Prognostic significance of classified extramural tumor deposits and extracapsular lymph node invasion in T3-4 colorectal cancer: a retrospective single-center study.

BACKGROUND: Extramural tumor deposits (TDs) and extracapsular lymph node involvement (ECLNI) are considered to be poor prognostic factors in patients with T3-4, N0-2, M0 colorectal cancer (CRC). Although TDs are known to have multiple origins and pleomorphic features, the prognostic significances of the different type of TDs have not yet been established. METHODS: We performed a retrospective review of 385 consecutive patients with T3-4, N0-2, M0 CRC who received curative resection at our institution between 2006 and 2012. We classified the TDs into two groups: invasive-type TD (iTD), which is characterized by the presence of lymphatic invasion, vascular invasion, perineural invasion, or undefined cancer cell clusters and nodular-type TD (nTD), which is characterized by a smooth or irregular-shaped tumor nodule other than an iTD. ECLNI was defined as invasion of cancer cells into capsular collagen tissues or adipose tissues beyond the capsular collagen. Multivariate analyses were used to assess the prognostic significance of iTD, ND, and ECLNI for relapse-free survival (RFS), disease-specific survival (DSS), and sites of recurrence. RESULTS: In patients without lymph node (LN) metastasis, the incidences of iTD and nTD were both in the range of 2-3 %. Conversely, in patients with LN metastasis, the incidences of iTD, nTD, and ECLNI were 31, 22, and 34 %, respectively. iTD, nTD, and ECLNI were all significant independent adverse factors for RFS in rectal cancer, and were all associated with pT, pN, and LN ratio. iTD was a significant independent adverse prognostic factor for DSS in rectal cancer, metastasis to the liver in colorectal cancer, and distant LN metastasis in colon cancer. ECLNI was a significant independent prognostic factor for RFS in colon cancer. CONCLUSIONS: Classifying TDs and assessing ECLNI may help establish significant prognostic factors for patients with T3-4, N0-2, M0 CRC.

Sorting Nexin 2 (SNX2): a potential marker of active thyrocytes in normal and hyperfunctioning thyroid disorders.

Sorting nexins (SNXs) are a large, diverse group of cytoplasmic and membrane-associated proteins that function in a variety of cellular processes, including endocytosis, protein trafficking, and the retrieval of transmembrane proteins. In this study, we demonstrated that SNX2 is expressed in columnar and active thyroid follicular cells but not in flattened inactive thyrocytes. Morphometric analysis revealed a significant correlation between SNX2 positivity and columnar cell morphology. Immunohistochemical staining of serial sections of the thyroid tissue indicated that SNX2 localization was similar to sortilin, a protein expressed by active thyrocytes. Expression of SNX2 in thyrocytes is particularly marked and extensive in most hyperstimulated thyroid disorders, including Graves disease (diffusely SNX2 positive in 73.3% patients) and functioning nodules (93.8% patients). SNX2 immunolocalization in hyperstimulated follicular epithelial cells was specific among the SNXs family members examined. These results support the utility of SNX2 as a novel marker of active thyrocytes and reflect the endosomal trafficking activity in these cells.

Pathogenesis of combined high-grade squamous intraepithelial lesion and adenocarcinoma in situ of the uterine cervix: human papillomavirus genotype and methylation status and immunohistochemical study.

To determine the etiology of combined high-grade squamous intraepithelial lesion (HSIL) and adenocarcinoma in situ (AIS) of the uterine cervix, we examined human papillomavirus (HPV) subtypes, methylation status of the HPV-16 L1 gene, and immunohistochemical staining pattern of Krt7 in 8 cases of combined HSIL and AIS. Overall, 6 (75%) of 8 patients with combined HSIL and AIS were infected by the same subtype of HPV in both HSIL and AIS (cases 1-5, HPV-16; and case 6, HPV-18), whereas 2 (25%) patients showed infection with different subtypes of HPV (case 7, HPV-31 and -18; and case 8, HPV-52 and -16, in HSIL and AIS, respectively). The degrees of methylation at CpG islands within the HPV-16 L1 gene were almost equivalent between HSIL and AIS in cases 1-4, whereas a great difference in CpG methylation patterns between two was seen in only 1 case (case 5). In addition, both patients infected with different subtypes of HPV between HSIL and AIS were positive for Krt7 only within the AIS component. Based on these results, we propose two distinct developmental pathways of combined HSIL and AIS of the uterine cervix, the common pathway and the individual pathway.

Tumor associated macrophage expressing CD204 is associated with tumor aggressiveness of esophageal squamous cell carcinoma.

Tumor associated macrophages (TAMs) are the most abundant cancer stromal cells educated by tumor microenvironment to acquire trophic functions facilitating angiogenesis, matrix breakdown and cancer cell motility. Tumor associated macrophages have anti-inflammatory properties or "alternatively" activated (M2) phenotype expressing CD204 and/or CD163. To know the role of TAMs in the growth and progression of esophageal squamous cell carcinomas (ESCCs), we calculated intratumoral CD204, CD163 or CD68 expressing macrophage count (MϕC) and CD34-positive microvessel density (MVD) by immunohistochemistry in 70 cases of surgically resected ESCCs and compared them with the clinicopathological factors and prognosis of patients. MϕC had positive linear association with MVD. High CD204(+) MϕC were significantly correlated with more malignant phenotypes including depth of tumor invasion, lymph and blood vessel invasion, lymph node metastasis as well as clinical stages. On the other hand, CD163(+) MϕC did not associate with these clinicopathological factors with the exception of depth of tumor invasion and blood vessel invasion. Patients with high CD204(+) MϕC ESCCs showed poor disease-free survival (P = 0.021). Conditioned media of five ESCC cell lines (TE-8, -9, -10, -11 and -15) induced mRNA as well as protein expression of CD204 but not of CD163 with upregulation of vascular endothelial growth factor-A mRNA in TPA treated human acute monocytic leukemia cell line THP-1. These results overall indicate that CD204 is a useful marker for TAMs contributing to the angiogenesis, progression and prognosis of ESCCs whose specific tumor microenvironment may educate macrophages to be CD204(+) M2 TAMs.

WNT5A is a key regulator of the epithelial-mesenchymal transition and cancer stem cell properties in human gastric carcinoma cells.

OBJECTIVE: Direct interaction with cancer-associated fibroblasts triggers WNT5A expression in human gastric carcinoma (GC) cells. In this study, we performed gene transduction experiments to investigate the significance of WNT5A in the GC tumor microenvironment. METHODS: Gene transduction (pWNT5A and shWNT5A) was performed in human GC-derived MKN-7 cells. Altered gene expression was examined by RT-PCR and cDNA microarray analysis. Immunohistochemical examination was carried out in human GC tissues. RESULTS: Transduction of exogenous WNT5A expression into MKN-7 cells upregulated genes related to the epithelial-mesenchymal transition (EMT) and cancer stem cells (CSCs), and the pWNT5A transfectant showed high tumorigenicity in vivo. These results were confirmed by knockdown experiments using a lentivirus expressing shWNT5A. A cDNA microarray analysis suggested that depletion of endogenous WNT5A downregulated genes involved in intracellular signaling, chemokine-cytokine interaction and focal adhesion. High levels of WNT5A expression were observed in 66% of GC cases, with significant correlation with histological type. Interestingly, in intestinal-type GCs, WNT5A expression was detected in the periphery of tumor nests. CONCLUSIONS: WNT5A regulates the induction of EMT and the maintenance of CSC properties in MKN-7 cells. WNT5A may play an important role in constructing an advantageous tumor microenvironment for the progression and development of human GC.

Second trimester fetal death caused by varicella-zoster virus infection.

A 31-year-old woman contracted acute varicella at 13 weeks of gestation. Severe hydrops fetalis, hepatomegaly, and intrauterine fetal death were detected at 16 weeks of gestation by ultrasound examinations. An examination at autopsy, histopathology, and polymerase chain reaction (PCR) provided evidence of varicella-zoster virus (VZV) infection of the fetus. Second trimester intrauterine fetal death caused by mother to fetus infection of VZV is extremely rare.

Cdx2 expression and its promoter methylation during metaplasia-dysplasia-carcinoma sequence in Barrett's esophagus.

AIM: To examine how the expression of caudal type homebox transcription factor 2 (Cdx2) is regulated in the development of malignancy in Barrett's esophagus. METHODS: Cdx2, mucin (MUC) series (MUC2, MUC5AC and MUC6), p53 and E-cadherin expression in Barrett's esophagus and adenocarcinoma specimens were examined by immunostaining. Isolated clusters of cells from (1) MUC2 and Cdx2-positive intestinal metaplastic mucosa; (2) MUC5AC and MUC6-positive, and MUC2 and Cdx2-negative high-grade dysplasia (HD), or intramucosal adenocarcinoma (IMC); and (3) MUC5AC, MUC6 and Cdx2-positive poorly-differentiated invasive adenocarcinoma (PDA) were analyzed by methylation-specific polymerase chain reaction using sets of primers for detecting methylation status of the Cdx2 gene. RESULTS: Most of the non-neoplastic Barrett's esophageal mucosa showing intestinal-type metaplasia with or without low-grade dysplasia was positive for E-cadherin, MUC series and Cdx2, but negative for p53. A portion of the low-grade to HD was positive for E-cadherin, MUC5AC, MUC6 and p53, but negative for MUC2 and Cdx2. The definite IMC area was strongly positive for MUC5AC, MUC6 and p53, but negative for MUC2 and Cdx2. Methylation of the Cdx2 promoter was not observed in intestinal metaplasia, while hypermethylation of part of its promoter was observed in hot dipped and IMC. Hypermethylation of a large fraction of the Cdx2 promoter was observed in PDA. CONCLUSION: Cdx2 expression is restored irrespective of the methylation status of its promoter. Apparent positive immunohistochemical results can be a molecular mark for gene silencing memory.

Jejunal tubulovillous adenocarcinoma in adenoma presenting with entero-enteric intussusception.

A 73-year-old male was admitted to our institution with complaints of nausea, vomiting, and abdominal distension. Plain abdominal computed tomography (CT) suggested intussusception in the jejunum. Enhanced abdominal CT revealed the 'target-like' sign and ultrasonography revealed the 'multiple concentric ring' sign; therefore, a diagnosis of entero-enteric intussusception was made. The small intestinal obstruction and cause of the intussusception were not evident. The patient was treated conservatively with fasting and transfusion therapy to prevent intestinal obstruction. However, with no spontaneous resolution of intussusception, surgical treatment was decided. The operative findings revealed a jejunal tumor about 30 cm from the Treiz ligament, and the jejunum including the tumor with a 5 cm margin were partially resected. The resected tumor was a 35 × 50 mm soft mass spreading laterally with nodules. The pathological examinations revealed tubulovillous adenocarcinoma in the adenoma. Intussusception is rare in adults compared to children. About 45 % of cases of intussusception in adults are due to small intestinal tumors such as malignant lymphoma or lipoma, but a tubulovillous adenocarcinoma with adenoma is a rare cause of intussusception. We present a rare case of jejunal tubulovillous adenocarcinoma in adenoma presenting with entero-enteric intussusception.

[A case of intestinal obstruction occurring during anti-tuberculous therapy for tuberculous peritonitis].

We report here a case of intestinal obstruction occurring during anti-tuberculous therapy for tuberculous peritonitis. An 89-year-old woman, who had been treated for tuberculous spondylitis and operated for tuberculous mastitis and peritonitis, was transferred to our hospital with high grade fever, lower abdominal pain and vomiting. An enhanced abdominal computed tomography (CT) revealed ascites and hypertrophy of the parietal peritoneum. Puncture and drainage of ascites were performed and revealed that a smear examination of the specimen was positive for acid-fast bacilli (Gaffky 1). Treatment by rifampicin, isoniazid and ethambutol for tuberculous peritonitis was started then halted because of drug-induced liver injury. After recovery of the liver damage improved, anti-tuberculosis drugs (rifampicin and streptomycin) were restarted. However two days after recommencing administration, repeated vomiting occurred. An abdominal X-ray showed intestinal obstruction. An ileus tube was inserted and she was treated conservatively, but her symptoms did not improve. Injection of contrast medium through the ileus tube showed obstruction of the upper jejunum, so open surgery was performed. Disseminated yellowish miliary tubercles were seen on the peritoneum and severe inflammatory adhesions were found between the jejunum and the ileum. After ablation of the adhesions, partial resections of jejunum and ileum were performed. Histological examination confirmed the diagnosis of tuberculous peritonitis.

Mesenchymal stem cells provide an advantageous tumor microenvironment for the restoration of cancer stem cells.

OBJECTIVE: Accumulating evidences suggest that cancer-associated fibroblasts are provided from bone-marrow-derived mesenchymal stem cells (BM-MSCs); however, little is known about the mechanism(s) by which BM-MSCs accelerate cancer aggressiveness. METHODS: Gastric carcinoma (GC)-derived MKN-7 cells were cocultured with UE6E7T-12 BM-MSCs. The gene expression profile in MKN-7 cells was investigated by microarray analysis. Between two major types of GCs (intestinal- and diffuse-type), the expression of genes was detected by immunohistochemistry. RESULTS: We found that direct attachment to UE6E7T-12 induced proliferation and cluster formation of MKN-7 cells. Coculture with UE6E7T-12 increased the population of CD133+ MKN-7 cells in vitro and coimplantation of these in mice resulted in subcutaneous tumors in vivo. The wingless-type MMTV integration site (WNT) family member 5A (WNT5A) and transforming growth factor-ß (TGF-ß)-induced (TGFBI) genes were found to be upregulated in MKN-7 cells directly attached to UE6E7T-12. Recruitment of CD271+ BM-MSC was detected preferentially in the stroma of the diffuse-type GC and this type of GC cell also showed frequent expression of WNT5A, TGF-ß type I receptor and CD133. CONCLUSION: BM-MSC-mediated activations of the WNT and TGF-ß signaling pathways were thought to provide advantageous microenvironments for cancer progression by supporting the reacquisition and maintenance of cancer stem cells.

Biological significance of tumor budding at the invasive front of human colorectal carcinoma cells.

At the invasive front of colorectal carcinoma (CRC), the existence of tumor budding (TB), the detachment and migration of small clusters of tumor cells from the neoplastic epithelium, correlates with high incidence of local invasion and distant metastasis; however, the molecular background of TB is still unknown. In human CRC-derived SW480 cells, CD133+ cells showed cancer stem cell (CSC)-like properties, high tumorigenicity and pluripotency. By a comparative study of gene expression between CD133+ and CD133- SW480 cells, high sensitivity against transforming growth factor-ß (TGF-ß) was suggested in CD133+ SW480 cells. Interestingly, treatment with recombinant TGF-ß1 increased the numbers of cells expressing CD133 and SNAI1. Furthermore, in CD133- SW480 cells, the SNAI1-induced epithelial-mesenchymal transition (EMT) restored the population of CD133+ cells and increased tumorigenicity, cell motility/invasiveness and matrix metalloproteinase 2 (MMP2) expression. In stage II CRC tissues, TB was associated with increased levels of SNAI1 expression as well as high incidence of metachronous lymph node metastasis post-surgical resection. These findings suggest that TGF-ß regulates not only the induction of EMT but also the restoration of CSCs in CRC. The tumor microenvironment at the invasive front is important for the formation of tumor buds in CRC.

Hypoxia induces tumor aggressiveness and the expansion of CD133-positive cells in a hypoxia-inducible factor-1α-dependent manner in pancreatic cancer cells.

BACKGROUND: Intratumoral hypoxia is known to lead to increased aggressiveness and distant metastasis. However, the interplay underlying these actions is still unknown. OBJECTIVE: We explored whether cancer cells might acquire a stem-like phenotype under hypoxia, consequently leading to an aggressive phenotype, including invasiveness and metastasis. METHODS: Under normoxia (20% O(2)) or hypoxia (1% O(2)), the expression of CD133 (cancer stem cell marker), CXC chemokine receptor 4 (CXCR4) and hypoxia-inducible factor-1α (HIF-1α) was examined by RT-PCR and immunostaining using human pancreatic cancer cell lines. We also examined if hypoxia facilitates the invasiveness of CD133+ cancer cells. Furthermore, we transfected dominant active HIF-1α (HIF-1αΔODD) by the retroviral gene transfer and examined the effects both in vitro and in vivo. RESULTS: Compared with normoxia, hypoxia elevated the expression of CD133, CXCR4 and HIF-1α. Moreover, hypoxia facilitated the invasiveness of CD133+ pancreatic cancer cells. The behavior of HIF-1αΔODD-transfected cells under normoxia was compatible with that of the parent cells under hypoxia. Furthermore, a xenograft model of HIF-1αΔODD cells showed aggressiveness, including metastasis and highly tumorigenic ability. CONCLUSION: Hypoxia induces tumor aggressiveness associated with the expansion of CD133+ pancreatic cancer cells in a predominantly HIF-1α-dependent manner.

Requirement of phosphatase of regenerating liver-3 for the nucleolar localization of nucleolin during the progression of colorectal carcinoma.

Phosphatase of regenerating liver-3 (PRL-3) is a protein tyrosine phosphatase (PTP) that is frequently overexpressed in liver metastases of colorectal carcinomas (CRCs). The PTP activity of the PRL-3 protein is indispensable for the promotion of distant metastasis of CRC; however, little is known about the effect of PRL-3 on cell growth. In this study, we investigated a novel protein that can connect to PRL-3 to modulate the proliferation of CRC cells. In CRC-derived SW480 cells, transduction of ectopic wild-type PRL-3, but not the C104S catalytic "dead" mutant, up-regulated cell proliferation and increased the population of cells at the S and G(2) /M phases. Also, inhibition of PTP activity of the PRL-3 protein by treatment with the PRL-3 inhibitor suppressed cell proliferation in a dose-dependent manner as well as PRL-3 knockdown by RNA interference. Using a comparative study of monodimensional gel electrophoresis of immunoprecipitates from PRL-3-transfected SW480 cells and subsequent mass spectrometry analysis, nucleolar-specific protein nucleolin (NCL) was identified as a novel PRL-3-binding protein. We confirmed physiological interaction between PRL-3 and NCL, and found that PRL-3 phosphatase activity was associated with the suppression of the phospho-NCL levels and nucleolar assembly of NCL protein. In CRC cases, nucleolar NCL expression was correlated not only with higher levels of PRL-3 expression but also with frequent incidence of lymph node metastasis and a higher clinicopathologic stage. These findings suggest that NCL is involved in PRL-3-mediated cancer progression/metastasis signaling, which plays an important role in the acceleration of CRC growth.

Loss of WW domain-containing oxidoreductase expression in the progression and development of gastric carcinoma: clinical and histopathologic correlations.

The purpose of this study is to investigate the role of the WW domain-containing oxidoreductase (WWOX) tumor suppressor that maps to the common fragile site FRA16D (16q23.3-24.1) during the development of gastric carcinoma (GC), we examined the altered expression of WWOX in GC cell lines and tissue samples as well as the effects of restoration of the WWOX gene into WWOX-deficient GC cells. All GC cell lines (HSC-45, HSC-57, HSC-59, MKN-7, and MKN-74) showed reduced WWOX expression at the mRNA and protein levels and hypermethylation at the WWOX regulatory site was detected in HSC-45 and HSC-59 cells. Interestingly, treatment with the deacetylating agent trichostatin A and the demethylating agent 5-aza-2'-deoxycytidine restored endogenous WWOX expression levels in HSC-59 cells. Restoration of the WWOX gene with Ad-WWOX into HSC-59 cells effectively suppressed cell growth and increased the population of cells in subG(1) DNA content. In GC tissue samples, the loss of WWOX expression was detected in 24 (33%) of 73 GC cases in accordance with the hypermethylation at the WWOX regulatory site. Surprisingly, negative immunoreactivity against WWOX showed a significant relationship with several clinicopathologic findings, including histology (P = 0.0001), depth of invasion (P = 0.0004), lymph node metastasis (P = 0.0003), vessel infiltration (lymphatic vessels, P = 0.0167 and venous vessels, P = 0.0005), and clinicopathologic stage (P = 0.001). These findings suggest that repression of WWOX expression may play an important role in stomach carcinogenesis. WWOX thus appears to be a good biomarker for molecular diagnosis of the grade of malignancy of GCs.

Constitutive suppression of PRL-3 inhibits invasion and proliferation of gastric cancer cell in vitro and in vivo.

OBJECTIVE: Overexpression of phosphatase of regenerating liver-3 (PRL-3) has been implicated in tumor progression and metastasis of gastric carcinoma. Here we examined what alterations occur in the phenotype of gastric cancer cells in vitro and in vivo when PRL-3 expression is knocked down. METHODS: We constructed a small interfering RNA (siRNA)-expressing vector which stably interfered with PRL-3 expression and was transfected into SH101-P4 cells, which express the highest PRL-3 mRNA levels among 13 gastric cancer cell lines. The new SH101-P4 subclones, in which PRL-3 was stably reduced, were established and their in vitro growth, motility and abilities of liver metastasis from the injected spleen were analyzed in vivo. RESULTS: PRL-3 knockdown effectively suppressed invasion and growth of SH101-P4 cells in vitro. Liver metastasis in vivo was significantly decreased when PRL-3 expression was suppressed. The primary tumor size in the injected spleen tended to be smaller in PRL-3 knockdown clones than in the controls. These findings suggest that PRL-3 expression may contribute not only to the establishment of metastasis but also to the growth of primary foci of human gastric cancer. Therefore, PRL-3 may be one of the target molecules in gastric cancer therapy.

Negative regulation of the tight junction protein tricellulin by snail-induced epithelial-mesenchymal transition in gastric carcinoma cells.

OBJECTIVE: Tricellulin plays a central role in the sealing of epithelia at tricellular contacts. We examined the effects of Snail, an epithelial-mesenchymal transition (EMT)-related transcription factor, on the regulation of tricellulin expression in human gastric carcinoma (GC)-derived cells. METHOD: Six human GC-derived cell lines were used in this study. Expression and localization of tricellulin was analyzed by reverse transcription (RT)-PCR and immunohistochemistry. Also, a Snail expression vector was transfected into HSC-45 cells to examine altered mRNA levels of tricellulin,E-cadherin, vimentin, N-cadherin and several EMT transcription factors by quantitative real-time RT-PCR. RESULTS: Abundant tricellulin expression was detected in all GC-derived cells examined. In HSC-45 cells, transduction of Snail decreased the expression levels of tricellulin and E-cadherin but increased vimentin and N-cadherin, which was accompanied by induction of EMT transcription factors such as Twist1, Twist2 and Slug. In normal gastric mucosa, tricellulin protein was localized at the tricellular tight junction; however, in HSC-45 cells, tricellulin protein was distributed in the cytoplasm. In GC tissues, tricellulin expression at the cellular membrane was retained in a subset of EMT-negative GCs, and it disappeared in EMT-positive GCs. CONCLUSIONS: The findings in the present study suggest that repression of tricellulin expression may be related to Snail-induced EMT in human GCs.

Superficially elevated-type serrated hyperplastic lesion of the stomach with minute adenocarcinoma.

We report a case of gastric serrated hyperplastic lesion with minute adenocarcinoma. A 65-year-old Japanese man underwent endoscopic submucosal dissection to the superficially elevated-type (0-IIa) lesion located at the lesser curvature of the gastric angle. Histological observation revealed hyperplastic change of foveolar epithelium with serrated glandular structure as well as a minute tubular adenocarcinoma component. Immunohistochemically, the lesion demonstrated gastrointestinal, predominantly gastric, phenotype (MUC5AC++, MUC6+, MUC2+, CD10-). Positive p53 immunoreactivity was detected in the carcinoma component of the lesion with a point mutation (G877T; R209I) of the gene and microsatellite instability of the BAT-RII locus; however, immunoreactivity of the mismatch repair gene product hMLH1 was well preserved in the cancer as well as in the hyperplastic lesion. The hyperplastic lesion with serrated glandular pattern would be a precancerous lesion of adenocarcinoma of the stomach.

Alternative lengthening of telomeres frequently occurs in mismatch repair system-deficient gastric carcinoma.

Maintenance of telomeric ends by the telomerase ribonucleoprotein complex or the telomerase-independent alternative lengthening of telomeres is necessary for the immortalization of human cells. The significance of alternative lengthening of telomeres has been suggested in DNA mismatch repair system-deficient cells; however, much remains unknown in human malignancies. In this study, we investigated the telomere maintenance mechanism in gastric carcinoma. In formalin-fixed and paraffin-embedded sections of the high frequency of microsatellite instability (MSI-H) and non-MSI-H gastric carcinomas, there was no difference in telomere length monitored by telomere intensity ratio using telomere-fluorescent in situ hybridization. Immunoreactivity of hTERT, the catalytic subunit of telomerase, was detected in 48% of MSI-H gastric carcinomas. The frequency was significantly lower than that in non-MSI-H gastric carcinomas (86%, P = 0.02). Conversely, the number of the alternative lengthening of telomeres-associated promyelocytic leukemia bodies (APBs) detected by combined promyelocytic leukemia immunofluorescence and telomere-fluorescent in situ hybridization was statistically higher (57%) in the MSI-H gastric carcinomas compared to that in non-MSI-H gastric carcinomas (19%, P = 0.026). The cases with hTERT(+)APBs(-) were more frequent in non-MSI-H gastric carcinomas (76%) than in MSI-H gastric carcinomas (24%), and the cases with hTERT(-)APBs(+) were more frequent in MSI-H gastric carcinomas (33%) than in non-MSI-H gastric carcinomas (10%). These results suggest that alternative lengthening of telomeres-mediated telomere maintenance plays an important role for microsatellite instability-mediated stomach carcinogenesis, as well as the telomerase ribonucleoprotein complex, although the incidence of MSI-H is low. Defects of the mismatch repair system may lead to homeologous recombination of telomeric ends for the telomerase-independent telomere maintenance in gastric carcinomas.

Down-modulation of keratin 8 phosphorylation levels by PRL-3 contributes to colorectal carcinoma progression.

Phosphatase of regenerating liver-3 (PRL-3) is a member of the PRL protein tyrosine phosphatase family and has been proposed to promote the invasiveness and metastastic capability of colorectal cancers (CRCs); however, the underlying mechanisms and target molecules of PRL-3 protein remain unknown. On the basis of the biological significance of PRL-3 phosphatase activity confirmed by the catalytically inactive PRL-3 mutant (C104S) and a PRL-3 inhibitor in CRC-derived SW480 cells, we performed protein expression profiling to search for PRL-3-mediated effector proteins. By a comparative study of phosphorylated proteins that differentially expressed in wild type and C104S mutant PRL-3-transfected SW480 cells; the cytoskeletal intermediate filament keratin 8 (KRT8) was identified as a physiological PRL-3-interacting protein. Indeed, treatment with the PRL-3 inhibitor effectively suppressed the phosphorylation of KRT8 at S73 and S431. Moreover, we detected the physiological interaction between PRL-3 and KRT8 and their colocalization at cellular lamellipodias and ruffles in vivo. In CRC tissue samples, tumor cells with high PRL-3 expression showed reduction or loss of phosphorylated KRT8 expression, particularly at the invasive front and in the liver metastases. In conclusion, our results indicate that PRL-3 may play an important role for the promotion of CRC cell migration and metastatic potential through direct KRT8 dephosphorylation.