Nutritional and metabolic aspects of gastrointestinal cancer

Role of CYP2E1 genotypes in susceptibility to colorectal cancer in the Kashmiri population

Cytochrome P450 2E1 (CYP2E1) is a key enzyme involved in the metabolic activation of procarcinogens such as N-nitrosoamines and low-molecular-weight organic compounds. The main aim of this study was to determine whether CYP450 2E1 polymorphisms are associated with the risk of colorectal cancer (CRC). We investigated the genotype distribution of the CYP2E1 gene RsaI and a 96-base pair (bp) insertion in 86 CRC cases in comparison with 160 healthy subjects. We found the frequency of the CYP2E1 RsaI genotype to be 53.5 per cent (46/86) for c1/c1, 17.4 per cent (15/86) for c1/c2 and 29.1 per cent (25/86) for c2/c2, and the CYP2E1 98-bp insertion frequencies to be 63.9 per cent (55/86) for non-insertion (i/i), 22.1 per cent (19/86) for heterozygous insertion (i/I) and 36.0 per cent (12/86) for homozygous insertion (I/I) among CRC cases. We also found the CYP2E1 RsaI c2/c2 and CYP2E1 98-bp heterozygous i/I genotypes to be significantly associated with an increased risk of CRC (p = 0.01). We suggest that CYP2E1 polymorphisms are involved in the susceptibility to developing CRC in the ethnic Kashmiri population.

Association and haplotype analysis of prostate stem cell antigen with gastric cancer in Tibetans

Genetic factors are known to be important in the development of gastric cancer (GC). Prostate stem cell antigen (PSCA) has been shown to be expressed in diffuse-type GC, and PSCA variation is associated with susceptibility to diffuse-type GC in Japanese and Korean populations. The aim of this study was to investigate the association between PSCA gene polymorphisms and GC in a Tibetan population. We analyzed single-nucleotide polymorphisms of the PSCA gene in 196 patients with GC and 246 controls in a Tibetan population, using a polymerase chain reaction/ligase detection reaction test. The rs2294008 C/T polymorphism of the PSCA gene was significantly associated with the susceptibility to GC. The CT genotype was associated with a significantly higher risk of GC when compared with the CC genotype (odds ratio [OR] = 1.50; 95% confidence interval [CI], 1.01-2.23). Patients carrying the T allele had a significantly higher risk for developing GC compared with individuals carrying the C allele (OR = 1.34; 95% CI, 1.00-1.79). Haplotype analyses showed that CA haplotype was associated with a significantly decreased risk of GC when compared with the CG haplotype (OR = 0.47; 95% CI, 0.24-0.93). Our data indicate that PSCA gene polymorphisms may be associated with GC in Tibetans.

Relative and absolute cancer mortality of women in agriculture in northern Italy

Most studies of cancer risk related to agricultural exposures have focused on male operators. Cancer mortality in a cohort of 38 962 women engaged in agriculture (Province of Forlì, 1969-1993) was compared with that of the rest of the female residents using the ratio of age-standardized (Europe) mortality rates (ASR) with 95% confidence interval (CI). Moreover, mortality time trends in both subsets of the population were evaluated. The cohort yielded 798 439 person-years with 2397 cancer deaths. Total ASR ratio was 0.86 (95% CI 0.80-0.92). Only gastric cancer was associated with a significant but declining excess mortality (ASR ratio 1.26; 95% CI 1.11-1.43). Total ASR ratio decreased from 1.07 (95% CI 0.95-1.20) in 1969-1976 to 0.74 (95% CI 0.66-0.82) in 1985-1993. This resulted from a downward mortality trend restricted to the cohort. In particular, mortality from cancers of the oesophagus, stomach and colon/rectum decreased more steeply in the cohort. Mortality from liver cancer decreased only in the cohort. Mortality from cancers of the pancreas, lung, breast, bladder and skin melanoma remained stable in the cohort whilst increasing in the rest of the population. In conclusion, risk excesses previously reported were not confirmed. Agricultural workers qualified as a subset of the female population with atypical, favourable epidemiologic characteristics.

Cancer mortality in a cohort of male agricultural workers from northern Italy

Cancer mortality in a cohort of 36,579 Italian male agricultural workers (Province of Forlì, 1969-1993) was compared with that of the rest of male population using the ratio of age-standardized (Europe) mortality rates (ASR) with the 95% confidence interval (CI). The cohort yielded 707,496.3 person-years with 3684 cancer deaths. Total ASR ratio was 0.85 (95% CI = 0.81-0.90). A significant excess mortality was observed only for gastric cancer (1.25; 1.13-1.39). Reduction in total cancer mortality was restricted to farm owners (0.83; 0.79-0.88), whereas excess gastric cancer mortality involved both farm owners (1.23; 1.11-1.37) and farm workers (1.32; 1.10-1.58). ASR ratio for gastric cancer decreased from 1.58 (1.34-1.86) in 1969-1976 to 0.97 (0.80-1.19) in 1985-1993. In conclusion, the only positive finding in this cohort of male agricultural workers was a generalized but declining excess mortality from gastric cancer.

Risk factors for the gastric cardia cancer: a case-control study in Fujian Province

AIM

The incidence of gastric cardia cancer has greatly increased in the past 2-3 decades, however, the risk factors for the disease are still not clearly understood. The investigations among Chinese population on the risk factors of gastric cardia cancer were also scarcely reported. We therefore conducted a case-control study in Fujian province, China, to investigate the potential risk and protective factors of this disease.

METHODS

191 cardia and 190 non-cardia gastric cancer cases, and a total of 222 control cases were included in this study. Standard questionnaires were used in collecting epidemiological factors and the data were then analyzed by the unconditional logistic regression model.

RESULTS

As the factors such as age, gender, smoking, alcohol consumption, and family history of gastric cancer were controlled, a multivariable analysis was conducted, which revealed that there was a significant correlation between the dietary habits such as irregular meal, over and fast eating, and the gastric cardia cancer with the odds ratios (ORs) of 4.2 (95 % confidence interval: 2.3-7.7), 4.7 (2.1-10.8), and 2.7 (1.3-5.3) respectively. Other correlations were also observed between the gastric cardia cancer and the consumption of salty fish or pickled vegetable, smoking, and the family cancer history with the ORs of 5.5 (1.4-19.5), 1.8 (1.0-3.0), 2.1 (1.3-3.5), and 3.8 (2.3-6.2) respectively. In contrast, the negative correlations were found existing between the intake of fresh vegetables and fruits, the use of refrigerator, and the gastric cardia cancer, with the ORs of 0.4 (0.2-0.9), 0.2 (0.1-0.5), and 0.2 (0.1-0.4), respectively. However, dietary habits were associated less with non-cardia gastric cancer compared with its cardia counterpart.

CONCLUSION

Dietary habits might be one of the risk factors for the cardia carcinogenesis among Chinese population.

Cytochrome P450 2E1 genetic polymorphism and gastric cancer in Changle, Fujian Province

AIM: Genetic polymorphism in enzymes of carcinogen metabolism has been found to have the influence on the susceptibility to cancer. Cytochrome P450 2E1 (CYP2E1) is considered to play an important role in the metabolic activation of procarcinogens such as N-nitrosoamines and low molecular weight organic compounds. The purpose of this study is to determine whether CYP450 2E1 polymorphisms are associated with risks of gastric cancer.

METHODS: We conducted a population based case-control study in Changle county, Fujian Province, a high-risk region of gastric cancer in China. Ninety-one incident gastric cancer patients and ninety-four healthy controls were included in our study. Datas including demographic characteristcs, diet intake, and alcohol and tobacco consumption of indivduals in our study were completed by a standardized questionnaire. PCR-RFLP revealed three genotypes:heterozygote (C1/C2) and two homozygotes (C1/C1 and C2/C2) in CYP2E1.

RESULTS: The frequency of variant genotypes (C1/C2 and C2/C2) in gastric cancer cases and controls was 36.3% and 24.5%, respectively. The rare homozygous C2/C2 genotype was found in 6 indivduals in gastric cancer group (6.6%), whereas there was only one in the control group (1.1%). However, there was no statistically significan difference between the two groups (two-tailed Fisher’s exact test, P = 0.066). Indivduals in gastric cancer group were more likely to carry genotype C1/C2 (odds ratio, OR = 1.50) and C2/C2 (OR = 7.34) than indivduals in control group (χ² = 4.597, for trend P = 0.032). The frequencies of genotypes with the C2 allele (C1/C2 and C2/C2 genotypes) were compared with those of genotypes without C2 allele (C1/C1 genotype) among indivduals in gastric cancer group and control group according to the pattern of gastric cancer risk factors. The results show that indivduals who exposed to these gastric cancer risk factors and carry the C2 allele seemed to have a higher risk of developing gastric cancer.

CONCLUSION: Polymorphism of CYP2E1 gene may have some effct in the development of gastric cancer in Changle county, Fujian Province.

Glutathione S-transferases M1, T1 genotypes and the risk of gastric cancer: A case-control study

AIM: Glutathione S-transferases (GSTs) are involved in the detoxification of many potential carcinogens and appear to play a critical role in the protection from the effects of carcinogens. The contribution of glutathione S-transferases M1 and T1 genotypes to susceptibility to the risk of gastric cancer and their interaction with cigarette smoking are still unclear. The aim of this study was to determine whether there was any relationship between genetic polymorphisms of GSTM1 and GSTT1 and gastric cancer.

METHODS: A population based case-control study was carried out in a high-risk area, Changle County, Fujian Province, China. The epidemiological data were collected by a standard questionnaire and blood samples were obtained from 95 incidence gastric cancer cases and 94 healthy controls. A polymerase chain reaction method was used to detect the presence or absence of the GSTM1 and GSTT1 genes in genomic DNA. Logistic regression model was employed in the data analysis.

RESULTS: An increase in risk for gastric cancer was found among carriers of GSTM1 null genotype. The adjusted odds ratio (OR) was 2.63 [95% Confidence Interval (95%CI) 1.17-5.88], after controlling for age, gender, cigarette smoking, alcohol drinking, and fish sauce intake. The frequency of GSTT1 null genotype in cancer cases (43.16%) was not significantly different from that in controls (50.00%). However, the risk for gastric cancer in those with GSTM1 null and GSTT1 non-null genotype was significantly higher than in those with both GSTM1 and GSTT1 non-null genotype (OR = 2.77, 95%CI 1.15-6.77). Compared with those subjects who never smoked and had normal GSTM1 genotype, ORs were 1.60 (95%CI: 0.62-4.19) for never smokers with GSTM1 null type, 2.33 (95%CI 0.88-6.28) for smokers with normal GSTM1, and 8.06 (95%CI 2.83-23.67) for smokers with GSTM1 null type.

CONCLUSIONS: GSTM1 gene polymorphisms may be associated with genetic susceptibility of stomach cancer and may modulate tobacco-related carcinogenesis of gastric cancer.

Nutritional and metabolic aspects of gastrointestinal cancer

The profound impact of nutrition and nutritional support on the development and clinical outcome of gastrointestinal cancer is undeniable. However, scientific investigation into this area is recent, and many questions remain unanswered. While the importance of 'good nutrition' is unchallenged, details relating to which patients should receive nutritional support, when they should receive it, and what type of support they should receive are not known. Recent prospective randomized clinical trials and meta-analysis have provided conflicting results. This review summarizes the results of the published studies that have addressed these issues, and provides specifics regarding the current role of nutritional support in clinical care, and the prospects for future research.