Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0038362 (stomatitis)
 8,852 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

5-Fluorouracil (5-FU) is an analogue of pyrimidine nucleosides that is widely used in the treatment of head and neck, breast, ovarian, and colon cancer. Stomatitis, diarrhea, dermatitis, and myelosuppression are the main toxicities of 5-FU. A less frequent side effect that is becoming more recognized is neurologic toxicity. Dihydropyrimidine dehydrogenase (DPD) is the rate-limiting enzyme in the catabolism of 5-FU. DPD deficiency follows an autosomal recessive pattern of inheritance, and its prevalence is estimated to be 3%. Cancer patients who are receiving 5-FU treatment and are DPD deficient can develop severe side effects. The neurologic toxicity can vary from being mild to severe and prolonged. We describe the side effects of 5-FU in a colon cancer patient who suffered severe mucositis, desquamating dermatitis, prolonged myelosuppression, and neurologic toxicity that required admission to the intensive care unit. The patient remained hospitalized for 3 months. Recovery from the side effects was complete 4 months after the last 5-FU treatment. Subsequent testing revealed that this patient has an extremely low level of DPD activity (0.015 nmol/min/mg protein; mean, 0.189 nmol/min/mg protein). Because neurologic toxicity is becoming more recognized and DPD affects the catabolism of 5-FU, we discuss management issues and the use of new DPD inhibitors. We also discuss whether screening for DPD deficiency is warranted to identify patients at risk for severe toxicities from 5-FU treatment.
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PMID:Prolonged severe 5-fluorouracil-associated neurotoxicity in a patient with dihydropyrimidine dehydrogenase deficiency. 1009 59

In humans, 80-90% of an administered dose of 5-fluorouracil (5-FU) is degraded by dihydropyrimidine dehydrogenase (DPD; EC 1.3.1.2), the initial rate-limiting enzyme in pyrimidine catabolism. Cancer patients with decreased DPD activity are at increased risk for severe toxicity including diarrhea, stomatitis, mucositis, myelosuppression, neurotoxicity, and, in some cases, death. We now report the first known cancer patient who developed life-threatening complications after treatment with topical 5-FU and was shown subsequently to have profound DPD deficiency. RT-PCR and genomic PCR methodologies were used to identify a G to A mutation in the GT 5' splicing recognition sequence of intron 14, resulting in a 165-bp deletion (corresponding to exon 14) in this patient's DPD mRNA. Immunoprecipitation and Western blot analysis were then used to demonstrate that the aberrant DPD mRNA is translated into a nonfunctional DPD protein that is ubiquitinated. We conclude that the presence of this metabolic defect combined with topical 5-FU (a drug demonstrating a narrow therapeutic index) results in the unusual presentation of life-threatening toxicity after treatment with a topical drug. These data further suggest that degradation by the ubiquitin-proteosome-mediated system plays a role in the elimination of the DPD protein.
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PMID:Life-threatening toxicity in a dihydropyrimidine dehydrogenase-deficient patient after treatment with topical 5-fluorouracil. 1047 70