Asian Science Citation Index is committed to provide an authoritative, trusted and significant information by the coverage of the most important and influential journals to meet the needs of the global scientific community.  
ASCI Database
308-Lasani Town,
Sargodha Road,
Faisalabad, Pakistan
Fax: +92-41-8815544
Contact Via Web
Suggest a Journal
 
Articles by M Omata
Total Records ( 2 ) for M Omata
  N Yamamichi , R Shimomura , K. i Inada , K Sakurai , T Haraguchi , Y Ozaki , S Fujita , T Mizutani , C Furukawa , M Fujishiro , M Ichinose , K Shiogama , Y Tsutsumi , M Omata and H. Iba
 

Purpose: To better understand microRNA miR-21 function in carcinogenesis, we analyzed miR-21 expression patterns in different stages of colorectal cancer development using in situ hybridization (ISH).

Experimental Design: Locked nucleic acid (LNA)/DNA probes and a biotin-free tyramide signal amplification system were used in ISH analyses of miRNA expression. Conditions for specific detection of miR-21 were determined using human cell lines and miR-21–expressing lentiviral vectors. Expression was determined in 39 surgically excised colorectal tumors and 34 endoscopically resected colorectal polyps.

Results: In the surgical samples, miR-21 expression was much higher in colorectal cancers than in normal mucosa. Strong miR-21 expression was also observed in cancer-associated stromal fibroblasts, suggesting miR-21 induction by cancer-secreted cytokines. Protein expression of PDCD4, a miR-21 target, was inversely correlated with miR-21 expression, confirming that miR-21 is indeed a negative regulator of PDCD4 in vivo. In the endoscopic samples, miR-21 expression was very high in malignant adenocarcinomas but was not elevated in nontumorigenic polyps. Precancerous adenomas also frequently showed miR-21 up-regulation.

Conclusion: Using the LNA-ISH system for miRNA detection, miR-21 was detectable in precancerous adenomas. The frequency and extent of miR-21 expression increased during the transition from precancerous colorectal adenoma to advanced carcinoma. Expression patterns of miR-21 RNA and its target, tumor suppressor protein PDCD4, were mutually exclusive. This pattern may have clinical application as a biomarker for colorectal cancer development and might be emphasized by self-reinforcing regulatory systems integrated with the miR-21 gene, which has been previously shown in cell culture.

  Y Nakai , H Isayama , T Sasaki , N Sasahira , H Kogure , K Hirano , T Tsujino , H Ijichi , K Tateishi , M Tada , M Omata and K. Koike
  Objective

We investigated the impact of S-1 on the prognosis of patients with gemcitabine-refractory pancreatic cancer.

Methods

A total of 108 patients with gemcitabine-refractory pancreatic cancer were divided by the time of S-1 introduction in our institution: 47 patients who experienced progressive disease before February 2005 (pre-S-1 group) and 61 patients showed progressive disease after February 2005 (post-S-1 group). Introduction rates of second-line chemotherapy and survival were compared. Prognostic factors for residual survival were analyzed using the Cox proportional hazards model.

Results

Introduction rates of second-line chemotherapy were 12.8% in the pre-S-1 group and 45.9% in the post-S-1 group. Second-line chemotherapy was administered to 34 patients: 29 using S-1, 4 using 5-fluorouracil-based chemoradiation and 1 using 5-fluorouracil. The objective response rate, progression-free survival and overall survival for second-line chemotherapy with S-1 were17.2%, 2.5 and 7.7 months, respectively. By the introduction of S-1 in our institution, residual survival was prolonged from 3.1 months in the pre-S-1 group to 6.7 months in the post-S-1 group (P < 0.001). Overall survival from the initiation of gemcitabine was 8.8 months in the pre-S-1 group and 11.3 months in the post-S-1 group (P = 0.013). Multivariate analysis identified the post-S-1 group (hazard ratio, 0.43; P = 0.001), gender, performance status, liver metastasis, and lactate dehydrogenase and C-reactive protein levels at progressive disease for gemcitabine to be prognostic factors for residual survival.

Conclusions

The introduction of S-1 might improve the prognosis of patients with gemcitabine-refractory pancreatic cancer.

 
 
 
Copyright   |   Desclaimer   |    Privacy Policy   |   Browsers   |   Accessibility