Polymorphisms in the genes of the urokinase plasminogen activation system in relation to colorectal cancer

Genetic Variants in RASSF1 (rs2073498), SERPINE1 (rs1799889), and EFNA1 (rs12904) Are Associated with Susceptibility in Mexican Patients with Colorectal Cancer: Clinical Associations and Their Analysis In Silico

Background/Objectives: Colorectal cancer (CRC) is the second leading cause of cancer death worldwide. Variants in genes that regulate processes such as apoptosis and angiogenesis play a significant role in CRC. The objective of this study is to investigate the possible association between RASSF1 (rs2073498), SERPINE1 (rs1799889), EFNA1 (rs12904), and RAD51 (rs1801320) variants and clinicopathological characteristics of Mexican patients with CRC. Methods: DNA of peripheral blood samples was obtained from 631 individuals (349 patients and 282 control individuals). The RASSF1 (rs2073498), SERPINE1 (rs1799889), EFNA1 (rs12904), and RAD51 (rs1801320) variants were genotyped by polymerase chain reaction-restriction fragment length polymorphism (PCR-RFLP). The association was calculated using the odds ratio (OR) test. p-values were adjusted by the Bonferroni test (0.0125). In silico analysis programs, including Combined Annotation Dependent Depletion (CADD), Polymorphism Phenotyping-2 (PolyPhen-2), and Gene Expression Profiling Interactive Analysis (GEPIA), were conducted to predict the functional impact of these variants. Results: Patients carrying the G/A genotype of the RASSF1 (rs2073498) variant showed an association with CRC characteristics, including TNM stages and tumor location (OR > 2.5, p = 0.001). Regarding the SERPINE1 (rs1799889) variant, patients carrying the 5G/4G genotype showed an association between TNM stages and tumor location in the rectum (OR > 1.5, p ≤ 0.05). Patients with the G/G genotype for the EFNA1 (rs12904) variant showed an association with TNM stages and rectal tumor location (OR > 2.0, p = 0.001). The RAD51 (rs1801320) variant had no association with colorectal cancer. Conclusions: RASSF1 (rs2073498), SERPINE1 (rs1799889), and EFNA1 (rs12904) variants significantly influence colorectal cancer risk.

PAI-1 Polymorphisms Have Significant Associations With Cancer Risk, Especially Feminine Cancer

BACKGROUND

The plasminogen activator inhibitor-1 (PAI-1) was found in many types of tumor cells, which involved in tumorigenesis. Some studies investigated the associations between PAI-1 polymorphisms and various cancers, but the results were inconsistent. So this study did a meta-analysis to assess the strength of relationship between PAI-1 and cancer.

METHODS

Articles that meet the requirements were searched from PubMed, EMBASE, MEDLINE, Scopus, CNKI, Wanfang and SinoMed electronic databases before June 17th 2021. Stata version 11.2 was performed to merge the odds ratios (ORs) values and calculate 95% confidence intervals (CIs). Stratified analyses were assessed on the basis of types of cancer, ethnicity and source of the control group. Heterogeneity and sensitivity analysis were tested, and publication bias was also estimated. A meta-regression analysis was applied to explore sources of heterogeneity. The false-positive report probabilities (FPRP) and the Bayesian False Discovery Probability (BFDP) test were used to assess the credibility of statistically significant associations.

RESULTS

Ultimately, in this study, 33 eligible reports were included with 9550 cases and 10431 controls for the rs1799889 polymorphism, 5 reports with 2705 cases and 3168 controls for the rs2227631 polymorphism, and 4 reports with 2799 cases and 4011 controls for the rs2227667 polymorphism. The ORs and 95% CIs showed a statistically significant relationship between rs1799889 4G>5G polymorphism and cancer risk, especially in feminine cancer. The term refers to cancers that occur in the female reproductive system, such as ovarian, breast, endometrial and cervical cancer. Moreover, there was no association observed for the PAI-1 promoter A>G polymorphism (rs2227631 and rs2227667). In further subgroup analyses of 4G>5G polymorphism (rs1799889), an increased susceptibility to cancer was observed in Caucasians group and some types of cancer groups.

CONCLUSIONS

This article comes to a conclusion that the rs1799889 polymorphism might help to increase the risk of cancer; moreover, the susceptibility to feminine cancer is more evident.

Association between Five Common Plasminogen Activator Inhibitor-1 (PAI-1) Gene Polymorphisms and Colorectal Cancer Susceptibility

The plasminogen activator inhibitor-1 (PAI-1) is expressed in many cancer cell types and modulates cancer growth, invasion, and angiogenesis. The present study investigated the association between five PAI-1 gene polymorphisms and colorectal cancer (CRC) risk. Five PAI-1 polymorphisms (−844G > A [rs2227631], −675 4G > 5G [rs1799889], +43G > A [rs6092], +9785G > A [rs2227694], and +11053T > G [rs7242]) were genotyped using a polymerase chain reaction-restriction fragment length polymorphism assay in 459 CRC cases and 416 controls. Increased CRC risk was more frequently associated with PAI-1 −675 5G5G polymorphism than with 4G4G (adjusted odds ratio (AOR) = 1.556; 95% confidence interval (CI): 1.012–2.391; p = 0.04). In contrast, for the PAI-1 +11053 polymorphism, we found a lower risk of CRC with the GG genotype (AOR = 0.620; 95% CI: 0.413–0.932; p = 0.02) than with the TT genotype, as well as for recessive carriers (TT + TG vs. GG, AOR = 0.662; 95% CI: 0.469–0.933; p = 0.02). The +43AA genotype was associated with lower overall survival (OS) than the +43GG genotype. Our results suggest that the PAI-1 genotype plays a role in CRC risk. This is the first study to identify an association between five PAI-1 polymorphisms and CRC incidence worldwide.

The plasminogen activator inhibitor-1 paradox in cancer: a mechanistic understanding

The paradoxical pro-tumorigenic function of plasminogen activator inhibitor 1 (PAI-1, aka Serpin E1) in cancer progression and metastasis has been the subject of an abundant scientific literature that has pointed to a pro-angiogenic role, a growth and migration stimulatory function, and an anti-apoptotic activity, all directed toward promoting tumor growth, cancer cell survival, and metastasis. With uPA, PAI-1 is among the most reliable biomarkers and prognosticators in many cancer types. More recently, a novel pro-tumorigenic function of PAI-1 in cancer-related inflammation has been demonstrated. These multifaceted activities of PAI-1 in cancer progression are explained by the complex structure of PAI-1 and its multiple functions that go beyond its anti-fibrinolytic and anti-plasminogen activation activities. However, despite the multiple evidences supporting a pro-tumorigenic role of PAI-1 in cancer, and the development of several inhibitors, targeting PAI-1, has remained elusive. In this article, the various mechanisms responsible for the pro-tumorigenic functions of PAI-1 are reviewed with emphasis on its more recently described contribution to cancer inflammation. The challenges of targeting PAI-1 in cancer therapy are then discussed.

Plasminogen activator inhibitor-1 is associated with the metabolism and development of advanced colonic polyps

Implications of plasminogen activator inhibitor-1 (PAI-1) in colonic polyps remain elusive. A prospective study was conducted with 188 consecutive subjects who underwent colonoscopy at a tertiary referral center. Biochemical parameters, serum PAI-1 levels, PAI-1 single-nucleotide polymorphisms (rs-1799889), and colonic polyp profiles were analyzed at baseline and 24 and 48 weeks postpolypectomy. Of 188 patients (mean age: 56.8 years), 78.7% had adenomas; the median polyp number and size were 2 and 1.2cm, respectively. Multivariate analyses revealed the following baseline associations: PAI-1 levels (95% confidence interval [CI] for estimated β: 0.012-0.223) and polyp pathology (0.294-0.63) with polyp size; polyp size (0.085-0.498) and platelet count (0.013-0.027) with PAI-1 levels. At 24 weeks postpolypectomy, homeostasis model assessment-estimated insulin resistance (HOMA-IR) and platelet count were independently associated with PAI-1 levels. Among patients with colonic adenomas, baseline PAI-1 levels (95% CI odds ratio: 1.06-1.686; cut-off value: >10.65 ng/mL, area under curve: 0.662, P = 0.032) and the PAI-1-rs-17998894G/4G genotype (0.036-0.912) were associated with high-grade dysplasia. Compared with baseline levels, repeated measures analysis of variance showed that PAI-1 levels increased, with concurrent increased HOMA-IR indexes, but decreased alanine transaminase levels and polyp size in follow-up colonoscopies at 24 weeks postpolypectomy. PAI-1 returned to baseline levels, and HOMA-IRs and triglyceride/high-density lipoprotein-cholesterol ratios decreased at 48 weeks postpolypectomy. Taken together, serum PAI-1 levels were positively associated with colonic polyp size and high-grade dysplasia, which was modulated by the PAI-1-rs-17998894G/4G genotype. The beneficial postpolypectomy inflammatory and metabolic alterations might be transiently counter regulated by elevated PAI-1 levels, with a link to HOMA-IR.

Serum and tissue markers in colorectal cancer: State of art

Colorectal cancer (CRC) represents one of the most commonly diagnosed cancers worldwide. It is the second leading cause of cancer death in Western Countries. In the last decade, the survival of patients with metastatic CRC has improved dramatically. Due to the advent of new drugs (irinotecan and oxaliplatin) and target therapies (i.e. bevacizumab, cetuximab, panitumab, aflibercept and regorafenib), the median overall survival has risen from about 12 mo in the mid nineties to 30 mo recently. Molecular studies have recently widened the opportunity for testing new possible markers, but actually, only few markers can be recommended for practical use in clinic. In the next future, the hope is to have a complete panel of clinical biomarkers to use in every setting of CRC disease, and at the same time: 1) to receive information about prognostic significance by their expression and 2) to be oriented in the choice of the adequate treatment. Moreover, molecular analyses have shown that the natural history of all CRCs is not the same. Individual patients with same stage tumors may have different long-term prognosis and response to therapy. In addition, some prognostic variables are likely to be more important than others. Here we review the role of serum and tissue markers according to the recently published English literature. This paper is an extension of the article "Biological and clinical markers in colorectal cancer: state of art" by Cappellani A published in Jan 2010.

Association between the polymorphisms of urokinase plasminogen activation system and cancer risk: a meta-analysis

Purpose

The present study aimed to investigate the potential association between the urokinase plasminogen activation (uPA) system polymorphisms (rs4065, rs2227564, and rs344781) and cancer risk.

Methods

An extensive search was performed to identify published case–control studies on the association between the uPA system polymorphisms and cancer risk. Odds ratios (ORs) with 95% confidence intervals (CIs) were used to evaluate the relationship between the uPA system polymorphisms and cancer risk.

Results

A total of 20 studies comprising 7,037 cancer cases and 10,094 controls were identified and included in the present meta-analysis. Overall, significantly increased cancer risk was associated with the uPA polymorphism rs4065 (T vs C: OR 1.50, 95% CI: 1.19–1.89; TT vs CC: OR 4.63, 95% CI: 3.10–6.91; dominant model: OR 1.93, 95% CI: 1.60–2.33; recessive model: OR 3.02, 95% CI: 1.26–7.25) and the uPA receptor polymorphism rs344781 (T vs C: OR 1.13, 95% CI: 1.04–1.23; TC vs CC: OR 1.26, 95% CI: 1.06–1.49; TT vs CC: OR 1.35, 95% CI: 1.13–1.63; dominant model: OR 1.29, 95% CI: 1.10–1.52). No significant association was found between the uPA polymorphism rs2227564 and cancer risk. Subgroup analysis suggests that the T allele of the rs4065 (T allele vs C allele: OR 1.50, 95% CI: 1.19–1.89) and rs344781 polymorphisms (T allele vs C allele: OR 1.13, 95% CI: 1.04–1.23) was associated with increased cancer risk in Asians.

Conclusion

Our results suggest that the uPA polymorphism rs4065 and the uPA receptor polymorphism rs344781 are associated with increased cancer risk.

Association between Plasma Levels of Plasminogen Activator Inhibitor-1 and Colorectal Neoplasms

Background/Aims

Plasminogen activator inhibitor-1 (PAI-1) is important for tumor growth, Invasion, and metastasis. In this study, we investigated the relationship between plasma levels of PAI-1 and colorectal adenomas.

Methods

We reviewed the medical records of 3,136 subjects who underwent colonoscopy as a screening exam. The subjects were classified into a case group with adenomas (n=990) and a control group (n=2,146). Plasma PAI-1 levels were categorized into three groups based on tertile.

Results

The plasma levels of PAI-1 were significantly higher in adenoma cases than in controls (p=0.023). The prevalence of colorectal adenomas increased significantly with increasing levels of PAI-1 (p=0.038). In the adenoma group, advanced pathologic features, size, and number of adenomas did not differ among the three groups based on tertiles for plasma PAI-1 levels. Using multivariate analysis, we found that plasma level of PAI-1 was not associated with the risk of colorectal adenomas (p=0.675). Adjusted odds ratios for colorectal adenomas according to increasing plasma levels of PAI-1 were 0.980 (95% confidence interval [CI], 0.768 to 1.251) for the second-highest plasma level and 1.091 (95% CI, 0.898 to 1.326) for the highest level, compared with the lowest levels.

Conclusions

These results suggest that elevated plasma PAI-1 levels are not associated with the risk of colorectal neoplasms.

PAI-1 4G/5G polymorphism contributes to cancer susceptibility: evidence from meta-analysis

BACKGROUND

The plasminogen activator inhibitor-1 (PAI-1) is expressed in many cancer cell types and allows the modulation of cancer growth, invasion and angiogenesis. To date, studies investigated the association between a functional polymorphism in PAI-1 (4G/5G) and risk of cancer have shown inclusive results.

METHODS

A meta-analysis based on 25 case-control studies was performed to address this issue. Odds ratios (OR) with corresponding 95% confidence intervals (CIs) were used to assess the association. The statistical heterogeneity across studies was examined with I(2) test.

RESULTS

Overall, a significant increased risk of cancer was associated with the PAI-1 4G/4G polymorphism for the allele contrast (4G vs. 5G: OR = 1.10, CI = 1.03-1.18, I(2) = 49.5%), the additive genetic model (4G/4G vs. 5G/5G: OR = 1.21, CI = 1.06-1.39, I(2) = 51.9%), the recessive genetic model (4G/4G vs. 4G/5G+5G/5G: OR = 1.11, CI = 1.04-1.18, I(2) = 20.8%). In the subgroup analysis by ethnicity, the results indicated that individuals with 4G/4G genotype had a significantly higher cancer risk among Caucasians (4G/4G vs. 5G/5G: OR = 1.31, 95%CI = 1.09-1.59, I(2) = 59.6%; 4G/4G vs. 4G/5G: OR = 1.12, 95%CI = 1.04-1.21, I(2) = 3.6%; recessive model: OR = 1.12, 95%CI = 1.05-1.21, I(2) = 25.3%).

CONCLUSIONS

The results of the present meta-analysis support an association between the PAI-1 4G/5G polymorphism and increasing cancer risk, especially among Caucasians, and those with 4G allele have a high risk to develop colorectal cancer and endometrial cancer.

Aneuploidy-associated gene expression signatures characterize malignant transformation in ulcerative colitis

BACKGROUND

Malignant transformation in ulcerative colitis (UC) is associated with pronounced chromosomal instability, reflected by aneuploidy. Although aneuploidy can precede primary cancer diagnosis in UC for more than a decade, little is known of its cellular consequences.

METHODS

Whole-genome gene expression analysis was applied to noninflamed colon mucosa, mucosal biopsies of patients with UC, and UC-associated carcinomas (UCCs). DNA image cytometry was used to stratify samples into ploidy types. Differentially expressed genes (DEGs) were analyzed by Ingenuity Pathway Analysis and validated by real-time quantitative PCR.

RESULTS

Gene expression changes were more pronounced between normal mucosa and UC (2587 DEGs) than between UC and UCC (827 DEGs). Cytometry identified colitis patients with euploid or aneuploid mucosa biopsies, whereas all UCCs were aneuploid. However, 1749 DEGs distinguished euploid UC and UCCs, whereas only 15 DEGs differentiated aneuploid UC and UCCs. A total of 16 genes were differentially expressed throughout the whole sequence from normal controls to UCCs. Particularly, genes pivotal for chromosome segregation (e.g., SMC3 and NUF2) were differentially regulated along aneuploidy development.

CONCLUSIONS

The high number of DEGs between normal mucosa and colitis is dominated by inflammatory-associated genes. Subsequent acquisition of aneuploidy leads to subtle but distinct transcriptional alterations, revealing novel target genes that drive genomic instability and thus carcinogenesis. The gene expression signature of malignant phenotypes in aneuploid UC suggests that these lesions might need to be considered as severe as high-grade dysplasia.

PAI-1 promoter 4G/5G polymorphism (rs1799768) contributes to tumor susceptibility: Evidence from meta-analysis

Plasminogen activator inhibitor-1 (PAI-1), belonging to the urokinase plasminogen activation (uPA) system, is involved in cancer development and progression. The PAI-1 promoter 4G/5G polymorphism was shown to contribute to genetic susceptibility to cancer, although the results were inconsistent. To assess this relationship more precisely, a meta-analysis was performed. The electronic databases PubMed, Scopus, Web of Science and Chinese National Knowledge Infrastructure (CNKI) were searched; data were extracted and analyzed independently by two reviewers. Ultimately, 21 eligible case-control studies with a total of 8,415 cancer cases and 9,208 controls were included. The overall odds ratio (OR) with its 95% confidence interval (CI) showed a statistically significant association between the PAI-1 promoter 4G/5G polymorphism and cancer risk (4G/4G vs. 5G/5G: OR=1.25, 95% CI=1.07–1.47, P_{heterogeneity}=0.001; 4G/4G vs. 4G/5G+5G/5G: OR=1.10, 95% CI=1.03–1.17, P_{heterogeneity}=0.194; 4G/4G+4G/5G vs. 5G/5G: OR=1.17, 95% CI=1.01–1.35, P_{heterogeneity}=0.041). In further subgroup analyses, the increased risk of cancer was observed in a subgroup of Caucasians with regards to endometrial cancer. Our meta-analysis suggests that the PAI-1 4G/5G polymorphism most likely contributes to susceptibility to cancer, particularly in Caucasians. Furthermore, the 4G allele may be associated with an increased risk of endometrial cancer.

Clinical utility of level-of-evidence-1 disease forecast cancer biomarkers uPA and its inhibitor PAI-1

The prognostic and/or predictive value of the cancer biomarkers, urokinase-type plasminogen activator (uPA) and its inhibitor (plasminogen activator inhibitor [PAI]-1), determined by ELISA in tumor-tissue extracts, was demonstrated for several cancer types in numerous clinically relevant retrospective or prospective studies, including a multicenter breast cancer therapy trial (Chemo-N0). Consequently, for the first time ever for any cancer biomarker for breast cancer, uPA and PAI-1 have reached the highest level of evidence, level-of-evidence-1. At present, two other breast cancer therapy trials, NNBC-3 and Plan B, also incorporating uPA and PAI-1 as treatment-assignment tools are in effect. Furthermore, small synthetic molecules targeting uPA are currently in Phase II clinical trials in patients afflicted with advanced cancer of the ovary, breast or pancreas.

Clotting factor gene polymorphisms and colorectal cancer risk

PURPOSE

Increased coagulation has been associated with cancer onset and progression. Mainly small studies have addressed the association between clotting factor gene polymorphisms and the onset of colorectal cancer. We examined the association between six well-known clotting factor gene polymorphisms and colorectal cancer risk in a large case-control study.

PATIENTS AND METHODS

Factor V Leiden (rs6025), prothrombin G20210A (rs1799963), PAI-1 4G/5G (rs1799889), MTHFR 677C>T (rs1801133), fibrinogen gamma 10034C>T (rs2066865), and factor XIII Val34Leu (rs5985) were genotyped in 1,801 patients with colorectal cancer and 1,853 healthy controls from a large German population-based study. The risk of colorectal cancer associated with gene variants was determined by calculating odds ratios (ORs) and their 95% CIs using logistic regression.

RESULTS

Homozygous carriers of the prothrombotic factor V Leiden polymorphism showed a 5.8-fold increased risk (95% CI, 1.69 to 19.72) for colorectal cancer compared with noncarriers. A 30% reduced risk was found for heterozygous carriers of factor V Leiden (OR = 0.68; 95% CI, 0.52 to 0.90) and prothrombin G20210A (OR = 0.69; 95% CI, 0.49 to 0.96), implying an advantage for slightly increased thrombin generation. Carriers of the antithrombotic factor XIII Val34Leu polymorphism showed a 15% reduced risk of developing colorectal cancer (OR = 0.85; 95% CI, 0.74 to 0.97) compared with noncarriers. Our results did not support an effect of PAI-1 4G/5G, MTHFR 677C>T, and fibrinogen gamma 10034C>T on colorectal cancer risk.

CONCLUSION

Our results support a role of clotting factor polymorphisms and thereby the coagulation system in the risk of colorectal cancer.

SERPINE1 intron polymorphisms affecting gene expression are associated with diffuse-type gastric cancer susceptibility

BACKGROUND

A primary inhibitor of plasminogen activators, SERPINE1 (serpin peptidase inhibitor 1, clade E, member 1, also known as plasminogen activator inhibitor type 1), is an important regulator in tumorigenesis and is highly expressed in many cancers.

METHODS

Five tag single nucleotide polymorphisms (SNPs) and 1 insertion polymorphism within SERPINE1 were genotyped in 1101 unrelated Korean individuals (a case group of 612 patients with gastric cancer and a control group of 489 healthy individuals). Associations with susceptibility to diffuse-type gastric cancer (DGC) and intestinal-type gastric cancer were assessed using multivariate logistic regression analyses adjusted for age and sex. Allelic differences in the contribution to gene expression were measured using luciferase assays.

RESULTS

SNP c.1162+162C>T (rs2227692) in intron 7 was associated with susceptibility to DGC but not with susceptibility to intestinal-type gastric cancer. The minor allele-carrying genotypes C/T and T/T had 1.6-fold greater odds of DGC than the C/C genotype (P = .00084). This SNP was linked to a repeat-number variation c.1162+604AAAG(11_17), a deletion (del) variation c.1162+664_1162+673del, and another SNP c.1162+859T>A (rs2070683) in intron 7 based on the sequencing of 5 patients and 5 controls. The risk haplotype of the 4 variations exhibited a 30% greater gene expression level than the nonrisk haplotype in luciferase reporter assays (P = .025). In contrast, DGC susceptibility was not associated with the c.-1969_-1968insG polymorphism (rs1799768) in the promoter, commonly known as 4G/5G, in which the minor 5G allele is less active in transcription than the major 4G allele.

CONCLUSIONS

An association between SERPINE1 and DGC susceptibility was observed with 4 correlated polymorphisms in intron 7 rather than the 4G/5G polymorphism in the promoter, although all polymorphisms affected gene expression.

Association of polymorphisms in the genes of the urokinase plasminogen activation system with susceptibility to and severity of non-small cell lung cancer

BACKGROUND

Urokinase plasminogen activating (uPA) system is implicated in neoplastic progression. High tissue levels of uPA system components correlate with a poor prognosis in lung cancer. The present study examined the single nucleotide polymorphisms (SNPs) of uPA and the corresponding receptor, uPAR, for exploring their roles in non-small cell lung cancer (NSCLC).

METHODS

The allele frequencies and genotype distributions of uPA rs4065 C/T and uPAR rs344781 (-516 T/C) among 375 NSCLC cases and 380 healthy controls were examined using polymerase chain reaction-restriction fragment-length polymorphism (PCR-RFLP) analysis. Putative association between the above SNPs and clinicopathological characteristics of NSCLC were also analyzed.

RESULTS

The genotype frequencies of the variant homozygotes of uPA and uPAR were significantly different between NSCLC and control subjects. Significant association was also observed between the examined genotypes and disease stage of NSCLC. Logistic regression analysis revealed that individuals with uPA rs4065 TT genotype have higher odds ratios (ORs) for lung cancer. Whereas, subjects with uPAR-344781 CC genotype have lower ORs for lung cancer. The patients carrying a homozygous TT genotype at uPA rs4065, or at least a T allele at uPAR-344781 (-516), had a tendency to develop advanced disease.

CONCLUSIONS

Our results revealed that genetic polymorphisms of the uPA rs4065 C/T and uPAR rs344781 (-516 T/C) were associated with the susceptibility and severity of NSCLC.

Plasminogen activator inhibitor variants PAI-1 A15T and PAI-2 S413C influence lung cancer prognosis

The plasminogen pathway plays an important role in the behavior of many tumors including lung cancer. Hence genetic variants encoding plasminogen activator (PLAU), plasminogen receptor (PLAUR), plasminogen activator inhibitor 1 (PAI-1) and plasminogen activator inhibitor 2 (PAI-2) may contribute to lung cancer prognosis. To investigate this proposition we genotyped PAI-1 A15T, PLAU L141P, PLAUR L317P and PAI-2 S413C variants in 698 patients with lung cancer, 522 with non-small cell (NSCLC) and 176 with small cell lung cancer (SCLC). PAI-1 A15T was significantly associated with overall survival (OS), with carriers of variant alleles having a worse prognosis (hazard ratio (HR)=1.14; 95% confidence interval [CI]: 1.03-1.26). An association was also detected between OS in NSCLC and carrier status for PAI-2 413C (HR=1.13; 95% CI: 1.01-1.24). These common genetic variants identified warrant further evaluation as promising prognostic markers of patient outcome.

The plasminogen activator inhibitor "paradox" in cancer

Proteolysis in general and specifically the plasminogen activating system regulated by urokinase (uPA) its specific receptor, the GPI membrane anchored urokinase receptor (uPAR) and the specific plasminogen activator inhibitor 1 (PAI-1) plays a major role in tumorigenesis, tumor progression, tumor invasion and metastasis formation. This is exemplified by a body of published work showing a positive correlation between the expression of uPA or uPAR in several tumors and their malignancy. It is generally assumed that such a "pro-malignant" effect of the uPA-uPAR system is mediated by increased local proteolysis thus favoring tumor invasion, by a pro-angiogenic effect of this system and also by uPA-uPAR signaling towards the tumor thereby shifting the tumor phenotype to a more "malignant" one. However, when tumor patients are analyzed for long term survival, those with high levels of the inhibitor of the system, PAI-1 have a much worse prognosis than those with lower PAI-1 levels. This indicates that increased overall proteolysis alone cannot be made responsible for the adverse effects of the plasminogen activating system in tumors. Moreover, it becomes increasingly evident that components of the fibrinolytic system secreted by the tumor cells themselves are not solely responsible for a correlation between the plasminogen activating system and tumor malignancy; components of the plasminogen activating system secreted by stroma cells or cells of the immune system such as macrophages contribute also to the impact of fibrinolysis on malignancy. This review summarizes the evidence for the role of plasminogen activator inhibitor-1 in mediating the malignant phenotype and possible mechanism thereby trying to explain the "PAI-1 paradox in cancer" on a molecular level.