Immunohistochemical examination of anti-STn monoclonal antibodies LLU9B4, B72.3, and B35.2 for their potential use as tumor markers.

PURPOSE: Several investigators, including ourselves, have demonstrated by immunohistochemistry that in malignancy of colon, the tumor cells or cells adjacent to the tumor become reactive with anti-STn monoclonal antibodies, while in normal individuals the colonic cells do not react with anti-STn monoclonal antibodies. In the present study, an anti-STn monoclonal antibody LLU9B4 was generated in the laboratory by immunization of mice with STn extracted from LS174T, along with commercially available B72.3 and B35.5 anti-STn monoclonal antibodies for their sensitivity in staining colon cancer sections. RESULT: The results showed that 83.3% stained positive with 9B4 and 66.6% with B72.3, and there was no staining with B35.5 monoclonal antibody. The positive staining was mainly in the cells adjacent to colon cancer. It was also observed that the staining with LLU9B4 was much more pronounced than with B72.3. CONCLUSION: Our study indicates that these antibodies may at least be more sensitive and specific for colon cancers than the current standard of care, FOBT.

Clinical implications of hepatic steatosis in patients with chronic hepatitis C: a multicenter study of U.S. veterans.

Studies have indicated a high prevalence of hepatic steatosis in patients with chronic hepatitis C (CHC). To address the impact of steatosis on the clinical course of CHC and treatment response requires large multicenter studies. The present study analyzed hepatitis C virus (HCV)-infected veterans enrolled in a U.S. Veteran Administration multicenter study of the epidemiology and response to interferon alpha-2b and ribavirin treatment. Of the 357 patients, 97.1% were males, with a mean age of 48.7+/-6.4 years, and 184 (51.5%) had hepatic steatosis. The mean body mass index (BMI) was 29.3+/-5.2 kg/m(2), including 37.1% who were obese (BMI, > or =30 kg/m(2)). Stage III-IV fibrosis was present in 111 of 334 (33.3%) of the patients. After adjusting for age, race, and history of alcohol use in the past 12 months, only stage III-IV fibrosis was independently and significantly associated with hepatic steatosis (P=0.03). There was a trend of association between obesity and steatosis independent of the other factors. Only HCV genotype was independently associated with a sustained virological response (SVR) to interferon alpha-2b and ribavirin treatment after adjusting for age, alcohol use, steatosis, BMI, stage III-IV fibrosis, serum AFP, and HCV load. In conclusion, analyses of our multicenter trial data demonstrated that the prevalence of hepatic steatosis is 51.5% in HCV-infected U.S. veterans. We found that steatosis is independently associated with stage III-IV fibrosis. However, only HCV genotype, and not steatosis, obesity, or stage III-IV fibrosis, was associated with SVR to interferon alpha-2b and ribavirin treatment.

Inhibited proliferation of cyclooxygenase-2 expressing human hepatoma cells by NS-398, a selective COX-2 inhibitor.

Hepatocellular carcinoma (HCC) is a growing human health problem worldwide. Limited treatment and poor prognosis of this disease emphasize the importance in developing an effective chemoprevention. Overexpression of cyclooxygenase-2 (COX-2) has been associated with hepatocarcinogenesis. Although COX-2 inhibitors have been tested for chemoprevention of colon cancer, it remains unknown whether these agents possess anti-HCC effects as well. The present study assessed the effects of a selective COX-2 inhibitor, NS-398, on proliferation of human hepatoma cells in association with COX-2 expression, and the possible mechanisms. In four tested human hepatoma cell lines, overexpression of COX-2 was confirmed in HepG2, HuH7, and Chang liver cells, but not in PLC/PRF/5 cells. Addition of 50 micro M NS-398 resulted in both dose-dependent and time-course inhibition of HepG2 proliferation. In contrast, addition of 50 micro M NS-398 to COX-2 non-expressing PLC/PRF/5 cells resulted in only a mild reduction of cell proliferation. Consistent with this, a 48-h culture of HepG2 cells with 50 micro M NS-398 caused a significant decrease of prostaglandin E2 (PGE2) production. While, the same NS-398 treatment showed only a mild suppression of PGE2 production in COX-2 non-expressing PLC/PRF/5 cells. These findings indicate that NS-398-induced suppression of HepG2 proliferation appears mediated by decreased COX-2/prostaglandin (PG) production. We also found that NS-398-induced inhibition of HepG2 proliferation was associated with decreased 5-bromo-2'-deoxyuridine (BrdU) uptake, suggesting a reduced cell cycle progression in G1-S transition. NS-398 treatment also enhanced the apoptotic rate in COX-2 expressing HepG2 cells, but not in COX-2 non-expressing PLC/PRF/5 cells. Our findings confirmed an effective inhibitory effect of NS-398 on proliferation of COX-2 expressing human hepatoma cells through a decreased COX-2/PG activity that is associated with altered cell cycle progression and apoptotic rate.

Noninvasive colorectal cancer screening.

Abnormal mucin with the STn epitope is produced by colorectal cancer cells and is immunologically distinguishable from normal colonic mucin. Herein we describe a technique of detecting abnormal mucin in fecal samples as a method of screening for colorectal neoplasia. Soluble glycoproteins from fecal samples of patients with symptoms of bowel disease and asymptomatic volunteer subjects were isolated by centrifugation and ethanol precipitation. The protein content of the soluble fraction was normalized and tested by immunoassay (slot dot). Anti-COTA monoclonal antibody SP-21, which reacts with STn epitope, was applied in the reaction, and the optical density of each slot dot was determined by imaging densitometer. Quantitative values of samples were determined from the standard curve obtained with highly purified COTA. COTA values > 15 microg/ml were considered positive for neoplasia. Results indicated that 5/6 colon cancers, 6/22 adenomas, 1/8 colitis cases, and 2/58 normal patients were positive in the test. The pilot study revealed that COTA assay is sensitive and more specific than Hemoccult screening for colorectal neoplasia.