Regulatory cytokine gene polymorphisms and risk of colorectal carcinoma.

It is well established that cancer arises in chronically inflamed tissue, and this is particularly notable in the gastrointestinal tract. Classic examples include Helicobacter pylori-associated gastric cancer, hepatocellular carcinoma, and inflammatory bowel disease-associated colorectal cancer. Growing evidence suggests that these associations might be not casual findings. Focusing on individual cytokines has generated evidence that anti-inflammatory cytokine interleukin (IL)-10 and transforming growth factor-beta1 (TGF-beta1) may have a complex role in gastrointestinal carcinogenesis. As an example, IL-10-deficient mice develop severe atrophic gastritis and a chronic enterocolitis, developing colorectal cancer similar to human inflammatory bowel disease-associated neoplasia. TGF-beta1 is a multifunctional signaling molecule with a wide array of roles. Animal experiments suggest that TGF-beta1 plays a biphasic role in carcinogenesis by protecting against the early formation of benign epithelial growths, but promoting a significant stimulation of tumor growth invasion and metastasis during tumor progression. We assessed association of functional polymorphisms (-1082G/A; -592C/A) and TGF-beta1 (-509C/T; +869C/T) influencing the IL-10 production to colorectal cancer risk in a case-control study of 62 patients and 124 matched controls. No significant differences were observed among cancer patients and controls for IL-10 -1082G/A; -592C/A genotype frequencies. Evaluation of odds ratios (OR) for the TGF-beta1 +869C/T genotypes showed a significant increased risk for individuals bearing +869CC genotype compared to +869CT- and +869TT-positive individuals. These results suggest that the +869C allele, responsible for a Leu-->Pro substitution in the signal peptide sequence of the TGF-beta1 protein, may have a predisposing role in the development of colorectal cancer.

Cytokine gene polymorphisms and breast cancer susceptibility.

Human breast cancer (BC) is characterized by a considerable clinical heterogeneity. Steroid hormone receptor expression and growth factor receptor expression have been considered suitable diagnostic and prognostic markers, whereas mutations of oncosuppressor and gatekeeper genes have been found associated with an increased risk for this malignancy. To evaluate the role that polymorphisms of genes involved in the regulation of inflammatory response might play in BC susceptibility, we investigated associations between cytokine functionally relevant polymorphisms in 84 BC patients compared to 110 age- and sex-matched controls. TNF-alpha (-308G/A), TGF-beta1 (+869C/T), IL-10 (-1117G/A; -854C/T; -627C/A), and IFN-gamma (874T/A) single nucleotide polymorphisms (SNPs) were identified by sequence-specific primers (SSP)-PCR or restriction fragment length polymorphism (RFLP)-PCR. Genotype or haplotype distributions for each polymorphisms were consistent with the HWE in these populations. We were unable to demonstrate differences in genotype or allele frequencies between patient and control groups. Data obtained in this study indicate that none of the cytokine SNPs studied is likely to have predisposing or protective effects on BC susceptibility. On the other hand, both positive and negative association with BC have been reported for some of the studied genotypes by different research groups. In conclusion, further studies involving larger numbers of subjects are required.