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Purpose: The primary aim was to respectively evaluate PLA2G4A mutants modifying protective effect of tea consumption against colorectal cancer (CRC), colon and rectal cancer., Methods: All participants were recruited from January 2006 to April 2008. The information about tea consumption was collected by a structured questionnaire. CRC patients were diagnosed based on histology. Four single-nuclear polymorphisms (SNPs) in PLA2G4A gene were selected. Multiple logistic regression models were used for assessing the joint effects between tea consumption and SNPs on CRC, colon and rectal cancer., Results: Three hundred patients with CRC and 296 controls well-matched were used in the final analyses. The significant individual associations between four SNPs (rs6666834, rs10911933, rs4650708 and rs7526089) and CRC were not observed. However, their CTAC haplotype was significantly associated with the increased risk of CRC (OR = 3.06; 95%CI = 1.52-6.19), compared with TCAC haplotype. Drinking tea was correlated with a decreased risk of CRC after adjustment for covariates (OR = 0.61; 95%CI = 0.39-0.97). Meanwhile, compared with no-tea drinkers with TT/CT genotype of rs6666834, tea drinkers with TT/CT or CC had significant lower risk of CRC (OR = 0.6, 95%CI = 0.36-1.00 for TT/CT; 0.38, 0.19-0.74 for CC). The joint effects between the remaining three SNPs and drinking tea on CRC were observed as well. Similar findings were observed on colon and rectal cancers., Conclusions: Tea consumption and haplotype of mutants in PLA2G4A gene were respectively associated with the risk of CRC. PLA2G4A mutants modified the protective effect of tea consumption against CRC, colon and rectal cancers in Chinese population.

The xeroderma pigmentosum complementation group C (XPC) is responsible for removal of bulky helix-distorting DNA lesions. Several polymorphisms of XPC gene may modulate the colorectal cancer (CRC) susceptibility. We assessed the association of XPC Lys939Gln (A/C), Ala499Val (C/T), and PAT (-/+) polymorphisms with CRC risk in a population-based case-control study which included 421 CRC patients and 845 controls. For Lys939Gln, the CC genotype was associated with a significantly increased risk of CRC (odds ratio (OR)=1.5; 95% confidence interval (CI)=1.0-2.2) compared with the AA genotype. The subjects with PAT +/+ genotype had a significantly increased risk of CRC (OR=1.5; 95% CI=1.0-2.3), compared with those with PAT-/- genotype. Though no significant association between Ala499Val and CRC risk was observed, we found that individuals carrying the CT+TT genotypes showed a significantly decreased risk of rectal cancer (OR=0.7; 95% CI=0.5-1.0). Additionally, the haplotype C+C was associated with a significantly increased CRC risk (OR=1.3; 95% CI=1.0-1.6), compared with the most common haplotype A-T. Further, individuals with four or more risk alleles exhibited a significantly increased risk of CRC (OR=1.4; 95% CI=1.0-2.0), with a significant gene-dosage effect (P for trend=0.038). Besides, never tea drinking was associated with a significantly increased risk of CRC (OR=2.3; 95% CI=1.7-3.3). Our results suggest that the XPC polymorphisms may modulate CRC susceptibility independently or jointly, and tea drinking has a protective effect on CRC., (Copyright © 2010 Wiley-Liss, Inc.)

The detection of benzo(a)pyrene (BaP), a strong carcinogen, in edible oil has been widely reported. This work studied the concentration of BaP in different parts of tea seeds generated during roasting from a new perspective. A novel method was established and used to calculate the actual generated concentration of BaP, which is different from the previous direct determination of BaP concentration and also takes into account the concentration of the lost BaP. The results showed that the loss rate of BaP in husks was the highest (92.7%), while that in the peeled tea seeds was the lowest (66.9%). Conversely, the generated concentration of BaP in peeled seeds was the highest (6.7 μg·kg−1), while that in husks was the lowest (2.8 μg·kg−1). The change in concentration of BaP during roasting was mainly related to the components of different parts of tea seeds. Finally, the lost BaP-d12 in tea seeds was detected in other parts of the semi-closed simplified model, which confirmed that BaP will migrate during roasting. This work emphasised that it was necessary to modify the calculation method for the generated concentration of BaP in food during thermal processing, which will be helpful to explore the generation mechanism of BaP. [ABSTRACT FROM AUTHOR]

To reduce the contamination of benzo(a)pyrene (BaP) in refined oil during processing, the degumming, deacidification, decolorization, and deodorization processes are optimized to remove BaP and improve the quality of tea seed oil. The results show that decolorization is the most obvious refining process of removing BaP, which is mainly due to the addition of activated carbon and decolorization time. In addition, to ensure the quality of refined tea seed oil and remove BaP, the deodorization temperature and time should be strictly controlled. Comparing with crude oil, the removal rates of BaP in the optimized processes of degumming, deacidification, decolorization, and deodorization reached 16.26%, 18.36%, 92.76%, and 91.08%, respectively. The optimized refining processes can significantly decrease the level of BaP from 9.53 ± 0.02 µg kg−1 in crude tea seed oil to 0.85 ± 0.10 µg kg−1 in refined tea seed oil, and the other physicochemical indexes are in line with the international standard for refined oil. This study can provide useful guidance for the safe processing of refined tea seed oil. Practical Applications: BaP is an internationally recognized carcinogen. In view of the current situation of commercial edible oil being contaminated by BaP, it is particularly important to control the level of BaP in the refining process. To remove BaP while improving the quality of oil, the processes of degumming, deacidification, decolorization, and deodorization of tea seed oil were optimized, and the best refining processes were determined. The results have important practical significance, which could help to reduce the level of BaP and provide a useful reference for the safe production of refined tea seed oil. [ABSTRACT FROM AUTHOR]