in renal tumors of various histological subtypes. METHODS: Bacterial artificial chromosome (BAC) array-based methylated CpG island amplification was performed using tissue samples of 17 patients with papillary renal cell carcinomas (RCCs), chromophobe RCCs and oncocytomas, and the results were compared with those from 51 patients with clear cell RCCs. RESULTS: Unsupervised hierarchical clustering analysis based on DNA methylation status clustered type 1 and type 2 papillary RCCs into different subclasses. Although chromophobe RCCs and oncocytomas were clustered into the same subclass, the DNA methylation status of 21 BAC clones was able to discriminate chromophobe RCCs from oncocytomas. The number of BAC clones showing DNA methylation alteration in non-tumorous renal tissue from patients with chromophobe RCCs and oncocytomas was smaller than that from patients with clear cell RCCs. Biphasic accumulation of DNA methylation alterations was observed in non-tumorous renal tissue from all 68 patients, and patients showing such alterations on more BAC clones had a poorer outcome than patients showing them on fewer BAC clones. CONCLUSIONS: DNA methylation profiles determining the histological subtypes of renal tumors developing in individual patients and/or patient outcome may be already established in non-tumorous renal tissue at the precancerous stage.

Genome-wide DNA methylation profiles in urothelial carcinomas and urothelia at the precancerous stage.

To clarify genome-wide DNA methylation profiles during multistage urothelial carcinogenesis, bacterial artificial chromosome (BAC) array-based methylated CpG island amplification (BAMCA) was performed in 18 normal urothelia obtained from patients without urothelial carcinomas (UCs) (C), 17 noncancerous urothelia obtained from patients with UCs (N), and 40 UCs. DNA hypo- and hypermethylation on multiple BAC clones was observed even in N compared to C. Principal component analysis revealed progressive DNA methylation alterations from C to N, and to UCs. DNA methylation profiles in N obtained from patients with invasive UCs were inherited by the invasive UCs themselves, that is DNA methylation alterations in N were correlated with the development of more malignant UCs. The combination of DNA methylation status on 83 BAC clones selected by Wilcoxon test was able to completely discriminate N from C, and diagnose N as having a high risk of carcinogenesis, with 100% sensitivity and specificity. The combination of DNA methylation status on 20 BAC clones selected by Wilcoxon test was able to completely discriminate patients who suffered from recurrence after surgery from patients who did not. The combination of DNA methylation status for 11 BAC clones selected by Wilcoxon test was able to completely discriminate patients with UCs of the renal pelvis or ureter who suffered from intravesical metachronous UC development from patients who did not. Genome-wide alterations of DNA methylation may participate in urothelial carcinogenesis from the precancerous stage to UC, and DNA methylation profiling may provide optimal indicators for carcinogenetic risk estimation and prognostication.

Erratum: Combining peptide TNIIIA2 with all-trans retinoic acid accelerates N-Myc protein degradation and neuronal differentiation in MYCN-amplified neuroblastoma cells.

[This corrects the article on p. 434 in vol. 9, PMID: 30906641.].

Targeting FROUNT with disulfiram suppresses macrophage accumulation and its tumor-promoting properties.

Tumor-associated macrophages affect tumor progression and resistance to immune checkpoint therapy. Here, we identify the chemokine signal regulator FROUNT as a target to control tumor-associated macrophages. The low level FROUNT expression in patients with cancer correlates with better clinical outcomes. Frount-deficiency markedly reduces tumor progression and decreases macrophage tumor-promoting activity. FROUNT is highly expressed in macrophages, and its myeloid-specific deletion impairs tumor growth. Further, the anti-alcoholism drug disulfiram (DSF) acts as a potent inhibitor of FROUNT. DSF interferes with FROUNT-chemokine receptor interactions via direct binding to a specific site of the chemokine receptor-binding domain of FROUNT, leading to inhibition of macrophage responses. DSF monotherapy reduces tumor progression and decreases macrophage tumor-promoting activity, as seen in the case of Frount-deficiency. Moreover, co-treatment with DSF and an immune checkpoint antibody synergistically inhibits tumor growth. Thus, inhibition of FROUNT by DSF represents a promising strategy for macrophage-targeted cancer therapy.

Genome-wide DNA methylation profiles in both precancerous conditions and clear cell renal cell carcinomas are correlated with malignant potential and patient outcome.

To clarify genome-wide DNA methylation profiles during multistage renal carcinogenesis, bacterial artificial chromosome array-based methylated CpG island amplification (BAMCA) was performed. Non-cancerous renal cortex tissue obtained from patients with clear cell renal cell carcinomas (RCCs) (N) was at the precancerous stage where DNA hypomethylation and DNA hypermethylation on multiple bacterial artificial chromosome (BAC) clones were observed. By unsupervised hierarchical clustering analysis based on BAMCA data for their N, 51 patients with clear cell RCCs were clustered into two subclasses, Clusters A(N) (n = 46) and B(N) (n = 5). Clinicopathologically aggressive clear cell RCCs were accumulated in Cluster B(N), and the overall survival rate of patients in Cluster B(N) was significantly lower than that of patients in Cluster A(N). By unsupervised hierarchical clustering analysis based on BAMCA data for their RCCs, 51 patients were clustered into two subclasses, Clusters A(T) (n = 43) and B(T) (n = 8). Clinicopathologically aggressive clear cell RCCs were accumulated in Cluster B(T), and the overall survival rate of patients in Cluster B(T) was significantly lower than that of patients in Cluster A(T). Multivariate analysis revealed that belonging to Cluster B(T) was an independent predictor of recurrence. Cluster B(N) was completely included in Cluster B(T), and the majority of the BAC clones that significantly discriminated Cluster B(N) from Cluster A(N) also discriminated Cluster B(T) from Cluster A(T). In individual patients, DNA methylation status in N was basically inherited by the corresponding clear cell RCC. DNA methylation alterations in the precancerous stage may generate more malignant clear cell RCCs and determine patient outcome.

Genome-wide DNA methylation profiles in liver tissue at the precancerous stage and in hepatocellular carcinoma.

To clarify genome-wide DNA methylation profiles during hepatocarcinogenesis, bacterial artificial chromosome (BAC) array-based methylated CpG island amplification was performed on 126 tissue samples. The average numbers of BAC clones showing DNA hypo- or hypermethylation increased from noncancerous liver tissue obtained from patients with hepatocellular carcinomas (HCCs) (N) to HCCs. N appeared to be at the precancerous stage, showing DNA methylation alterations that were correlated with the future development of HCC. Using Wilcoxon test, 25 BAC clones, whose DNA methylation status was inherited by HCCs from N and were able to discriminate 15 N samples from 10 samples of normal liver tissue obtained from patients without HCCs (C) with 100% sensitivity and specificity, were identified. The criteria using the 25 BAC clones were able to discriminate 24 additional N samples from 26 C samples in the validation set with 95.8% sensitivity and 96.2% specificity. Using Wilcoxon test, 41 BAC clones, whose DNA methylation status was able to discriminate patients who survived more than 4 years after hepatectomy from patients who suffered recurrence within 6 months and died within a year after hepatectomy, were identified. The DNA methylation status of the 41 BAC clones was correlated with the cancer-free and overall survival rates of patients with HCC. Multivariate analysis revealed that satisfying the criteria using the 41 BAC clones was an independent predictor of overall outcome. Genome-wide alterations of DNA methylation may participate in hepatocarcinogenesis from the precancerous stage, and DNA methylation profiling may provide optimal indicators for carcinogenetic risk estimation and prognostication.

Inactivation of beta1 integrin induces proteasomal degradation of Myc oncoproteins.

The MYC family oncogenes (MYC, MYCN, and MYCL) contribute to the genesis of many human cancers. Among them, amplification of the MYCN gene and over-expression of N-Myc protein are the most reliable risk factors in neuroblastoma patients. On the other hand, we previously found that a peptide derived from fibronectin, termed FNIII14, is capable of inducing functional inactivation in ß1-integrins. Here, we demonstrate that inactivation of ß1-integrin by FNIII14 induced proteasomal degradation in N-Myc of neuroblastoma cells with MYCN amplification. This N-Myc degradation by FNIII14 reduced the malignant properties, including the anchorage-independent proliferation and invasive migration, of neuroblastoma cells. An in vivo experiment using a mouse xenograft model showed that the administration of FNIII14 can inhibit tumor growth, and concomitantly a remarkable decrease in N-Myc levels in tumor tissues. Of note, the activation of proteasomal degradation based on ß1-integrin inactivation is applicable to another Myc family oncoprotein, c-myc, which also reverses cancer-associated properties in pancreatic cancer cells. Collectively, ß1-integrin inactivation could be a new chemotherapeutic strategy for cancers with highly expressed Myc. FNIII14, which is a unique pharmacological agent able to induce ß1-integrin inactivation, may be a promising drug targeting Myc oncoproteins for cancer chemotherapy.

Combining peptide TNIIIA2 with all-trans retinoic acid accelerates N-Myc protein degradation and neuronal differentiation in MYCN-amplified neuroblastoma cells.

Neuroblastoma is one of the common solid tumors of childhood. Nearly half of neuroblastoma patients are classified into the high-risk group, and their 5-year event-free survival (EFS) rates remain unsatisfactory in the range of 30-40%. High-risk neuroblastoma is characterized by amplification of the MYCN gene and excessive expression of its protein product, N-Myc. Because N-Myc is a transcription factor for various pro-proliferative proteins, the excessive expression causes aberrant or blocked neuronal differentiation during development of sympathetic nervous system, which is a central aspect of neuroblastoma genesis. The current main treatment for high-risk neuroblastoma is intensive chemotherapy using anti-cancer drugs that induce apoptosis in tumor cells, but intensive chemotherapy has another serious risk of long-lasting side effects, so-called "late effects", that occur many years after chemotherapy has ended. As a solution for such situation, differentiation therapy has been expected as a mild chemotherapy with a low risk of late effects, and an application of retinoic acid (RA) and its derivatives as treatment for high-risk neuroblastoma has long been attempted. However, the clinical outcome has not been sufficient with the use of retinoids, including all-trans retinoic acid (ATRA), mainly because of the inhibition of differentiation caused by N-Myc. In the present study, we succeeded in synergistically accelerating the ATRA-induced neuronal differentiation of MYCN-amplified neuroblastoma cells by combining a peptide derived from tenascin-C, termed TNIIIA2, which has a potent ability to activate ß1-integrins. Accelerated differentiation was caused by a decrease in N-Myc protein level in neuroblastoma cells after the combined treatment of TNIIIA2 with ATRA. That is, combination treatment using ATRA with TNIIIA2 induced proteasomal degradation in the N-Myc oncoprotein of neuroblastoma cells with MYCN gene amplification, and this caused acceleration of neuronal differentiation and attenuation of malignant properties. Furthermore, an in vivo experiment using a xenograft mouse model showed a therapeutic potential of the combination administration of ATRA and TNIIIA2 for high-risk neuroblastoma. These results provide a new insight into differentiation therapy for high-risk neuroblastoma based on N-Myc protein degradation.

Frequent silencing of the candidate tumor suppressor PCDH20 by epigenetic mechanism in non-small-cell lung cancers.

Protocadherins are a major subfamily of the cadherin superfamily, but little is known about their functions and intracellular signal transduction. We identified a homozygous loss of protocadherin 20 (PCDH20, 13q21.2) in the course of a program to screen a panel of non-small-cell lung cancer (NSCLC) cell lines (1 of 20 lines) for genomic copy number aberrations using an in-house array-based comparative genomic hybridization. PCDH20 mRNA was expressed in normal lung tissue but was not expressed in the majority of NSCLC cell lines without a homozygous deletion of this gene (10 of 19 lines, 52.6%). Expression of PCDH20 mRNA was restored in gene-silenced NSCLC cells after treatment with 5-aza 2'-deoxycytidine. The DNA methylation status of the PCDH20 CpG-rich region correlated inversely with the expression of the gene and a putative target region for methylation showed clear promoter activity in vitro. Methylation of this PCDH20 promoter was frequently observed in primary NSCLC tissues (32 of 59 tumors, 54.2%). Among our primary NSCLC cases, the methylated PCDH20 seemed to be associated with a shorter overall survival (P = 0.0140 and 0.0211 in all and stage I tumors, respectively; log-rank test), and a multivariate analysis showed that the PCDH20 methylation status was an independent prognosticator. Moreover, restoration of PCDH20 expression in NSCLC cells reduced cell numbers in colony formation and anchorage-independent assays. These results suggest that epigenetic silencing by hypermethylation of the CpG-rich promoter region of PCDH20 leads to loss of PCDH20 function, which may be a factor in the carcinogenesis of NSCLC.

Ceritinib Treatment for Carcinomatous Meningitis with a Secondary Mutation at I1171T in Anaplastic Lymphoma Kinase.

The mechanisms underlying anaplastic lymphoma kinase (ALK) resistance have not been well investigated in clinical practice. We herein report the case of a lung cancer patient with carcinomatous meningitis who had an ALK I1171T resistance mutation revealed by direct DNA sequencing of the cerebrospinal fluid after treatment with cytotoxic chemotherapy, crizotinib, and alectinib. I1171T is considered to be sensitive to ceritinib. Although ceritinib was not effective initially, we chose ceritinib again after whole-brain radiotherapy and ventriculoperitoneal shunting. Although the response duration was short, spinal magnetic resonance imaging revealed a marked response. The identification of an acquired ALK resistance mutation will aid in choosing the optimum sequence therapy.