ABSTRACT
Worldwide, colorectal cancer (CRC) is the third most common cancer, with the highest mortality rates occurring in Central Europe. The use of chemotherapy to treat CRC is limited by the inter-individual variability in drug response and the development of cancer cell resistance. ATP-binding cassette (ABC) transporters play a crucial role in the development of resistance by the efflux of anticancer agents outside of cancer cells. The aim of this study was to explore transcript levels of all human ABCs in tumours and non-neoplastic control tissues from CRC patients collected before the first line of treatment by 5-fluorouracil (5-FU)-containing regimen. The prognostic potential of ABCs was evaluated by the correlation of transcript levels with clinical factors. Relations between transcript levels of ABCs in tumours and chemotherapy efficacy were also addressed. The transcript profile of all known human ABCs was assessed using real-time polymerase chain reaction with a relative standard curve. The majority of the studied ABCs were down-regulated or unchanged between tumours and control tissues. ABCA12, ABCA13, ABCB6, ABCC1, ABCC2 and ABCE1 were up-regulated in tumours versus control tissues. Transcript levels of ABCA12, ABCC7 and ABCC8 increased in direction from colon to rectum. Additionally, transcript levels of ABCB9, ABCB11, ABCG5 and ABCG8 followed the reverse significant trend, i.e. a decrease in direction from colon to rectum. The transcript level of ABCC10 in tumours correlated with the grade (P = 0.01). Transcript levels of ABCC6, ABCC11, ABCF1 and ABCF2 were significantly lower in non-responders to palliative chemotherapy in comparison with responders. The disease-free interval of patients treated by adjuvant chemotherapy was significantly shorter in patients with low transcript levels of ABCA7, ABCA13, ABCB4, ABCC11 and ABCD4. In conclusion, ABCC11 may be a promising candidate marker for a validation study on 5-FU therapy outcome.
Subject(s)
ATP-Binding Cassette Transporters/genetics , Colorectal Neoplasms/genetics , Aged , Antineoplastic Agents/therapeutic use , Case-Control Studies , Chemotherapy, Adjuvant , Colon/metabolism , Colorectal Neoplasms/drug therapy , Colorectal Neoplasms/mortality , Disease Progression , Female , Gene Expression Regulation, Neoplastic , Humans , Male , Middle Aged , Multidrug Resistance-Associated Protein 2 , Neoplasm Metastasis , Pilot Projects , Prognosis , RNA, Messenger/genetics , Real-Time Polymerase Chain Reaction , Rectum/metabolism , Reverse Transcriptase Polymerase Chain Reaction , Survival RateABSTRACT
AIM: Ornithine decarboxylase (ODC) is a modifier of adenomatous polyposis coli-dependent tumourigenesis. The G316 > A polymorphism in intron 1 of the ODC gene lies between two myc-binding domains and alters the expression of the gene to affect polyamine metabolism. This variant may be associated with recurrence of colorectal adenoma. We examined whether this variant also modified the susceptibility to sporadic colorectal cancer (CRC). METHOD: The G316 > A variant was analysed in a large (n = 754) CRC case-controlled series of hospital patient volunteers (n = 627) in the Czech Republic, and the relationship with cancer risk was estimated by conditional logistic regression. RESULTS: After adjusting for age and sex, G316 > A was associated with no decrease in CRC risk for either heterozygotes [odds ratio 0.98, 95% confidence interval (CI) 0.77-1.23] or rare allele homozygotes (odds ratio 0.92, 95% CI 0.61-1.37). CONCLUSION: The G316 > A functional variant in the ODC gene is unlikely to make much impact on reducing CRC risk regardless of the reduction in risk found for the recurrence of colorectal adenoma.
Subject(s)
Carcinoma/genetics , Colonic Neoplasms/genetics , Ornithine Decarboxylase/genetics , Polymorphism, Single Nucleotide , Rectal Neoplasms/genetics , Adult , Aged , Aged, 80 and over , Case-Control Studies , Czech Republic , Female , Genotype , Humans , Introns , Logistic Models , Male , Middle AgedABSTRACT
UNLABELLED: Pancreatic cancer represents one of the biggest problems of current oncology. The risk factors of pancreatic cancer development, as well as factors affecting survival are poorly understood. Since biotransformation enzymes modify detoxification of carcinogens, we supposed, that arelationship between their polymorphism and the risk of pancreatic cancer development and eventually its clinical outcome may exist.
Associations of so far not studied cytochrome P450 1B1 (CYP1B1) polymorphisms with pancreatic cancer risk were investigated by case-control study. Atotal of 754 participants were recruited during study period. All patients were followed to determine their treatment and overall survival.
Carriers of rare genotype Val/Val in codon 432 of CYP1B1 (rs1056836) were under significantly lower risk of pancreatic cancer than wild type carriers (p=0.035). Carriers of heterozygous genotype (p=0.033) and rare allele Val (p=0.015) were also under lower risk than wild type carriers. When histology-verified patients were analyzed separately, even more significant associations were found (p=0.016, p=0.009, p=0.003, respectively). On the contrary, CYP1B1 polymorphism in codon 453 (rs1800440) did not significantly associate with pancreatic cancer risk. Median survival of patients with rare homozygous genotype Val/Val in CYP1B1-codon 432 was longer but not significantly different from those with wild-type homozygotes. The same was true for CYP1B1-codon 453 wild-type homozygotes in comparison with Ser/Ser rare homozygotes.
CYP1B1 polymorphism in codon 432 seems to modify the risk of pancreatic cancer development and should be further studied. KEYWORDS: Pancreatic cancer, CYP1B1, polymorphism, risk, survival.
