Hoguen Kim

MicroRNA Expression Profiles in Serous Ovarian Carcinoma

Purpose: Although microRNAs have recently been recognized as riboregulators of gene expression, little is known about microRNA expression profiles in serous ovarian carcinoma. We assessed the expression of microRNA and the association between microRNA expression and the prognosis of serous ovarian carcinoma. Experimental Design: Twenty patients diagnosed with serous ovarian carcinoma and eight patients treated for benign uterine disease between December 2000 and September 2003 were enrolled in this study. The microRNA expression profiles were examined using DNA microarray and Northern blot analyses. Results: Several microRNAs were differentially expressed in serous ovarian carcinoma compared with normal ovarian tissues, including miR-21, miR-125a, miR-125b, miR-100, miR-145, miR-16, and miR-99a, which were each differentially expressed in >16 patients. In addition, the expression levels of some microRNAs were correlated with the survival in patients with serous ovarian carcinoma. Higher expression of miR-200, miR-141, miR-18a, miR-93, and miR-429, and lower expression of let-7b, and miR-199a were significantly correlated with a poor prognosis (P < 0.05). Conclusion: Our results indicate that dysregulation of microRNAs is involved in ovarian carcinogenesis and associated with the prognosis of serous ovarian carcinoma.

The Chromosome-Centric Human Proteome Project for cataloging proteins encoded in the genome

The Chromosome-Centric Human Proteome Project for cataloging proteins encoded in the genome

Phase II Study of Erlotinib in Advanced Non–Small-Cell Lung Cancer After Failure of Gefitinib

PURPOSE This study was designed to evaluate the efficacy and toxicity of erlotinib in patients with advanced non-small-cell lung cancer (NSCLC) who experienced disease progression after treatment with gefitinib. PATIENTS AND METHODS The study included stage IIIB/IV recurrent or metastatic NSCLC patients who received two or three prior chemotherapy regimens and showed progressive disease within 4 months of gefitinib therapy discontinuation. Patients received erlotinib 150 mg/d until disease progression or unacceptable toxicity. Epidermal growth factor receptor (EGFR) mutations and other genetic abnormalities were analyzed from available tumor samples. RESULTS Patient and disease characteristics (N = 21) included median age 56 years; number of prior chemotherapy regimens (three; n = 11); female sex (n = 11); adenocarcinoma (n = 15); and never-smoker status (n = 11). Among the 17 patients with tumor samples available, EGFR mutations were detected in five. The disease control rate (DCR) and response rate (RR) for all patients were 28.6% and 9.5%, respectively. The median duration of disease control was 125 days. The median time to progression and overall survival were 60 days and 158 days, respectively. Patients who had stable disease (SD) while receiving gefitinib showed significantly higher DCR (75% v 17.6% in non-SD patients; P = .050) and RR (50.0% v 0% in non-SD patients; P = .029). Among 17 patients with biomarker results available, those lacking EGFR mutations who had SD while receiving gefitinib showed significantly higher DCR and RR. CONCLUSION Erlotinib seems to be a potential therapeutic option for the treatment of advanced NSCLC patients with wild-type EGFR who had SD while receiving gefitinib.

Allelotype analysis of hepatocellular carcinoma

To elucidate the genetic events which may play important roles in hepatocarcinogenesis, we examined every non‐acrocentric chromosome arm of 22 hepatocellular carcinomas (HCCs) for loss of heterozygosity (LOH) using 68 highly polymorphic microsatellite markers. Thirty‐six (92%) of 39 chromosome arms showed LOH in at least one patient, however 3 chromosome arms, 2p, 2q, and 20q, did not show any LOH. High to moderate frequency of LOH (>30% of informative cases) was observed at chromosomes 1q (68.1%), 4q (72.7%), 8p (63.6%), 8q (77.3%), 10q (33.3%), 13q (40%), 14q (46.1%), 16q (59.1%), and 17p (46.2%). Among these, LOH on chromosomes 1q and 8q have not been previously identified in HCC. Our results suggest that novel tumor suppressor genes may be involved in the development and progression of HCC. Int. J. Cancer 75:29–33, 1998.© 1998 Wiley‐Liss, Inc.

Gene expression signature-based prognostic risk score in gastric cancer

Purpose: Despite continual efforts to develop a prognostic model of gastric cancer by using clinical and pathologic parameters, a clinical test that can discriminate patients with good outcomes from those with poor outcomes after gastric cancer surgery has not been established. We aim to develop practical biomarker-based risk score that can predict relapse of gastric cancer after surgical treatment. Experimental Design: Microarray technologies were used to generate and analyze gene expression profiling data from 65 gastric cancer patients to identify biomarker genes associated with relapse. The association of expression patterns of identified genes with relapse and overall survival was validated in independent gastric cancer patients. Results: We uncovered two subgroups of gastric cancer that were strongly associated with the prognosis. For the easy translation of our findings into practice, we developed a scoring system based on the expression of six genes that predicted the likelihood of relapse after curative resection. In multivariate analysis, the risk score was an independent predictor of relapse in a cohort of 96 patients. We were able to validate the robustness of the six-gene signature in an additional independent cohort. Conclusions: The risk score derived from the six-gene set successfully prognosticated the relapse of gastric cancer patients after gastrectomy. Clin Cancer Res; 17(7); 1850–7. ©2011 AACR.

Solid pseudopapillary tumor of the pancreas suggesting malignant potential

Objectives: It has been suggested that the histopathologic features associated with malignant potential in solid pseudopapillary tumors (SPTs) of the pancreas include cellular polymorphism, mitotic activity, peripancreatic tissue invasion, neural invasion, lymphovascular invasion, and lymph node metastasis. This study aimed to delineate the features predicting SPTs with malignant potential, which can be easily assessed in the clinical setting, and long-term results of patients who underwent resection of SPT. Methods: A retrospective review and analysis were done of 33 patients who had SPTs that were surgically treated. Results: Eleven patients (33.3%) had SPTs suggesting malignant potential among surgically treated patients with SPTs. The local invasion to the peripancreatic tissue was the most frequent malignant pathological feature (7/11 patients, 63.7%). Using univariate analysis, tumor size greater than 5 cm was a significant clinical factor to predict SPTs with malignant potential (P = 0.022). The prognosis was excellent. No statistically significant survival difference was noted between groups of malignant potential and benign pathology (P = 0.1904). Conclusions: Malignant SPTs are low-grade tumors with good prognosis. Adequate surgical intervention is necessary. Especially, SPTs over 5 cm in diameter need to be treated carefully because of the chance of malignant pathology. Careful long-term follow-up is necessary in those patients in case of possible tumor recurrences.

Oncologic outcomes after neoadjuvant chemoradiation followed by curative resection with tumor-specific mesorectal excision for fixed locally advanced rectal cancer: Impact of postirradiated pathologic downstaging on local recurrence and survival

Objective:The purpose of this study was to determine the oncologic outcomes and clinical factors affecting survival in patients who underwent neoadjuvant chemoradiotherapy following tumor specific mesorectal excision for locally advanced, fixed rectal cancer. Summary Background Data:Neoadjuvant chemoradiation therapy has resulted in significant tumor downstaging, which enhances curative resection and subsequently improves local disease control for rectal cancer. However, oncologic outcomes, according to clinical factors, have not yet been fully understood in locally advanced and fixed rectal cancer. Methods:A total of 114 patients who had undergone neoadjuvant chemoradiation for advanced rectal cancer (T3 or T4 and node positive) were investigated retrospectively. Chemotherapy was administered intravenously with 5-FU and leucovorin during weeks 1 and 5 of radiotherapy. The total radiation dose was 5040 cGY in 25 fractions delivered over 5 weeks. Tumor-specific mesorectal excision was done 4 to 6 weeks after the completion of neoadjuvant chemoradiation. Survival and recurrence rates, according to the pathologic stage, were evaluated. Moreover, factors affecting survival were investigated. Results:The 5-year survival rates according to pathologic stage were: 100% in pathologic complete remission (n = 10), 80% in stage I (n = 23), 56.8% in stage II (n = 34), and 42.3% in stage III (n = 47) (P = 0.0000). Local, systemic, and combined recurrence rates were 11.4%, 22.8%, and 3.5%, respectively. Multivariate analysis showed that the pathologic N stage and operation method were the independent factors affecting survival rate. Conclusion:Pathologic complete remission showed excellent oncologic outcomes, and the pathologic N stage was the most important factor for oncologic outcomes.

Identification of S100A8 and S100A9 as serological markers for colorectal cancer.

In search of novel serological protein biomarkers for human colorectal cancer (CRC), we analyzed CRC tissues using two-dimensional difference in-gel electrophoresis (2D-DIGE) on a narrow range IPG strip (pH 5.5-6.7). By comparing tumor tissues with matched normal tissues in a pairwise manner (n = 6), we identified 34 up-regulated and 17 down-regulated spots with intensity changes greater than 2-fold (Students t-test, p < 0.05). Expression of both mRNA and protein levels of four proteins, adenosylhomocysteinase, Nm23-H1, S100A8 and S100A9, in CRC tissues was further evaluated by semiquantitative RT-PCR and Western blot analysis. The results revealed that all four proteins were elevated in the tumor tissues. We also confirmed, by immunohistochemistry, that adenosylhomocysteinase and Nm23-H1 were overexpressed in tumor cell cytoplasm and that S100A8 and S100A9 proteins were strongly expressed in tumor infiltrating immune cells. Western blot analysis with fractionated plasma samples showed that S100A8 and S100A9 were significantly increased in the plasma of CRC patients (n = 77) and colorectal adenoma patients (n = 11), compared to healthy controls (n = 21). The area under a receiver operating characteristic (ROC) curve was 0.91 for S100A8 and 0.89 for S100A9, which was superior to the established tumor marker carcinoembryonic antigen with 0.78 for the area under the ROC curve. Some patients with inflammatory diseases such as pancreatitis also showed elevated levels of the proteins. Importantly, in comparison to the control group, both proteins showed a remarkable change at the early stage of cancer. Therefore, we suggest S100A8 and S100A9 as candidates for serological biomarkers in combination with other serum markers that aid CRC diagnosis.

Enhanced Antitumor Effect of Oncolytic Adenovirus Expressing Interleukin-12 and B7-1 in an Immunocompetent Murine Model

Purpose: We investigated whether an armed viral platform, where lytic property of a viral infection is coupled to viral-mediated delivery of therapeutic genes, could increase the therapeutic potential of a viral-based therapy. Experimental Design: We generated interleukin (IL)-12-expressing oncolytic adenovirus (YKL-IL-12) and IL-12- and B7-1-expressing (YKL-IL12/B7) oncolytic adenovirus. Therapeutic efficacy of these newly engineered adenoviruses was then evaluated in vivo using an immunocompetent mouse bearing murine melanoma B16-F10 tumors. Overall survival was assessed with the Kaplan-Meier method. The induction of immune cell cytotoxicity was assessed by CTL assay, IFN-γ enzyme-linked immunospot assay, and immunohistochemical studies. Results: YKL-IL12/B7 oncolytic adenovirus, expressing both IL-12 and B7-1, showed a higher incidence of complete tumor regression compared with the analogous oncolytic adenovirus, YKL-1, or IL-12-expressing, YKL-IL12. Significant survival advantage was also seen in response to YKL-IL12/B7. Moreover, IL-12 and IFN-γ levels produced in tumors treated with YKL-IL12/B7 was significantly greater than those treated with YKL-IL12. The enhanced survival advantage was mediated by the induction of immune cell cytotoxicity. In agreement with these results, massive infiltration of CD4+ and CD8+ T cells into tissues surrounding the necrotic area of the tumor was observed following in situ delivery of YKL-IL12/B7. Conclusion: Combination of oncolysis and the enhancement of antitumor immune response by oncolytic adenovirus expressing both IL-12 and B7-1 elicits potent antitumor effect and survival advantage.

Frequent inactivation of SPARC by promoter hypermethylation in colon cancers

Epigenetic modification of gene expression plays an important role in the development of human cancers. The inactivation of SPARC through CpG island methylation was studied in colon cancers using oligonucleotide microarray analysis and methylation specific PCR (MSP). Gene expression of 7 colon cancer cell lines was evaluated before and after treatment with the demethylating agent 5‐aza‐2′‐deoxycytidine (5Aza‐dC) by oligonucleotide microarray analysis. Expression of SPARC was further examined in colon cancer cell lines and primary colorectal cancers, and the methylation status of the SPARC promoter was determined by MSP. SPARC expression was undetectable in 5 of 7 (71%) colorectal cancer cell lines. Induction of SPARC was demonstrated after treatment with the demethylating agent 5Aza‐dC in 5 of the 7 cell lines. We examined the methylation status of the CpG island of SPARC in 7 colon cancer cell lines and in 20 test set of colon cancer tissues. MSP demonstrated hypermethylation of the CpG island of SPARC in 6 of 7 cell lines and in all 20 primary colon cancers, when compared with only 3 of 20 normal colon mucosa. Immunohistochemical analysis showed that SPARC expression was downregulated or absent in 17 of 20 colon cancers. A survival analysis of 292 validation set of colorectal carcinoma patients revealed a poorer prognosis for patients lacking SPARC expression than for patients with normal SPARC expression (56.79% vs. 75.83% 5‐year survival rate, p = 0.0014). The results indicate that epigenetic gene silencing of SPARC is frequent in colon cancers, and that inactivation of SPARC is related to rapid progression of colon cancers.