Suppression of pancreatic cancer growth and metastasis by HMP19 identified through genome-wide shRNA screen.

Therapeutic effectiveness against metastatic or even locally advanced pancreatic ductal adenocarcinoma (PDAC) is dismal, with 5-year survival less than 5%. Even in patients who undergo potentially curative resection, most patients' tumors recur in the liver. Improving therapies targeting or preventing liver metastases is crucial for improving prognosis. To identify genes suppressing metastasis, a genome-wide shRNA screen was done using the human non-metastatic PDAC cell line, S2-028. After identification of candidates, functional validation was done using intrasplenic and orthotopic injections in athymic mice. HMP19 strongly inhibited metastasis but also partially attenuated tumor growth in the pancreas. Knockdown of HMP19 increased localization of activated ERK1/2 in the nucleus, corresponding to facilitated cell proliferation, decreased p27(Kip1) and increased cyclin E1. Over-expression of HMP19 exerted the opposite effects. Using a tissue microarray of 84 human PDAC, patients with low expression of HMP19 showed significantly higher incidence of liver metastasis (p = 0.0175) and worse prognosis (p = 0.018) after surgery. HMP19, a new metastasis/tumor suppressor in PDAC, appears to alter signaling that leads to cell proliferation and appears to offer prognostic value in human PDAC.

The clinical usefulness of the intraoperative detection of sentinel lymph node metastases by a rapid RT-PCR system in patients with gastric cancer.

BACKGROUND: The incidence of pathological lymph node metastases in patients with gastric cancer is 5% to 10%, which means that approximately 90% of patients with gastric cancer may undergo unnecessary lymphadenectomy. The precise intraoperative diagnosis of sentinel lymph node (SN) metastases is essential. The purpose of the current study was to verify the usefulness of a rapid reverse transcriptase-polymerase chain reaction (RT-PCR) system compared with hematoxylin and eosin staining for such diagnoses. METHODS: A total of 113 patients with clinical T1-T2 (cT1-T2) gastric cancer, including 73 patients with cT1cN0 disease with a tumor diameter <4 cm, were enrolled in the current study. SNs were identified by a radioisotope method. Carcinoembryonic antigen and cytokeratin 19 were used as markers for RT-PCR and the cutoff values were set using 1701 lymph nodes harvested from 157 patients with gastric cancer. RESULTS: SNs were detected in all 113 patients. Sensitivity and accuracy for detection by paraffin section were both 100% in patients with cT1 disease and were 60% and 90%, respectively, in patients with cT2 disease. The sensitivity of RT-PCR for the detection of pathological SN metastases was 92.3%. Furthermore, 11 patients had SN metastases detected only by RT-PCR, and these patients had frequent lymphatic invasion. Hematoxylin and eosin staining detected SN metastases in 6 of 73 patients with cT1cN0 gastric cancer; RT-PCR and frozen section detected SN metastases in 6 and 4 of these patients, respectively. Accordingly, the sensitivity of RT-PCR and frozen section for the detection of those pathological SN metastases were 100% and 66.6%, respectively. CONCLUSIONS: The rapid RT-PCR system appears to have clinical usefulness for the intraoperative detection of SN metastases in patients with gastric cancer.

Clinical Significance of Circulating Tumor Cells in Peripheral Blood of Patients with Esophageal Squamous Cell Carcinoma.

BACKGROUND: Esophageal squamous cell carcinoma is an aggressive gastrointestinal tract cancer. To date, the presence of circulating tumor cells (CTC) has been reported as a prognostic factor in peripheral blood from patients with gastrointestinal cancers. METHODS: The CellSearch system was used to isolate and enumerate CTCs. A total of 90 patients with esophageal squamous cell carcinoma who received chemotherapy or chemoradiotherapy were enrolled. Peripheral blood specimens were collected before and after treatments. RESULTS: At baseline analysis, CTCs were detected in 25 patients (27.8 %). Overall survival was significantly shorter in patients with than without CTCs. Follow-up blood specimens were obtained from 71 patients. Partial response, stable disease, and progressive disease after treatment were seen in 32, 12, and 27 patients, respectively. CTC positivity after treatment in the progressive disease group (40.7 %) was significantly higher than that of the partial response group (6.3 %). Patients with a change in CTC status from positive to negative had a good prognosis as well as patients without baseline CTCs. CONCLUSIONS: Evaluation of CTCs may be a promising indicator for predicting tumor prognosis and the clinical efficacy of chemotherapy or chemoradiation therapy in patients with esophageal squamous cell carcinoma.

Clinicopathological significance of nuclear factor (erythroid-2)-related factor 2 (Nrf2) expression in gastric cancer.

BACKGROUND: The transcription factor nuclear factor (erythroid-2)-related factor 2 (Nrf2) was originally identified as a critical regulator of intracellular anti-oxidants and of phase II detoxification enzymes through its transcriptional up-regulation of many anti-oxidant response element (ARE)-containing genes. Nrf2 protects not only normal cells but also cancer cells from cellular stress, and enhances cancer cell survival. Some studies have shown that Nrf2 expression in cancer patients has clinical significance. However, there has been no comprehensive analysis of the nuclear expression level of Nrf2 in gastrointestinal cancer cells. In this study we aimed to immunohistochemically evaluate the expression of Nrf2, and to assess its clinical significance in gastric cancer. METHODS: A total of 175 gastric cancer patients who received R0 gastrectomy with standard lymph node dissection were enrolled. We immunohistochemically evaluated Nrf2 expression in the paraffin-embedded surgically resected specimens of these 175 patients. Group differences were analyzed using the χ (2) test, Fisher's exact test, and the Mann-Whitney U test. Associations between Nrf2 expression and clinicopathological features, including clinical outcome, were assessed using univariate and multivariate analyses, and Kaplan-Meier curves with the log-rank test, respectively. RESULTS: Nrf2 immunoreactivity was predominantly identified in the nucleus of gastric cancer cells. Nrf2 positivity was closely associated with tumor size, tumor depth, lymph node metastases, lymphovascular invasion, histology and stage (p < 0.05 for all). A log-rank test indicated that the overall survival of the Nrf2-positive group was significantly poorer than that of the Nrf2-negative group (p < 0.01). And, positive Nrf2 expression was significantly associated with resistance to 5FU-based adjuvant chemotherapy (p = 0.024). CONCLUSIONS: Nrf2 expression was positively associated with aggressive tumor behavior in gastric cancer. This result suggests that Nrf2 expression in gastric cancer is a potential indicator of worse prognosis.

Clinical-pathological implication of human leukocyte antigen-F-positive gastric adenocarcinoma.

BACKGROUND: Human leukocyte antigen (HLA)-F is a nonclassical HLA class I molecule that shows aberrant expression in cancer cells. Although the clinical implications of HLA-F expression in cancer patients have been described, the specific significance of this antigen in gastrointestinal cancer remains unclear. The present study examined the expression pattern and clinical implications of HLA-F in gastric adenocarcinoma. PATIENTS AND METHODS: HLA-F expression was assessed in 179 patients by immunohistochemistry, and its association with clinical parameters including patient survival was analyzed. RESULTS: HLA-F expression was positive in 30.7% (55/179) of patients and in 50.0% (90/179) of peritumoral infiltrating lymphocytes. HLA-F expression in gastric adenocarcinoma was significantly correlated with the depth of invasion, nodal involvement, and lymphatic and venous invasions (P < 0.01, all). HLA-F positivity of infiltrating cells near the tumor showed no correlation with clinicopathological features. HLA-F-positive patients had a significantly worse prognosis than HLA-F-negative patients (P = 0.012). However, HLA-F expression was not an independent prognostic factor in multivariate analysis. CONCLUSIONS: The present study provides the first evidence that neo-HLA-F expression is of clinical significance in gastric adenocarcinoma. HLA-F expression in gastric adenocarcinoma may promote the aggressive behavior of tumors by suppressing the activity of antitumor immune effector cells.

Cancerous HLA class I expression and regulatory T cell infiltration in gastric cancer.

BACKGROUND: Since antitumor immune reactions between tumors and intratumoral immunocytes have been verified in several human tumors, immunological therapeutic strategies must be considered to obtain the proper efficacy of tumor shrinkage under these conditions. Human leukocyte antigen (HLA) class I expression in cancer cells and degree of infiltration of regulatory T cells (Tregs) in the stroma have been regarded as important markers of antitumor immune reactions in the context of independent immunological mechanisms. In the current study, we investigated HLA class I expression and Treg cells infiltration in gastric cancer and discussed the clinical implications of this combinatory analysis in gastric cancer. PATIENTS AND METHODS: A total of 141 gastric cancer patients who received R0 gastrectomy at Kagoshima University Hospital were studied. Immunohistochemically, in 141 gastric cancer patients, HLA class I expression and Treg cell infiltration in cancerous tissue were evaluated using HLA class I (EMR8-5) and forkhead box p3 (FOXP3) monoclonal antibodies. The correlation between clinical factors and tumor-infiltrating Treg cells was analyzed. RESULTS: HLA class I expression was positively associated with depth of tumor invasion (P < 0.05). Infiltration of Foxp3-positive cells did not correlate with any clinicopathological markers. HLA class I expression had no association with Treg cell infiltration (r = 0.04). A better postoperative outcome was associated with fewer numbers of Treg infiltration (P = 0.034). A combination of HLA and Treg analysis may lead to a more accurate prediction of postoperative outcome (P = 0.02). CONCLUSIONS: Two different antitumor immunological markers, Treg infiltration and HLA class I expression, affected clinicopathological factors in gastric cancer by different mechanisms. Thus, an immunological combination of HLA class I expression and Treg cell infiltration may more accurately predict postoperative outcome. Immunological balance needs to be restored after evaluation of each immunological deficit in gastric cancer.

Prognostic impact of CD168 expression in gastric cancer.

BACKGROUND: Interactions of stromal hyaluronic acid (HA) with its binding protein RHAMM (receptor for HA-mediated motility) (CD168) have been reported to affect tumor extension and the migration of crucial molecules to promote tumor progression and metastases. Cancerous CD168 expression is correlated with aggressive biological features in several cancers. However, the clinical implications of CD168 positivity in gastric cancer have remained unclear. METHODS: We examined the CD168 expression of 196 consecutive gastric cancer patients by immunohistochemistry. According to CD168 positivity, the 196 gastric cancer patients were divided into two groups (57 CD168-positive and 139 CD168-negative patients). The correlation between CD168 expression and clinicopathological factors (age, sex, histology, tumor depth, lymph node status, and vessel invasion) was evaluated according to the Japanese Classification of Gastric Carcinoma. RESULTS: Cancerous CD168 expression was detectable in 57 of the 196 tumors (29%). CD168 positivity was significantly correlated with the depth of invasion, nodal involvement, and vessel invasion (p < 0.01). Survival analysis of the 196 gastric cancer patients showed that the CD168-positive group had a significantly higher mortality than the CD168-negative group (p < 0.01). In terms of a correlation with CD168 positivity at separate clinical stages, a significance difference was only found in stages II and III. Multivariate analysis revealed that CD168 expression was a significant independent prognostic marker (p = 0.013) after depth of invasion (p < 0.005) and nodal involvement (p < 0.01). CONCLUSION: Our results suggest that cancerous CD168 positivity is strongly related to the invasion and metastasis of gastric cancer tumors. These results suggest that cancerous CD168 expression can be used as a prognostic marker of gastric cancer owing to its interactions with stromal hyaluronic acid.

Clinical implication of CD166 expression in gastric cancer.

BACKGROUND: CD166 is one of the cell-surface immunoglobulins, and is well known to regulate leukocyte mobility. Its expression is associated with aggressive tumor behavior. CD166 expression is a prognostic marker in several cancers, but the predictive value of CD166 expression in gastric cancer has not been clarified yet. PATIENTS AND METHODS: A total of 142 gastric cancer patients who consecutively received curative gastrectomy in Kagoshima University Hospital were enrolled in the current study. The patients were composed of 99 men and 43 women, ranging in age from 42 to 84 years (mean 63 years). Cancerous CD166 expression was evaluated immunohistochemically. RESULTS: Cancerous CD166 expression was identified in not only cellular membrane but also cytoplasm. The rates of membranous and cytoplasmic CD166 positivities were 25.4% and 34.4%, respectively. Cytoplasmic and membranous CD166 positivities were significantly correlated with nodal involvement and vascular invasion. Survival analysis of the 142 gastric cancer patients revealed that membranous CD166-positive group (median survival 18.6 months, range 0.3-104.5 months) had a significantly poorer outcome than CD166-negative group (median 25.7 months range 1.4-106 months) (P < 0.05). CONCLUSIONS: Membranous CD166-positivity may contribute to one of the promising prognostic markers in gastric cancer.

Expression of Maternal Embryonic Leucine Zipper Kinase (MELK) Correlates to Malignant Potentials in Hepatocellular Carcinoma.

BACKGROUND/AIM: Maternal embryonic leucine zipper kinase (MELK) is categorized as a member of AMP-activated protein kinase families. Various MELK-associated cellular and biological processes affect multiple stages of tumorigenesis. The aim of the present study was to clarify the relationship between MELK expression and hepatocellular carcinoma (HCC) clinicopathological features. MATERIALS AND METHODS: In thirty conserved frozen primary HCC and non-HCC samples MELK mRNA expression was examined by quantitative real-time polymerase chain reaction (PCR). RESULTS: HCC tissues exhibited significantly higher expression levels compared to non-cancerous tissues. MELK expression had a statistically parallel correlation between tumor diameter and protein induced by vitamin K absence or antagonist II (PIVKA-II). The overall survival (OS) and recurrence-free survival (RFS) of the low MELK mRNA expression group was significantly longer than that of the high MELK mRNA expression group. CONCLUSION: MELK expression in HCC is extremely intense compared to its expression reported in other types of cancer. MELK could be a promising effective tumor marker of HCC and further consideration is needed.

Clinical and biological impact of cyclin-dependent kinase subunit 2 in esophageal squamous cell carcinoma.

Cyclin-dependent kinase subunit 2 (CKS2) is a cyclin-dependent kinase subunit (CKS) family member that participates in cell cycle regulation. Few studies have investigated its involvement in esophageal squamous cell carcinoma (ESCC). The aim of the present study was to assess the clinical significance of CKS2 in ESCC. We used immunohistochemistry to study the clinicopathologic significance of CKS2 protein expression in 121 patients with ESCC. Using real-time reverse transcriptase-polymerase chain reaction (RT-PCR), we examined the expression of CKS2 mRNA in tumors and the corresponding normal esophageal tissues that were obtained from 62 patients. Finally, siRNA-mediated attenuation of CKS2 expression was examined in vitro. CKS2 protein expression was significantly correlated with depth of tumor invasion, clinical stage, lymphatic invasion and distant metastasis (p=0.033, 0.028, 0.041 and 0.009, respectively). CKS2 mRNA expression was higher in cancer tissue than in corresponding normal tissue (p<0.001). Patients with positive-CKS2 protein expression had a poorer five year survival frequency than patients who did not express CKS2 protein (p=0.025). In vitro, siRNA-mediated suppression of CKS2 slowed the growth rate of ESCC cells compared to control cells (p<0.001). The evaluation of CKS2 expression is useful for predicting the cause of malignant tumors and the prognosis of patients with ESSC.

Clinical implications of DLL4 expression in gastric cancer.

BACKGROUND: Delta-like ligand 4 (DLL4)-Notch signaling plays a key role in tumor neovascular development and angiogenesis during tumor growth. The clinical significance of DLL4 expression in gastric cancer has not been clarified. METHODS: Gastric cancer cell lines and 180 gastric cancer patients were enrolled. DLL4 expression in gastric cancer cells and stroma was identified and evaluated immunohistochemically. The association between DLL4 and clinicopathological factors was also assessed. RESULTS: DLL4 expression was identified in the cellular membrane and cytoplasm of gastric cancer cells by immunoblotting and immunohistochemical staining. DLL4 positivity in cancer cells and stroma was found in 88 (48%) and 41 (22%) of the 180 gastric cancer patients respectively. Both cancer and stromal DLL4 expression significantly correlated with more advanced tumor depth, nodal involvement, and lymphatic and venous invasion. A strongly positive association between cancerous and stromal DLL4 expression was identified (p < 0.01). Both cancerous and stromal DLL4 expression were prognostic markers in gastric cancer as determined by univariate analysis. CONCLUSIONS: Cancerous and stromal DLL4 expression was found in 48% and 22% in gastric cancer, and significantly affected postoperative clinical outcomes. Cancerous and stromal DLL4 expression may be an effective target of anti-DLL4 treatment in gastric cancer.