Plasminogen activator inhibitor 1 (PAI-1) levels and gene promoter polymorphisms in subjects with colorectal cancer

The high level of plasminogen activator inhibitor 1 (PAI-1) in colorectal cancer predicts poor prognosis for patients. The insertion (5G)/deletion (4G) polymorphism (the 4G/5G polymorphism) and G-->A single base substitution (the G/A polymorphism) located at promoter of PAI-1 gene may have functional significance in regulation of its expression. In the present work the level of PAI-1, distribution of genotypes and frequency of alleles of the 4G/5G and G/A polymorphisms in samples of cancer tissue and normal mucosa as well as in blood were investigated. Blood, tumor and normal tissues were obtained from 40 patients with colorectal cancer. The 4G/5G and G/A polymorphism were determined by PCR amplification using the allele specific primers. The PAI-1 level was measured by enzyme linked immunosorbent assay (ELISA). The distribution of the genotypes of both polymorphisms did not differ significantly (p > 0.05) from those predicted by the Hardy-Weinberg distribution. There were no differences in the genotype distributions and allele frequencies between blood, normal mucosa samples and cancer tissue. The 4G/5G and G/A polymorphisms were in linkage disequilibrium. The average level of PAI-1 in tumor samples was significantly (p < 0.05) higher than in normal tissue. The results obtained indicate that a higher level of PAI-1 can be associated with colorectal cancer. On the other hand, in colon cancer, the 4G/5G and G/A polymorphisms are not linked with elevated levels of PAI-1 and therefore may not be used to predict colon cancer prognosis.