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Ari Ristimäki

Publications and source records attributed to Ari Ristimäki.

At least 19 recordsLinked to original sources
PubMed2007

Chlorpromazine and apigenin reduce adenovirus replication and decrease replication associated toxicity.

BACKGROUND: Adenoviruses can cause severe toxicity in immunocompromised individuals. Although clinical trials have confirmed the potency and safety of selectively oncolytic adenoviruses for treatment of advanced cancers, increasingly effective agents could result in more toxicity and therefore it would be useful if replication could be abrogated if necessary. METHODS: We analyzed the effect of chlorpromazine, an inhibitor of clathrin-dependent endocytosis and apigenin, a cell cycle regulator, on adenovirus replication and toxicity. First, we evaluated the in vitro replication of a tumor targeted Rb-p16 pathway selective oncolytic adenovirus (Ad5/3-Delta24) and a wild-type adenovirus in normal cells, fresh liver samples and in ovarian cancer cell lines. Further, we analyzed the in vitro cell killing efficacy of adenoviruses in the presence and absence of the substances. Moreover, the effect on in vivo efficacy, replication and liver toxicity of the adenoviruses was evaluated. RESULTS: We demonstrate in vitro and in vivo reduction of adenovirus replication and associated toxicity with chlorpromazine and apigenin. Effective doses were well within what would be predicted safe in humans. CONCLUSIONS: Chlorpromazine and apigenin might reduce the replication of adenovirus, which could provide a safety switch in case replication-associated side effects are encountered in patients. In addition, these substances could be useful for the treatment of systemic adenoviral infections in immunosuppressed patients.

Adenocarcinoma↗
PubMed2006

Prognostic significance of cyclin A in gastric cancer.

High level of cyclin A promotes carcinogenesis, and overexpression of cyclin A has been associated with poor prognosis of cancer patients. We validated the prognostic role of cyclin A in gastric cancer and evaluated its correlation with expression of an mRNA stability factor HuR. From 342 consecutive histologically confirmed gastric cancer patients were obtained 325 representative tissue specimens for cyclin A and 316 for HuR immunohistochemistry. Specimens were stained by cyclin A and HuR specific monoclonal antibodies. Nuclear immunostaining detected in > or =5% of the tumor cells was considered the cut-off for cyclin A positivity. Positive HuR immunoreactivity was scored as nuclear or cytoplasmic. Associations between scores, clinicopathological factors and survival were calculated by the chi2-test, Fisher's exact test, Kaplan-Meier test and Cox model. Cyclin A detected in the nuclei of cancer cells was positive in 55% (179 of 325) of the specimens; 40% (127 of 316) of the specimens had cytoplasmic and 88% (279 of 316) nuclear immunoreactivity of HuR. Cyclin A expression was an independent prognostic factor for poor survival. Cyclin A immunoreactivity was associated with old age, high stage, proximal location of the tumor, intestinal type, noncurative resection, advanced penetration depth and with nodal metastases but not distant metastases. Furthermore, cyclin A expression was associated with cytoplasmic HuR expression, whereas no association with nuclear HuR was evident. Cyclin A is an independent prognostic factor in gastric cancer, and one mechanism for its overexpression may depend on cytoplasmic localization of HuR.

Aged↗
PubMed2006

Early-onset gastric cancers have a different molecular expression profile than conventional gastric cancers.

Many studies examine the molecular genetics of gastric cancer, but few look at young patients in particular and there is no comparison of molecular expression between early-onset gastric cancer (< or = 45 years old) and conventional gastric cancers. Expression of cycloxygenase-2 (COX-2) is elevated in gastric adenocarcinomas compared to non-neoplastic mucosa, and in light of studies showing reduced risk of gastric cancer in nonsteroidal anti-inflammatory drug users, we have chosen to investigate the expression of COX-2 and related molecules in 113 early-onset gastric cancers and compare it with 91 conventional gastric cancers, using tissue microarrays. These markers include molecules known to be important in conventional gastric carcinogenesis, such as E-Cadherin, p53, COX-2, Trefoil Factor-1 (TFF1), beta-catenin, p16 and c-myc; as well as molecules not yet described as being important in gastric cancer, such as the transcription factor c-jun, the COX-2 mRNA stabilizer HuR, and C/EBP-beta, a transcription factor for COX-2. All markers showed a statistically significant difference between early-onset gastric cancers and conventional gastric cancers, using a chi2 test. In particular, early-onset gastric cancers displayed a COX-2 Low, TFF1-expressing phenotype, whereas COX-2 overexpression and loss of TFF1 was found in conventional cancers, and this difference between early-onset gastric cancers and conventional cancers remained statistically significant when adjusted for location and histology (P<0.0001 and P = 0.002 respectively). We found that COX-2 overexpression correlates significantly with loss of TFF1 (P = 0.001), overexpression of C/EBP-beta (P<0.001) and cytoplasmic HuR (P = 0.016). COX-2 was significantly associated with p53 positivity (P = 0.003). Abnormalities in E-Cadherin correlated significantly with diffuse phenotype, whereas high expression of COX-2, loss of TFF1 and overexpression of C/EBP-beta correlated with the intestinal phenotype. Our results provide further evidence that early-onset gastric cancer exhibits a distinctive expression profile that may have practical implications.

Adult↗
PubMed2006

VEGF-C and COX-2 expression in papillary thyroid cancer.

In papillary thyroid cancer (PTC), age appears to be the most important single prognostic factor. Another characteristic feature is the lack of association between survival and lymph node metastases. Earlier, we found that expression of cyclooxygenase-2 (COX-2) is higher in older PTC patients, in agreement with the finding that older patients have a worse prognosis. Recent findings suggest that COX-2 can up-regulate vascular endothelial growth factor-C (VEGF-C) expression. Here, we investigated whether expression of VEGF-C differs between young and older PTC patients and whether expression of VEGF-C and COX-2 are correlated. Our retrospective study comprised 106 PTC patients selected by age: those under 35 or over 55 at diagnosis. Paraffin-embedded tissue samples were analysed by immunohistochemistry for VEGF-C protein expression. Furthermore, we investigated by quantitative RT-PCR and enzyme immunoassay the relationship between VEGF-C and COX-2 expression in papillary thyroid cancer cells (NPA cells). VEGF-C expression was significantly increased with age. In the tumours from older lymph node-positive (N1) patients, VEGF-C expression was significantly higher than in the tumours from young N1 patients. Moreover, all patients who died of cancer or who developed distant metastases were old, and most tumours from these patients (4 of 5) expressed VEGF-C and had had nodal metastases at the time of primary operation. Immunohistochemically, expression of COX-2 and VEGF-C correlated strongly. In cell culture, this correlation was not so clear, because the COX-2 selective inhibitor, NS-398, did not reduce VEGF-C expression. However, as both COX-2 and VEGF-C were induced by the tumour promoter phorbol 12-myristate 13-acetate (PMA), the same factors may control them both.

Adult↗
PubMed2006

Cyclooxygenase-2 expression in squamous cell carcinoma of the oral cavity and pharynx: association to p53 and clinical outcome.

Cyclooxygenase-2 (COX-2) expression is up-regulated in transformed cells and in malignant tissues, including tumours of the head and neck, and it has prognostic significance in many types of cancer. COX-2 expression is suppressed by the wild-type but not by the mutant tumour suppressor gene TP53. The purpose of this study was to investigate the association between the expression of COX-2 and the clinical outcome in patients with oral and pharyngeal squamous cell carcinoma (SCC), and to examine its relationship to p53. Immunohistochemistry showed an elevated COX-2 expression in 88% (n = 57; strong 38, weak 19) of the 65 tumour samples. The staining intensity was not associated with patient or tumour characteristics, nor with the immuhistochemical expression of p53. Kaplan-Meier analysis showed no significant correlation between COX-2 expression and recurrence-free or overall survival, but a strong p53 expression was associated with a poor recurrence-free (p = 0.001, log-rank) and overall survival (p = 0.003). We conclude that, unlike strong p53 expression, COX-2 expression does not have prognostic significance in advanced oral and pharyngeal SCCs.

Adult↗
PubMed2005

Expression of cyclooxygenase-2 is regulated by glycogen synthase kinase-3beta in gastric cancer cells.

Cyclooxygenase-2 (COX-2) expression is a marker of poor prognosis in gastric cancer patients, and its inhibition suppresses gastric tumorigenesis in experimental animal models. The mechanism that leads to COX-2 overexpression in this tumor type is unknown. We have now shown that inhibition of phosphatidylinositol 3-kinase by LY294002 suppresses both basal and phorbol myristate acetate-induced COX-2 expression in TMK-1 and MKN-28 gastric cancer cells. Furthermore, inhibition of glycogen synthase kinase-3beta (GSK-3beta) by SB415286 induced expression of COX-2 mRNA and protein as well as the enzyme activity in the gastric cancer cells. The effect of SB415286 was confirmed by the use of two additional GSK-3beta inhibitors, lithium chloride and SB216763. SB415286 had a modest 1.6-fold stimulatory effect on a 2-kb COX-2 promoter reporter construct, but more importantly, it was shown to block the decay of COX-2 mRNA. In contrast to modulation of phosphatidylinositol 3-kinase/Akt/GSK-3beta pathway, inhibitors of mitogen-activated protein kinases (MEK 1/2, p38, JNK) or the mammalian target of rapamycin did not alter COX-2 expression in gastric cancer cells. Our data show that inhibition of GSK-3beta stimulates COX-2 expression in gastric cancer cells, which seems to be primarily facilitated via an increase in mRNA stability and to a lesser extent through enhanced transcription.

Aminophenols↗
PubMed2005

Cyclooxygenase-2 is an independent prognostic factor in gastric cancer and its expression is regulated by the messenger RNA stability factor HuR.

PURPOSE: Cyclooxygenase-2 (COX-2) promotes carcinogenesis and its expression associates with clinicopathologic characteristics in gastric cancer. HuR is an mRNA binding protein that controls the stability of certain transcripts including COX-2. We evaluated the prognostic significance of COX-2 and HuR expressions in gastric cancer and whether there exists a link between HuR and COX-2 expressions. EXPERIMENTAL DESIGN: The study included 342 consecutive patients with histologically confirmed gastric adenocarcinoma, of whom 321 patients had tissue specimens available for COX-2 and 316 for HuR immunohistochemistry. Specimens were stained by COX-2- and HuR-specific monoclonal antibodies and scored by two independent observers. Correlation to clinical data and survival was assessed. TMK-1 gastric adenocarcinoma cells were treated with small interfering RNA against HuR and expressions of HuR and COX-2 were detected by immunofluorescence and Western blot analysis. RESULTS: Patients with low COX-2 expression had a cumulative 5-year survival of 53% and those with high COX-2 expression had 16% (P < 0.0001). In multivariate analysis, COX-2 was an independent prognostic factor (P = 0.003). Cytoplasmic HuR expression was associated with high COX-2 expression (P < 0.0001) and with reduced survival (P = 0.004) whereas nuclear positivity for HuR was not. When TMK-1 cells were treated with HuR small interfering RNA, expressions of HuR and COX-2 were reduced. CONCLUSIONS: High COX-2 is an independent prognostic factor in gastric cancer. Cytoplasmic expression of HuR associates with high COX-2 expression and with reduced survival, and tissue culture experiments show that HuR can regulate expression of COX-2 in gastric cancer cells.

Adenocarcinoma↗
PubMed2005

Prognostic role of cyclooxygenase-2 in neoadjuvant-treated patients with squamous cell carcinoma of the esophagus.

Based on our previous demonstration that elevated cyclooxygenase-2 (COX-2) expression is a prognostic factor for reduced survival in patients with adenocarcinoma of the esophagus, the aim of our study was to analyze the role of COX-2 expression in esophageal squamous cell carcinoma. We analyzed COX-2 protein expression from 117 consecutive patients by immunohistochemistry using a COX-2 specific monoclonal antibody. Eighty-one patients had not received any therapy before surgery whereas 36 patients received neoadjuvant chemotherapy as part of a randomized controlled trial. In the patients who received no chemotherapy, COX-2 expression was low in 75% and high in 25% of the specimens. In this patient group, high COX-2 expression associated with distal location of the tumor (p = 0.02), but did not correlate with any other clinicopathological parameter tested, including overall survival. In the patient group who received neoadjuvant chemotherapy, postoperative COX-2 expression was low in 69% and high in 31%. Interestingly, in this patient group low COX-2 expression correlated with development of distant metastases (p = 0.03) and to reduced overall survival (p = 0.02). Our results show that the prognostic significance of COX-2 depends on the histological type of esophageal carcinoma and preoperative treatment of the patient. In conclusion, COX-2 is not a prognostic marker in squamous cell carcinoma of the esophagus, but low COX-2 expression is associated with poor prognosis in the neoadjuvant-treated patients.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2005

Breast cancer patients with p53 Pro72 homozygous genotype have a poorer survival.

PURPOSE: The p53 R72P polymorphism has been suggested to play a role in many cancers, including breast cancer. Our aim was to evaluate association of R72P with breast cancer risk as well as histopathologic features of the breast tumors and survival. EXPERIMENTAL DESIGN: The germ line R72P genotype was defined among 939 Finnish familial and 888 unselected breast cancer patients and 736 healthy population controls. The clinical and biological variables were tested for association by univariate analysis and the effects of several variables on survival by Cox's proportional hazards regression model. RESULTS: The distribution of the genotypes was similar in all groups studied, suggesting no association with breast cancer risk. Unselected breast cancer patients with 72P homozygous genotype presented significantly more often with lobular carcinoma, whereas R72 allele carriers had a significantly higher frequency of ductal carcinomas (P = 0.004). No significant association with other histopathologic variables, like tumor grade, hormone receptor status (estrogen and progesterone receptors), or tumor-node-metastasis stage, was observed. Survival analysis showed that unselected breast cancer patients with 72P homozygous genotype had significantly poorer survival than patients with other genotypes (P = 0.003). This effect on survival was independent of p53 expression in the tumors and multivariate analysis showed that 72P homozygous genotype was overall an independent prognostic factor (risk ratio of death, 2.1; 95% confidence interval, 1.4-3.3; P = 0.001). CONCLUSIONS: These results suggest no effect of either R72P allele on breast cancer risk but a significantly reduced survival for 72P homozygous breast cancer patients. The finding of codon 72 genotype as an independent prognostic marker for breast cancer warrants further studies.

Biomarkers, Tumor↗
PubMed2005

Prognostic factors in papillary thyroid cancer: an evaluation of 601 consecutive patients.

BACKGROUND: Although papillary thyroid cancer (PTC) is among the most curable cancer types, it can be a distressing disease for those patients suffering from frequent recurrences or even distant metastases leading to death. Age over 45 years is the most important indicator of poor prognosis. Our aim was to evaluate markers which might predict the outcome of an individual patient better than does TNM classification alone. MATERIALS AND METHODS: Of 601 consecutive patients who underwent surgery for PTC, retrospectively we selected 36 patient pairs in which one recovered completely after primary surgery, and the other suffered from aggressive disease. Formalin-fixed, paraffin-embedded tumor samples from these 72 patients were analyzed by immunohistochemistry for COX-2, MMP-2, VEGF-C, Bcl-2, Ki-67, and p21 expression. RESULTS AND CONCLUSIONS: None of the markers we studied showed a superiority over TNM classification in selecting patients likely to progress to aggressive disease. However, the expression of COX-2 and VEGF-C seemed to be increased in patients over 45, which could explain the more aggressive behavior of these tumors. Moreover, we found that age over 45, tumor size over 4 cm, extrathyroidal extension of tumor, nodal metastases, distant metastases, and stage IV had an unfavorable effect on survival.

Adult↗
PubMed2005

Cytoplasmic HuR expression is a prognostic factor in invasive ductal breast carcinoma.

HuR is a ubiquitously expressed mRNA-binding protein. Intracellular localization of HuR is predominantly nuclear, but it shuttles between the nucleus and the cytoplasm. In the cytoplasm it can stabilize certain transcripts. Because nucleocytoplasmic translocation of HuR is necessary for its activity, it was hypothesized that cytoplasmic HuR expression in cancer cells could be a prognostic marker. To test the significance of HuR in carcinogenesis of the breast, we have investigated HuR expression in a mouse mammary gland tumor model and from 133 invasive ductal breast carcinoma specimens. HuR expression was elevated in the cyclooxygenase-2 transgene-induced mouse mammary tumors, and its expression was predominantly cytoplasmic in the tumor cells. In the human carcinoma samples, high cytoplasmic immunoreactivity for HuR was found in 29% (38 of 133) of the cases. Cytoplasmic HuR expression associated with high grade (P = 0.0050) and tumor size over 2 cm (P = 0.0082). Five-year distant disease-free survival rate was 42% [95% confidence interval (95% CI), 26-58] in cytoplasm-high category and 84% (95% CI, 76-91) in cytoplasm-negative or -low category (P < 0.0001), and high cytoplasmic expression of HuR was an independent prognostic factor in a Cox multivariate model (relative risk 2.07; 95% CI, 1.05-4.07). Moreover, high cytoplasmic HuR immunopositivity was significantly associated with poor outcome in the subgroup of node-negative breast cancer in a univariate analysis (P < 0.0007). Our results show that high cytoplasmic HuR expression is associated with a poor histologic differentiation, large tumor size, and poor survival in ductal breast carcinoma. Thus, HuR is the first mRNA stability protein of which expression associates with poor outcome in breast cancer.

Animals↗
PubMed2005

Association of cyclooxygenase-2 and matrix metalloproteinase-2 expression in human breast cancer.

Expression of cyclooxygenase-2 (COX-2) and matrix metalloproteinase-2 (MMP-2) associates with reduced survival in human breast cancer. COX-2 may be directly involved with mammary carcinogenesis, since expression of COX-2 is sufficient for formation of breast tumors in transgenic mice, and COX-2 selective inhibitors can suppress tumorigenesis in rodent models of breast cancer. MMP-2 is an extracellular matrix degrading proteolytic enzyme that bas been linked to invasion and metastasis. A direct link between COX-2 and MMP-2 may exist, since inhibition of COX-2 activity can result in reduction of MMP-2 expression and activity. In this study we analyzed protein expression of COX-2 and MMP-2 in tissue array specimens of 278 invasive breast cancers by immunohistochemistry. Immunopositivity of these two markers was correlated with each other and with various clinicopathological parameters including survival. We found high COX-2 expression in 30% and high MMP-2 expression in 83% of the breast cancer specimens, and there was a positive association between the expression of these two factors (p = 0.003). It was especially evident that whenever COX-2 expression was high, MMP-2 expression was almost invariably high (95%). Furthermore, high expression of either COX-2 or MMP-2 associated with decreased disease specific survival when compared with the COX-2 or MPP-2 low group (p = 0.026 and p = 0.021, respectively). Taken together, our results indicate that expression of COX-2 protein is associated with expression of MMP-2 protein in human breast cancer and that both COX-2 and MMP-2 are markers of poor prognosis in breast cancer.

Biomarkers, Tumor↗
PubMed2005

COX-2 inhibitors and genetic background reduce mammary tumorigenesis in cyclooxygenase-2 transgenic mice.

Cyclooxygenase-2 (COX-2) overexpression is a widely recognized feature of human breast cancer and inhibitors of the enzyme have antitumor effects in a subset of tumor settings. Previously, we demonstrated that direct overexpression of COX-2 under control of the mammary-specific MMTV promoter/enhancer, was itself oncogenic and lead to the induction of mammary tumors in multiparous, outbred CD1 mice. In the present study, we provide evidence that COX-2 dependent tumor progression can also be studied in FVB/N, an inbred strain widely used for analysis of breast cancer progression. In these mice, the human COX-2 transgene was strongly induced during pregnancy/lactation and mammary tumors developed after multiple pregnancies. However, crossing the COX-2 FVB/N mice with the C57BL6 strain resulted in loss of the mammary tumorigenic phenotype despite the fact that the human COX-2 gene was induced. Treatment of the COX-2 transgenic mice in the FVB/N strain with celecoxib (1600 ppm), a COX-2 selective inhibitor, resulted significant reduction in tumor size and multiplicity when compared to transgenic mice fed with control chow. SC-560 (20 ppm), a COX-1 selective inhibitor did not have significant effect on tumorigenesis. These studies suggest that FVB/N is a susceptible mouse strain well suited to the study of COX-2 mediated tumor progression and may provide a tool for the identification of interacting genes and therapeutic treatments for this clinically important target.

Animals↗
PubMed2005

Cytoplasmic HuR expression correlates with epithelial cancer cell but not with stromal cell cyclooxygenase-2 expression in mucinous ovarian carcinoma.

UNLABELLED: Cyclooxygenase-2 (COX-2) expression has been found to associate with poor prognosis in several types of carcinomas. HuR is an mRNA stability protein and it regulates the expression of COX-2. OBJECTIVES AND METHODS: We analyzed the expression of COX-2 and HuR in 64 mucinous ovarian carcinoma specimens by immunohistochemistry. RESULTS: In mucinous tumors, high COX-2 protein expression was found in epithelial cancer cells in 39% (22/56) and in stromal cells in 24% (13/55) of the specimens. The expression of COX-2 in cancer cells correlated with high grade (P = 0.0285), but stromal COX-2 expression had no correlation with any clinical parameter tested. Cytoplasmic HuR protein expression was observed in cancer cells in 47% (27/57) and in stromal cells in 7% (4/56) of the mucinous tumors, and it correlated with COX-2 expression in the cancer cells (P = 0.0162) but not in the stroma. CONCLUSION: Our results support the hypothesis that cytoplasmic HuR is connected to COX-2 expression in ovarian carcinoma, but that its role is restricted to the transformed epithelial cancer cells.

Adenocarcinoma, Mucinous↗
PubMed2005

Cyclooxygenase-2 expression in primary Merkel cell carcinoma.

BACKGROUND: Merkel cell carcinoma (MCC) is a highly malignant neuroendocrine skin tumor. The typical course of MCC is rapid progression of the primary tumor and metastatic dissemination to the regional lymph nodes. Thus far, no biological, prognostic marker has been established for this aggressive neoplasm. Cyclooxygenase-2 (Cox-2) is undetectable in most normal tissues, but it is induced in various cell types by inflammation and carcinogenesis. Although the expression and function of Cox-2 have been studied extensively in several carcinomas, little is known about Cox-2 expression in neuroendocrine carcinomas. The aim of the present report was to study Cox-2 expression in MCC and find out whether this expression correlates with outcome. METHODS: Immunohistochemical analysis for Cox-2 was performed on 22 primary MCC samples. RESULTS: Almost 70% of the samples showed positive staining. Protein expression of Cox-2 was sparse and low in intensity. We found a tendency for enhanced Cox-2 expression in tumors located in sun-exposed areas. Cox-2 expression had no significant statistical correlation with clinical parameters. CONCLUSIONS: MCC expresses Cox-2 in low levels, and the expression did not prove to be a prognostic factor. Furthermore, the low expression suggests that the primary treatment option for MCC is not therapeutic inhibition of Cox-2.

Aged↗
PubMed2004

Elevated cyclooxygenase-2 expression is associated with altered expression of p53 and SMAD4, amplification of HER-2/neu, and poor outcome in serous ovarian carcinoma.

PURPOSE AND EXPERIMENTAL DESIGN: Cyclooxygenase-2 (COX-2) is frequently expressed in human adenocarcinomas and inhibition of COX-2 suppresses tumor formation in various animal models of carcinogenesis. We analyzed expression of COX-2 protein in human serous ovarian carcinomas by immunohistochemistry (n = 442) and by Western blotting (n = 12) and COX-2 mRNA by reverse transcriptase PCR (n = 12). COX-2 immunoreactivity was correlated to clinicopathological variables and to expression of p53 and SMAD4 as detected by immunohistochemistry and to amplification of HER-2/neu as detected by in situ hybridization. RESULTS: COX-2 mRNA expression was detected in 75% (9 of 12) and COX-2 protein in 42% (5 of 12) of the serous ovarian adenocarcinoma specimens as detected by reverse transcriptase-PCR and Western blot analysis, respectively. Moderate to strong (elevated) immunoreactivity for COX-2 was detected in 70% (310 of 442) of the tumors. Elevated COX-2 expression associated with reduced disease-specific survival (P = 0.0011), high histological grade (P < 0.0001), residual tumor size > 1 cm (P = 0.0111), and age > 57 years (P = 0.0099). Tumors with altered immunostaining pattern for p53 or SMAD4 expressed more frequently elevated levels of COX-2 when compared with the tumors with normal staining pattern of these tumor suppressor genes (P < 0.0001 and P = 0.0004, respectively). In addition, elevated COX-2 expression associated with amplification of HER-2/neu oncogene (P = 0.0479). CONCLUSIONS: Our results suggest that elevated expression of COX-2 associates with reduced survival in serous ovarian carcinomas and that expression of COX-2 may be induced in these tumors by loss of tumor suppressor genes such as p53 and SMAD4 and by amplification of HER-2/neuoncogene.

Adolescent↗
PubMed2004

Cyclooxygenase 2: from inflammation to carcinogenesis.

Cyclooxygenase (COX) is the rate-limiting enzyme in the conversion of arachidonic acid to prostanoids. Two COX isoforms have been cloned, of which COX-1 is constitutively expressed, while the expression of COX-2 is low or nondetectable in most tissues, but can be readily induced in response to cell activation by cytokines, growth factors and tumour promoters. Thus, COX-1 is considered a housekeeping gene and thought to be responsible for the synthesis of prostanoids involved in cytoprotection of the stomach and for the production of the pro-aggregatory prostanoid thromboxane by the platelets. In contrast, COX-2 is an inducible, immediate-early gene, and its role has been related to inflammation, reproduction and carcinogenesis. Expression of COX-2 is elevated in a variety of human malignancies and in their precursor lesions. Furthermore, genetic deletion or pharmacological inhibition of COX-2 suppresses tumour growth in several animal models of carcinogenesis. In humans, elevated COX-2 expression is associated with poor prognosis in adenocarcinomas of the digestive tract and the breast, and a selective inhibitor of COX-2 reduced polyp burden in patients who suffer from familial adenomatous polyposis. Thus, COX-2 seems to be a relevant target in chemoprevention.

Animals↗