Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C1864663 (HCC)
 2,985 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Two recent screens for copy-number variations in the entire human genome found 12.4 gene copy number variations per person, including 2.5% of individuals with gains between 7q21.1 and 7q22.1, the chromosomal location of CYP3A4. CYP3A4 is involved in the metabolism of approximately 50% of all drugs, including many cancer chemotherapeutic agents. CYP3A4 gene copy was determined in DNA from 143 individuals: normal human livers, primary and secondary liver tumors, human hepatic cell lines, and immortalized cell lines representing eight ethnically diverse populations. CYP3A4 gene copy was normal in all but one sample, a primary human hepatocellular carcinoma cell line (TONG/HCC). Southern blots of TONG/HCC DNA revealed an approximate 10-fold increase in CYP3A and a corresponding increase in CYP3A mRNA expression and catalytic activity. Fluorescent in situ hybridization of TONG/HCC revealed specific amplification of the CYP3A4 gene on chromosome 7q21 but no amplification of the MDR1 gene that localizes 11.9 Mb upstream of CYP3A4. High resolution analysis of DNA copy number by comparative genomic hybridization confirmed amplification at 7q21.3-7q22. The amplicon spanned 1.7 Mb and contained 30 known genes, including the entire CYP3A locus. To determine whether CYP3A4 expression affected chemotherapeutic toxicity, LLC-PK1 cells were transduced with adenoviruses expressing CYP3A4 and P450 reductase. CYP3A4 conferred resistance to taxol, vinblastine and topotecan. These studies demonstrate that CYP3A4 copy number differences do not contribute to the normal variation in CYP3A4 expression. Tumors with increased CYP3A copy number (via amplification or increased chromosome 7q) would be expected to show reduced cytotoxicity to some chemotherapeutic drugs and potentially an increase in the outgrowth of drug resistant tumors.
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PMID:Increased CYP3A4 copy number in TONG/HCC cells but not in DNA from other humans. 1670 50

Despite considerable efforts no ideal treatment exists for HCC. The disease is usually detected late and few patients are candidates for potentially curative treatment options such as surgical resection or liver transplantation. Surgical resection is limited mostly by the impaired liver function in cirrhotic livers, whereas liver transplantation is limited by tumor size, multi-localized disease and, most important, by shortage of donor organs. TACE as a local ablative treatment is able to induce local disease control and to prolong survival and might even achieve survival similar to surgical resection. The high rates of recurrence of HCC after successful control of local tumor spread is the reason to consider that procedure as a non-curative treatment option. PEI and RFA are able to control local tumor growth, but cannot influence tumor recurrence or de novo tumor growth. Systemic therapies need to be investigated in large randomized trials, especially to evaluate the use of somatostain analogues, HMGCoA reductase inhibitors, or other drugs such as rapamycin or inhibitors of vascular endothelial growth factor (VEGF).
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PMID:Hepatocellular carcinoma--rising incidence, changing therapeutic strategies. 1693 43