Introduction of cytogenetic tests in colorectal cancer screening.

BACKGROUND AND AIM. The existing tests practiced on a large scale in colorectal cancer (CRC) screening do not fully accomplish the goal of best specificity and sensitivity or either an optimal cost/efficiency ratio. We aimed to analyze genetic mutations diagnosed in the DNA of exfoliated cells in the stool of the patients diagnosed with CRC through screening. We also aimed to demonstrate the similarity between the detected mutations in tumor samples and in exfoliated cells in the stool in order to prove the reliability of these cytogenetic tests, so that they could be introduced in CRC screening program. METHODS. We studied 200 patients diagnosed with CRC from whom we prelevated biopsy and stool samples. Samples were submitted to genetic analysis through denaturing gradient polyacrylamide gel electrophoresis method, and through polyacrylamide gel electrophoresis method for the heteroduplex analysis. Analyzed genes were APC, COL11A1, MLH1, MSH2 and MSH6. The chromosomal study was carried out using the PRINS technique. RESULTS. We discovered mutations in the APC gene (exons 4, 9, 13, and 15c) and COL11A1 gene (exon 54). Our chromosomal study detected instability of chromosomes 1, 7, 9, 20, and in 10 achrocentric chromosomes. CONCLUSIONS. Our results plead for the implementation of proposed cytogenetic tests in CRC screening programs.

Efficacy and safety of peginterferon alpha-2a (40KD) in HBeAg-positive chronic hepatitis B patients.

AIM: The study was designed to evaluate the efficacy and safety of peginterferon alpha-2a in HBeAg-positive chronic hepatitis B patients, nonresponders or relapsers after previous lamivudine or standard interferon therapy. METHODS: This prospective, national, multicentric, open label, not randomized trial enrolled 43 HBeAg-positive chronic hepatitis B patients with detectable HBsAg for at least 6 months prior to screening, positive HBeAg and negative anti-HBe, serum HBV DNA levels of at least 500,000 copies/mL by PCR assay, elevated ALT up to 10 x ULN, no response or relapse after previous lamivudine or standard interferon therapy. All eligible patients received pegIFN alpha-2a 180 micrograms weekly for 48 weeks with 24 weeks treatment free follow-up. There were two main efficacy assessments: HBeAg seroconversion and viral supression below 100,000 copies/mL. RESULTS: HBeAg seroconversion rate at the end-of-treatment was 4.65% (n=2; p less than 0.05) increasing to 11.62% 24 weeks after end of therapy (n=5; p less than 0.05). The rate of viral supression at levels below 100,000 copies/mL was 23.25% (n=10; p less than 0.05) at end-of-treatment, and 16.3% (n=7; p less than 0.05) at end of follow-up. ALT normalization was obtained in 20.9% (p less than 0.05) of patients at end-of-treatment, the percentage being significantly higher - 37.2% (p less than 0.05) at the end of follow-up. CONCLUSIONS: Even in a difficult-to-treat patient population with HBeAg-positive chronic hepatitis B, peginterferon alpha 2a proved to be efficient in a defined proportion of patients. The increase in HBeAg seroconversion rate from end-of-treatment (4.65%) to the end of follow-up period (11.62%) also proves the benefits of prolonged immunological effect of pegIFN alpha 2a.

Noninvasive detection through REMS-PCR technique of K-ras mutations in stool DNA of patients with colorectal cancer.

BACKGROUND AND AIMS: Tumor exfoliated cells that shed into stool are attractive targets for molecular screening and early detection of colon malignancies. Many studies have suggested that the detection of activated ras may have diagnostic or prognostic importance. The aim of this study was to establish the suitability for use in diagnostic laboratories of the noninvasive screening test of K-ras mutation determination in the stool and its routine prognostic value in colorectal cancer. METHODS: Paired stool and tissue specimens obtained after polypectomy and colorectal biopsy from 28 patients diagnosed solely by histopathological findings with primary colorectal carcinoma, were prospectively studied for K-ras codon 12 mutations by restriction endonuclease-mediated selective (REMS)-PCR. RESULTS: DNA was obtained in 28 of tissue samples (100%) and 26 of stool samples (92.8%). K-ras codon 12 mutation was seen in 14 (50.0%) paired stool and tissue samples. Mutation detection was possible in 1000-fold excess of wild-type sequence. These results may be important in the design of genetic screening programs, determination of prognosis, early detection and treatment for patients with colon malignancy. CONCLUSIONS: The sensitivity and specificity of K-ras determination on stool-derived DNA in patients with colorectal carcinoma, support the opportunity of a large-scale trial to validate its use as a screening test. REMS- PCR is not labor intensive, but a sensitive, rapid, and robust assay for the detection of point mutations, and was introduced by us in a routine diagnostic laboratory.

The feasibility of FOBT tests in colorectal cancer screening in Dobrogea.

BACKGROUND AND AIM: The high incidence of colorectal cancer in Eastern Europe and the declining mortality due to this pathology in the Western World, where screening programs for cancer are available, prove the necessity of implementing colorectal cancer screening in Romania, too. The aim of our study was to detect colorectal cancer in asymptomatic stages, where surgical treatment could be curative. METHOD: The study was conducted in the Gastroenterology Department of Emergency Hospital, Constanta County, over a period of 18 months. We recruited apparently healthy people following all criteria recommended by the guidelines. RESULTS: From the total of 1098 patients included in the study, 162 patients with FOBT test positive followed the screening program undergoing colonoscopy or barium enema investigation. The rate of acceptance regarding the screening procedures was 70.3%. Advanced colon lesions were found in 14 patients (1.27%) and cancers in 7 cases (0.63%). According to TNM classification 5 cancers (71.4%) were surgically curative (TNM I/II/III) and 2 (28.5%) were advanced (TNM IV). The positive predictive value (PPVs) of FOBT for cancer was 4.7%. CONCLUSION: Even if the effect of screening on mortality was not demonstrated, our study results confirm the necessity of colorectal cancer screening in our country, as it is worldwide, detecting cancers in curative stages. The detection rate of FOBT positive tests for neoplasia was similar to other studies.