MedicineWorld.Org
Your gateway to the world of medicine
Home
News
Cancer News
About Us
Cancer
Health Professionals
Patients and public
Contact Us
Disclaimer

Medicineworld.org: 5-fluorouracil in colonic neoplasm?

Back to colon cancer blog Blogs list Cancer blog  


Subscribe To Colon Cancer Blog RSS Feed  RSS content feed What is RSS feed?

5-fluorouracil in colonic neoplasm?




5-fluorouracil (5-FU) is a common chemotherapeutical drug. It exerts its antitumor effect through competitive thymidylate synthase (TS) inhibition. Thymidylate synthase (TS) catalyses deoxyuridine-5-monophosphate (dUMP) to 2-deoxythymydine-5-monophosphate (dTMP). It is the only de novo source of thymidylate, an essential precursor of DNA biosynthesis. In the 5-untranslated region of TS gene, there a unique tandem repeated sequence. There are three predominant genotypes of TS: (1) Homozygous with two tandem repeats (2R/2R); (2) homozygous with three tandem repeats (3R/3R); (3) heterozygous with both alleles (2R/3R). It was reported that TS genes with the triple repeats have higher expression activity than those with double repeats in vitro and in vivo.



5-fluorouracil in colonic neoplasm?

The critical role of TS in nucleotide metabolism has made it an important target for cancer chemotherapy. Intratumoral TS protein expression before the chemoradiation therapy has been observed to inversely correlate with the response to 5-FU chemotherapy. Patients with low TS levels have better clinical outcome than those with high TS levels. Detecting the intratumoral TS levels is important for patients who are going to receive 5-FU-based chemotherapy, as these can be used to forecast the efficacy of chemotherapy. However, the classical assay for TS-activity determination (high-performance liquid chromatography with output monitored by radioactive flow detector) is tedious and expensive. A simple way to detect the TS levels is necessary. A research article would be published on January 28, 2008 in the World Journal of Gastroenterology addresses this question.

Immunoreactivity score (IRS) is a semiquantitative analysis for detecting the immunostaining results. Dr.Wei-Xing Wang and colleagues used monoclonal antibody TS106 to detect the TS protein in the paraffin-embedded specimens. The samples came from 68 colonic neoplasms of Han Chinese patients. At the same time, the team also observed the link between TS genotype and IRS of TS. Three genotypes of TS were found: 2R/2R (n = 6), 2R/3R (n = 22) and 3R/3R (n = 40). Patients who were homozygous for triple-repeated (3R/3R) sequences showed significantly higher IRS of TS than patients who were homozygous for double-repeated (2R/2R) sequences or heterozygous patients (2R/3R), but no statistical significance of IRS in cancer tissues was observed between 2R/3R genotype and 2R/2R genotype. These results suggested TS genotype may be a genetic factor which can be used to predict the patients response to 5-FU-based chemotherapy. The data might offer an advantage for selection of Chinese cancer patients to receive fluoropyrimidines therapy.


Posted by: Sue    Source




Did you know?
5-fluorouracil (5-FU) is a common chemotherapeutical drug. It exerts its antitumor effect through competitive thymidylate synthase (TS) inhibition. Thymidylate synthase (TS) catalyses deoxyuridine-5-monophosphate (dUMP) to 2-deoxythymydine-5-monophosphate (dTMP). It is the only de novo source of thymidylate, an essential precursor of DNA biosynthesis. In the 5-untranslated region of TS gene, there a unique tandem repeated sequence. There are three predominant genotypes of TS: (1) Homozygous with two tandem repeats (2R/2R); (2) homozygous with three tandem repeats (3R/3R); (3) heterozygous with both alleles (2R/3R). It was reported that TS genes with the triple repeats have higher expression activity than those with double repeats in vitro and in vivo.

Medicineworld.org: 5-fluorouracil in colonic neoplasm?

Main Page| Cancer blog| Cancer blogs list| Lung cancer blog| Colon cancer blog| Prostate cancer blog| Breast cancer blog| Diabetes watch blog| Heart watch blog| Allergy blog| Bladder cancer blog| Cervical cancer blog| Colon cancer news blog| Diabetes news blog| Esophageal cancer blog| Gastric cancer blog| Health news blog| Heart news blog| Infectious disease blog| Kidney watch blog| Lung disease blog| Lung cancer news blog| Mesothelioma blog| Neurology blog| Breast cancer news blog| OBGYN blog| Ophthalmology blog| Ovarian cancer blog| Cancer news blog| Pancreas cancer blog| Pediatrics blog| Prostate cancer news blog| Psychology blog| Research blog| Rheumatology blog| Society news blog| Uterine cancer blog| Weight watch blog|

Copyright statement
The contents of this web page are protected. Legal action may follow for reproduction of materials without permission.