Thymidilate synthase and p53 primary tumour expression as predictive factors for advanced colorectal cancer patients

Rewiring glucose metabolism improves 5-FU efficacy in p53-deficient/KRASG12D glycolytic colorectal tumors

Despite the fact that 5-fluorouracil (5-FU) is the backbone for chemotherapy in colorectal cancer (CRC), the response rates in patients is limited to 50%. The mechanisms underlying 5-FU toxicity are debated, limiting the development of strategies to improve its efficacy. How fundamental aspects of cancer, such as driver mutations and phenotypic heterogeneity, relate to the 5-FU response remains obscure. This largely relies on the limited number of studies performed in pre-clinical models able to recapitulate the key features of CRC. Here, we analyzed the 5-FU response in patient-derived organoids that reproduce the different stages of CRC. We find that 5-FU induces pyrimidine imbalance, which leads to DNA damage and cell death in the actively proliferating cancer cells deficient in p53. Importantly, p53-deficiency leads to cell death due to impaired cell cycle arrest. Moreover, we find that targeting the Warburg effect in KRAS^G12D glycolytic tumor organoids enhances 5-FU toxicity by further altering the nucleotide pool and, importantly, without affecting non-transformed WT cells. Thus, p53 emerges as an important factor in determining the 5-FU response, and targeting cancer metabolism in combination with replication stress-inducing chemotherapies emerges as a promising strategy for CRC treatment.

In p53-deficient colorectal cancer organoids, 5-fluorouracil induces pyrimidine imbalance, which causes DNA damage and cell death. Rewiring glucose metabolism through PDK inhibition by DCA enhances 5-FU toxicity in glycolytic p53-deficient organoids.

Determination of thymidine phosphorylase expression level facilitates recurrence risk stratification in stage II/III colorectal cancer following adjuvant chemotherapy with oral fluoropyrimidines

The present study aimed to prospectively clarify the prognostic effect of the expression of several genes that are known to modulate 5-fluorouracil effects in 63 patients who underwent curative resection for stage II/III colorectal cancer following adjuvant chemotherapy with oral fluoropyrimidines between 2008 and 2012. Thymidine phosphorylase (TP) expression in primary tumours was significantly lower in the recurrence group compared with the no-recurrence group (P=0.03), whereas, expression levels of genes that encoded thymidylate synthase, dihydropyrimidine dehydrogenase, folylpolyglutamate synthase, γ-glutamyl hydrolase and dihydrofolate reductase were not statistically different in tumours from the recurrence and no-recurrence groups. In the multivariate analysis using stepwise Cox proportional hazards regression, the following factors were significantly associated with shorter relapse-free survival following adjuvant chemotherapy with oral fluoropyrimidines: Venous invasion [present; hazard ratio (HR)=6.51; 95% confidence interval (CI): 1.55-27.4; P=0.01), Tumour-Node-Metastasis stage (3b; HR=6.18; 95% CI: 1.36-28.2; P=0.02) and TP expression (low; HR=9.61; 95% CI: 1.81-51.0; P=0.04). Patients with two or more risk characteristics had significantly shorter 5-year relapse-free survival compared with patients with one or no risk characteristics (55.8 vs. 91.8%; log-rank P=0.0006). We concluded that low TP expression is an independent predictive factor for poor prognosis in colorectal cancer. Therefore, determining TP expression may help to improve recurrence risk stratification in patients with stage II/III colorectal cancer following adjuvant chemotherapy with oral fluoropyrimidines.

Radiotherapy and Oral Capecitabine in the Preoperative Treatment of Patients with Rectal Cancer: Rationale, Preliminary Results and Perspectives

Preoperative radiotherapy alone or combined with chemotherapy increases the chances of tumor downstaging and down-sizing and facilitates sphincter-sparing surgical procedures, thereby improving survival and quality of life. Though several innovative agents are being investigated in combination with radiotherapy, 5-fluorouracil in continuous infusion remains the common schedule used in the preoperative chemoradiation setting. However, the protracted venous infusion of 5-fluorouracil requires specialized pumps and long-term venous access, which makes patients susceptible to infections or thrombosis. To overcome the 5-fluorouracil infusion-related problems, oral 5-fluorouracil precursors and inhibitors of 5-fluorouracil degradation have been developed and explored. These include oral fluoropyrimidines such as tegafur (ftora-fur), uracil plus tegafur (UFT), S-1, eniluracil and the oral carbamate capecitabine. Phase I trials have demonstrated the feasibility of the capecitabine-radiotherapy combination with respect to the bolus or infusion 5-fluorouracil-radiation approach and have defined the optimal dose of capecitabine during radiotherapy (825 mg/m2/day through a bid administration). Severe hand-foot syndrome occurred in 7-15% of patients, representing the most commonly observed toxicity. It is noteworthy that severe diarrhea with capecitabine during radiotherapy was not common. Leukopenia frequently occurred but was mild and reversible. Phase II trials, although limited in number, have evidenced a high probability of pathological complete response (up to 31%) with capecitabine and radiation, with an increased probability of sphincter-sparing surgical procedures. Although it is too early to assess whether oral capecitabine will be able to replace iv 5-fluorouracil in combination with preoperative radiotherapy, the NSABP will address this question in a large randomized trial. Finally, phase I-II trials evaluating escalating doses of capecitabine associated with oxaliplatin or irinotecan with radiotherapy are being carried out to assess the maximum-dose tolerance and efficacy in the preoperative setting. It is likely that these new chemoradiation associations might increase rectal cancer clearance, hopefully without increasing toxicity.

Resistance to cancer chemotherapeutic drugs is determined by pivotal microRNA regulators

Chemo-resistance, which is the main obstacle in cancer therapy, is caused by the onset of drug-resistant cells in the heterogeneous cell population in cancer tissues. MicroRNAs regulate gene expression at the post-transcriptional level, and they are involved in many different biological processes, including cell proliferation, differentiation, metabolism, stress response, and apoptosis. The aberrant expression of microRNAs plays a major pathogenic role from the early stages of the carcinogenesis process. Recently, microRNAs have been reported to play an important role in inducing resistance to anti-cancer drugs. Specific microRNA alterations occur selectively in cancer cells, rendering these cells resistant to various chemotherapeutic agents. For example, resistance to 5-fluorouracil is mediated by alterations in miR-21, miR-27a/b, and miR-155; the sensitivity to Docetaxel is influenced by miR-98, miR-192, miR-194, miR-200b, miR-212, and miR-424; and the resistance to Cisplatin is mediated by miR-let-7, miR-15, miR-16 miR-21 and miR-214. Chemo-resistant cancer cells are characterized by altered functions in enzymes that are involved in microRNA maturation, primarily including Dicer, as demonstrated in ovarian cancer, oral squamous cell carcinoma, breast cancer and cervical cancer. Based on the evidence reviewed in this paper, various strategies have been developed to artificially re-establish microRNA expression in resistant cells, thus restoring chemo-sensitivity. These strategies employ synthetic analogs, anti-microRNA oligonucleotides, locked nucleic acid, microRNA sponges, drugs that inhibit DNA methylation or histone deacetylation, and the introduction of microRNA mimics. The ability to modulate microRNA expression is a promising strategy for overcoming the problem of drug resistance in cancer treatment.

Evaluation of 5-fluorouracil metabolic enzymes as predictors of response to adjuvant chemotherapy outcomes in patients with stage II/III colorectal cancer: a decision-curve analysis

BACKGROUND

The effectiveness of 5-fluorouracil (5-FU)-based adjuvant chemotherapy is reported in patients with colorectal cancer (CRC), but the usefulness of 5-FU metabolic enzymes as predictive biomarkers of the efficacy of this chemotherapy remains unclear.

OBJECTIVE

This study aims to verify whether 5-FU metabolic enzymes are predictive biomarkers in the clinical setting of adjuvant chemotherapy for stage II/III CRC.

METHODS

In total, 179 patients with stage II/III CRC who were treated at our institute between 2000 and 2010 were enrolled. Messenger RNA (mRNA) expression of major 5-FU metabolic enzymes, namely thymidylate synthase, dihydropyrimidine dehydrogenase, thymidine phosphorylase (TP), orotate phosphoribosyl transferase, and β-actin (control) was evaluated using the Danenberg Tumor Profile method. mRNA expression and other clinicopathological data were investigated with regard to CRC relapse.

RESULTS

A total of 78 patients underwent surgery alone, while 101 underwent adjuvant chemotherapy (5-FU plus leucovorin [LV] or tegafur plus uracil /LV) following surgery. Relapse-free survival was longer and risk of recurrence was lower in association with high TP mRNA expression than in association with low TP mRNA expression in the adjuvant chemotherapy group (hazard ratio 0.66; 95 % confidence interval 0.47-0.92; p = 0.016), but not in the surgery alone group. mRNA expression of no other enzymes was associated with relapse in both groups. In decision-curve analyses, the predictive efficiency of TP mRNA expression plus clinicopathological factors was slightly better than that of clinicopathological factors only.

CONCLUSIONS

TP mRNA expression in tumors predicted the effects of adjuvant chemotherapy for stage II/III CRC, although the beneficial effects were marginal.

Pharmacogenetics research on chemotherapy resistance in colorectal cancer over the last 20 years

During the past two decades the first sequencing of the human genome was performed showing its high degree of inter-individual differentiation, as a result of large international research projects (Human Genome Project, the 1000 Genomes Project International HapMap Project, and Programs for Genomic Applications NHLBI-PGA). This period was also a time of intensive development of molecular biology techniques and enormous knowledge growth in the biology of cancer. For clinical use in the treatment of patients with colorectal cancer (CRC), in addition to fluoropyrimidines, another two new cytostatic drugs were allowed: irinotecan and oxaliplatin. Intensive research into new treatment regimens and a new generation of drugs used in targeted therapy has also been conducted. The last 20 years was a time of numerous in vitro and in vivo studies on the molecular basis of drug resistance. One of the most important factors limiting the effectiveness of chemotherapy is the primary and secondary resistance of cancer cells. Understanding the genetic factors and mechanisms that contribute to the lack of or low sensitivity of tumour tissue to cytostatics is a key element in the currently developing trend of personalized medicine. Scientists hope to increase the percentage of positive treatment response in CRC patients due to practical applications of pharmacogenetics/pharmacogenomics. Over the past 20 years the clinical usability of different predictive markers has been tested among which only a few have been confirmed to have high application potential. This review is a synthetic presentation of drug resistance in the context of CRC patient chemotherapy. The multifactorial nature and volume of the issues involved do not allow the author to present a comprehensive study on this subject in one review.

Apoptosis and molecular targeting therapy in cancer

Apoptosis is the programmed cell death which maintains the healthy survival/death balance in metazoan cells. Defect in apoptosis can cause cancer or autoimmunity, while enhanced apoptosis may cause degenerative diseases. The apoptotic signals contribute into safeguarding the genomic integrity while defective apoptosis may promote carcinogenesis. The apoptotic signals are complicated and they are regulated at several levels. The signals of carcinogenesis modulate the central control points of the apoptotic pathways, including inhibitor of apoptosis (IAP) proteins and FLICE-inhibitory protein (c-FLIP). The tumor cells may use some of several molecular mechanisms to suppress apoptosis and acquire resistance to apoptotic agents, for example, by the expression of antiapoptotic proteins such as Bcl-2 or by the downregulation or mutation of proapoptotic proteins such as BAX. In this review, we provide the main regulatory molecules that govern the main basic mechanisms, extrinsic and intrinsic, of apoptosis in normal cells. We discuss how carcinogenesis could be developed via defective apoptotic pathways or their convergence. We listed some molecules which could be targeted to stimulate apoptosis in different cancers. Together, we briefly discuss the development of some promising cancer treatment strategies which target apoptotic inhibitors including Bcl-2 family proteins, IAPs, and c-FLIP for apoptosis induction.

Thymidylate synthase expression and p21(WAF1)/p53 phenotype of colon cancers identify patients who may benefit from 5-fluorouracil based therapy

Background

Studies on the expression of thymidylate synthase (TS) in colorectal cancers (CRCs) have failed to provide unequivocal prognostic or predictive information. Here, we assessed the prognostic significance of TS expression in Astler-Coller stage B2 and C CRCs defined by a p21^WAF1/p53 immunophenotype in patients subjected to 5-fluorouracil (5FU)-based adjuvant therapy.

Methods

A cohort of 189 CRCs was asssessed for TS, p21^WAF1 and p53 expression on tissue microarrays using immunohistochemistry, and associations with disease-free survival (DFS) and overall survival (OS) of the patients were assessed using univariate and multivariate analyses.

Results

TS expression led to the stratification of patients with colon cancer, but not rectal cancer, with immunophenotypes other than p21^WAF1+/p53- (referred to as P&P) into subgroups characterized by a worse (P&P TS+) and a better (P&P TS-) DFS and OS, in univariate (P = 0.006 and P = 0.005, respectively) and multivariate (P = 0.0004 and P = 0.002, respectively) analyses. The p21^WAF1+/p53- immunophenotype was associated with a favorable prognosis, irrespective of TS expression.

Conclusions

The strong association observed between the P&P TS+ immunophenotype and a worse DFS and OS suggests a predictive significance of TS expression for 5FU-based adjuvant therapy in patients with colon cancers exhibiting the P&P immunophenotype. In addition, our findings suggest that the appropriate target for assessment of TS expression as a prognostic/predictive marker is a subgroup of colon cancers with an immunophenotype other than p21^WAF1+/p53-, and that only in this subgroup high TS expression is associated with an unfavorable DFS and OS. Therefore, we suggest that assessing TS expression in conjunction with p21^WAF1/p53 immunophenotyping of colon cancers may improve the selection of patients suitable for 5FU-based adjuvant chemotherapy.

Thymidylate synthase gene polymorphism and survival of colorectal cancer patients receiving adjuvant 5-fluorouracil

Limited studies indicate a possible association of 5'-UTR thymidylate synthase enhancer region polymorphism and treatment outcome in patients medicated with 5-fluorouracil (5-FU). The study was designed to verify the relationship in patients with colorectal cancer (CRC), a Polish population that received 5-FU-based adjuvant chemotherapy. The study analyzed 145 Astler-Coller B2 and C CRC patients. Genotyping for a variable number of tandem repeats and G to C single-nucleotide polymorphism in the 5'-UTR of the thymidylate synthase (TS) gene was carried out. TS genotypes were classified into high expression (high TS) and low expression types (low TS). High TS was found in 22.8% of patients. The right-side tumors were more frequently associated with high TS than the left-side tumors (p=0.024). High TS was only found in 9.3% of rectal tumors, but in 29.7% of colon cancers (p=0.0042). Disease-free survival after 20 months (DFS 20) was longer in subjects with low TS than in high TS (p=0.043). Patients who underwent chemotherapy had longer DFS 20 in the low TS than in the high TS subgroup (p=0.051). The low TS was found to be an independent good prognostic factor for DFS 20 in the whole group as well as in the subgroup treated with chemotherapy (p=0.024 and p=0.034, respectively). Patients with low TS did not show any differences in DFS 20 whether they were treated with adjuvant chemotherapy or not. Proximal CRC tumors are characterized by higher TS expression genotypes than distal tumors, and are at significantly greater risk of early recurrence during the first 20 months after surgery.

Factors predicting the response to oral fluoropyrimidine drugs: a phase II trial on the individualization of postoperative adjuvant chemotherapy using oral fluorinated pyrimidines in stage III colorectal cancer treated by curative resection (ACT-01 Study)

We evaluated the predictive relevance of several biomarkers on the survival of patients with stage III colorectal cancer treated with adjuvant chemotherapy of oral fluoropyrimidines. This was a multicenter phase II trial on adult patients with histologically confirmed resected stage III (Dukes' C) colorectal cancer. Patients received oral doxifluridine (800 mg/m2/day) in 3 divided doses, or oral uracil/tegafur (UFT) (400 mg/m2/day) in 2 divided doses for 5 days, every 7 days for 12 months with a 5-year follow-up. Outcome measures were disease-free survival and tissue markers [thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD) protein levels and TP, DPD, thymidylate synthase (TS) and orotate phosphoribosyltransferase (OPRT) mRNA levels in tumor samples and TS tandem-repeat type in blood samples]. There was a significant association between the intratumoral TP/DPD enzyme ratio and disease-free survival when the model included the drug, the parameter and the interactions between them [hazard ratio (HR)=2.76; P=0.00469]. The 5-year disease-free survival rate was statistically significantly higher in patients with high TP/DPD ratios [median ≥2.63: 71.9%; 95% confidence interval (CI) 61.4-80.0] compared to patients with low TP/DPD ratios (<2.63: 57.0%; 95% CI 46.3-66.3) (log-rank P=0.0277) following adjuvant therapy with oral fluoropyrimidines. No significant association was observed between the intratumoral TP/DPD enzyme ratio (cut-off value 2.0) and the disease-free survival rate in the doxifluridine group; primary endpoint (log-rank P=0.6850). The magnitude of the intratumoral TP/DPD enzyme ratio may be a potential indicator for the individualization of postoperative adjuvant chemotherapy with oral fluoropyrimidines for stage III colorectal cancer.

Association of right-sided tumors with high thymidine phosphorylase gene expression levels and the response to oral uracil and tegafur/leucovorin chemotherapy among patients with colorectal cancer

PURPOSE

To identify useful predictive factors for the response to 5-fluorouracil (5-FU)/leucovorin (LV) and oral uracil and tegafur (UFT)/LV chemotherapy among patients with colorectal cancer, we investigated the association between the gene expression levels of pyrimidine and folate metabolism-related enzymes in colorectal cancer (CRC) tissues and the response to UFT/LV neoadjuvant chemotherapy.

METHODS

The subjects were 76 CRC patients who were scheduled to undergo surgery. UFT (300 mg/m(2)/day) and LV (75 mg/body/day) were administered for 2 weeks before surgery. Biopsy samples were endoscopically obtained before drug administration. The gene expression levels of 14 genes in the biopsy samples were quantitatively evaluated using a real-time polymerase chain reaction (RT-PCR) assay.

RESULTS

Fifteen patients (19.7 %) with marked pathological regression were judged to be responders. Thymidine phosphorylase (TP) gene expression levels among the responders were significantly higher than those among the non-responders. Right-sided tumors with high TP gene expression levels were associated with a significantly higher response rate to UFT/LV chemotherapy than left-sided tumors.

CONCLUSIONS

TP gene expression levels in primary CRC tissues and the primary tumor site may be useful predictors of the efficacy of oral UFT/LV chemotherapy.

Expression and prognostic significance of thymidylate synthase (TS) in pancreatic head and periampullary cancer

BACKGROUND

Pancreatic cancer has a dismal prognosis. Attempts have been made to improve outcome by several 5-FU based adjuvant treatment regimens. However, the results are conflicting. There seems to be a continental divide with respect to the use of 5-FU based chemoradiotherapy (CRT). Furthermore, evidence has been presented showing a different response of pancreatic head and periampullary cancer to 5-FU based CRT. Expression of thymidylate synthase (TS) has been associated with improved outcome following 5-FU based adjuvant treatment in gastrointestinal cancer. This prompted us to determine the differential expression and prognostic value of TS in pancreatic head and periampullary cancer.

PATIENTS AND METHODS

TS protein expression was studied by immunohistochemistry on original paraffin embedded tissue from 212 patients following microscopic radical resection (R0) of pancreatic head (n = 98) or periampullary cancer (n = 114). Expression was investigated for associations with recurrence free (RFS), cancer specific (CSS) and overall survival (OS), and conventional prognostic factors.

RESULTS

High cytosolic TS expression was present in 26% of pancreatic head tumours and 37% of periampullary tumours (p = .11). Furthermore, TS was an independent factor predicting favourable outcome following curative resection of pancreatic head cancer (p = .003, .001 and .001 for RFS, CSS and OS, respectively). In contrast, in periampullary cancer, TS was not associated with outcome (all p > .10).

CONCLUSION

TS, was found to be poorly expressed in both pancreatic head and periampullary cancer and identified as an independent prognostic factor following curative resection of pancreatic head cancer.

Thymidylate synthase mRNA levels in plasma and tumor as potential predictive biomarkers for raltitrexed sensitivity in gastric cancer

Different chemotherapeutic agents currently available are effective only in certain subsets of patients. Predictive biomarkers will be helpful in choosing those agents and can improve the clinical efficiency by a more personalized chemotherapeutic approach. Raltitrexed is a novel water-soluble quinazoline folate analogue and can improve the efficiency of gastric cancer treatment, but its predictive biomarker remains unclear. The aim of our study was to investigate the role of plasma and tumor thymidylate synthase (TS) mRNA levels as predictive biomarkers for raltitrexed in gastric cancer. In total, 125 freshly removed gastric tumor specimens and corresponding blood samples before surgery were collected. Raltitrexed sensitivity was determined by histoculture drug response assay procedures. TS mRNA levels in tumor and plasma were determined by quantitative reverse transcription polymerase chain reaction. Plasma TS mRNA level in cancer patients was significantly higher than in healthy subjects (p = 0.009) and was significantly correlated with TS mRNA level in tumor tissues (r = 0.665, p < 0.001). Tumor and plasma TS mRNA expression levels were significantly lower in raltitrexed-sensitive group than in resistant group (p = 0.007 and 0.013, respectively). The sensitivity and accuracy of raltitrexed sensitivity prediction based on plasma TS mRNA levels were 82 and 60%, respectively, whereas the prediction based on tumor TS mRNA reached 70% sensitivity and 68% accuracy. These results indicate that TS mRNA level in plasma can mirror tumor TS mRNA level, and both of them can be used to predict raltitrexed sensitivity in gastric cancer.

Occult breast cancer presenting as metastatic adenocarcinoma of unknown primary: clinical presentation, immunohistochemistry, and molecular analysis

We report a rare presentation of a 66-year-old female with diffuse metastatic adenocarcinoma of unknown primary involving liver, lymphatic system and bone metastases. The neoplastic cells were positive for CK7 and OC125, while negative for CK20, thyroid transcription factor 1, CDX2, BRST-2, chromogranin, synaptophysin, estrogen receptor (ER), progesterone receptor (PR), and human epidermal growth factor receptor 2 (HER2/neu). Fluorescence in situ hybridization showed no amplification of the HER2/neu gene. Molecular profiling reported a breast cancer origin with a very high confidence score of 98%. The absence of immunohistochemistry staining for ER, PR, and HER2/neu further classified her cancer as triple-negative breast cancer. Additional studies revealed high expression levels of topoisomerase (Topo) I, androgen receptor, and ribonucleoside-diphosphate reductase large subunit; the results were negative for thymidylate synthase, Topo II-a and O6-methylguanine-DNA methyltransferase. The patient was initially treated with a combination regimen of cisplatin and etoposide, and she experienced a rapid resolution of cancer-related symptoms. Unfortunately, her therapy was complicated by a cerebrovascular accident (CVA), which was thought to be related to cisplatin and high serum mucin. After recovery from the CVA, the patient was successfully treated with second-line chemotherapy based on her tumor expression profile. We highlight the role of molecular profiling in the diagnosis and management of this patient and the implication of personalized chemotherapy in this challenging disease.

Predictive biomarkers with potential of converting conventional chemotherapy to targeted therapy in patients with metastatic colorectal cancer

The availability of systemic chemotherapy regimens for the treatment of patients with metastatic colorectal cancer (mCRC) is based on the results from large prospective, randomized studies. The main chemotherapeutic drugs used in treatment of mCRC are the fluoropyrimidines (5-fluorouracil (5-FU); capecitabine) in combination with either oxaliplatin (FOLFOX) or irinotecan (FOLFIRI). The objective response rate to either combination is approximately 50%, where no significant differences with regard to progression free survival or overall survival have been observed. Interestingly, a number of preclinical and clinical studies have indicated lack of full cross resistance between oxaliplatin based and irinotecan based treatment. Therefore, it is possible that certain mCRC patient subpopulations would benefit more from one drug combination rather than the other. To address this clinical problem there has been much focus on development and validation of predictive biomarkers for these three drugs. Here, we present a thorough review on the current status of predictive biomarkers for 5-FU, oxaliplatin and irinotecan treatment of mCRC patients. The overall conclusions were as follows: Several promising biomarker candidates were identified, notably thymidylate synthase for 5-FU, topoisomerase I for irinotecan and ERCC1 for oxaliplatin. However, these candidates warrant further analysis, where assay performance and clinical trial design should be in focus.

Teratoma with malignant transformation: a case report with pathological, cytogenetic, and immunohistochemistry analysis

Background. Teratoma with malignant transformation (TMT) is rare and most commonly encountered in adult patient with germ cell tumor (GCT). Method. We report a rare case of testicular teratoma with metastatic TMT/embryonal rhabdomyosarcoma (ERMS). A 44-year-old man underwent right orchiectomy which revealed a malignant teratoma, he subsequently had right pneumonectomy with two pulmonary masses containing a high-grade embryonal rhabdomyosarcoma. The patient developed liver metastasis three months after initial diagnosis. He was treated with a chemotherapy regimen with vincristine, dactinomycin, and cyclophosphamide (VAC) alternating with vincristine and irinotecan (VI) with complete resolution of his liver lesion. The tumors were examined with a battery of cytogenetic, immunohistochemical, and molecular assays. Results. The malignant cells were immunohistochemically positive for desmin, myogenin, and MyoD1. Molecular cytogenetics of embryonal rhabdomyosarcoma tissue revealed the presence of i(12p). The tumor expressed high level of TOPO2A, TOPO1, MRP1, MGMT, BCRP, ERCC1, RRM1, and TS. Conclusion. The activity of topoisomerase inhibitors and the potential usefulness of topoisomerase expression as biomarkers should be further tested in aprospective study.

The colorectal cancer disease-specific transcriptome may facilitate the discovery of more biologically and clinically relevant information

BACKGROUND

To date, there are no clinically reliable predictive markers of response to the current treatment regimens for advanced colorectal cancer. The aim of the current study was to compare and assess the power of transcriptional profiling using a generic microarray and a disease-specific transcriptome-based microarray. We also examined the biological and clinical relevance of the disease-specific transcriptome.

METHODS

DNA microarray profiling was carried out on isogenic sensitive and 5-FU-resistant HCT116 colorectal cancer cell lines using the Affymetrix HG-U133 Plus2.0 array and the Almac Diagnostics Colorectal cancer disease specific Research tool. In addition, DNA microarray profiling was also carried out on pre-treatment metastatic colorectal cancer biopsies using the colorectal cancer disease specific Research tool. The two microarray platforms were compared based on detection of probesets and biological information.

RESULTS

The results demonstrated that the disease-specific transcriptome-based microarray was able to out-perform the generic genomic-based microarray on a number of levels including detection of transcripts and pathway analysis. In addition, the disease-specific microarray contains a high percentage of antisense transcripts and further analysis demonstrated that a number of these exist in sense:antisense pairs. Comparison between cell line models and metastatic CRC patient biopsies further demonstrated that a number of the identified sense:antisense pairs were also detected in CRC patient biopsies, suggesting potential clinical relevance.

CONCLUSIONS

Analysis from our in vitro and clinical experiments has demonstrated that many transcripts exist in sense:antisense pairs including IGF2BP2, which may have a direct regulatory function in the context of colorectal cancer. While the functional relevance of the antisense transcripts has been established by many studies, their functional role is currently unclear; however, the numbers that have been detected by the disease-specific microarray would suggest that they may be important regulatory transcripts. This study has demonstrated the power of a disease-specific transcriptome-based approach and highlighted the potential novel biologically and clinically relevant information that is gained when using such a methodology.

A retrospective study on TS mRNA expression and prediction of the effects of adjuvant oral 5-fluorouracil in breast cancer

Nucleic acid-metabolizing enzymes, such as thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), thymidine phosphorylase (TP) and orotate phosphoribosyl transferase (OPRT), have attracted attention as candidates for response determinants of 5-fluorouracil (5-FU). Whether the expression levels of these enzymes can be adopted as valuable parameters for 5-FU sensitivity in breast cancer has yet to be elucidated. In the present study, intratumoral mRNA expression of TS, DPD, TP and OPRT were determined in formalin-fixed paraffin-embedded surgical specimens collected from 217 breast cancer patients, using the Danenberg Tumor Profile method, which combines microdissection and real-time-polymerase chain reaction. The significance of these enzymes as prognostic and 5-FU efficacy-predicting factors was evaluated. Our data showed that a low DPD expression is related to a high nuclear grade and other factors including hormone receptor-negativity. Low expression levels of TP were found in hormone receptor-negative tumors. TS and OPRT expression were not related to various clinicopathological factors, but patients with a high TS mRNA expression showed a significantly poorer prognosis in cases where 5-FU was not administered. The efficacy of 5-FU was more significant when administered for more than 6 months in the group with a high TS mRNA expression. These data suggest that TS mRNA expression in breast cancer tissue is an ideal predictor of outcomes for patients with no administration of 5-FU, and of the efficacy of 5-FU.

Correlation between thymidylate synthase gene variants, RNA and protein levels in primary colorectal adenocarcinomas

This study was designed to compare thymidylate synthase (TS) genotype, mRNA and protein levels in primary colorectal adenocarcinoma, and to examine the correlation between microsatellite instability (MSI) and TS expression. The TS genotype of 68 patients with colorectal cancer was determined by polymerase chain reaction (PCR) and restriction fragment length polymorphism analysis in peripheral blood mononuclear cells and tumour tissue. The TS mRNA levels in tumour tissue were measured by reverse-transcription PCR, and TS protein levels and MSI status were assessed using immunohistochemistry. Significantly higher mRNA and protein levels were observed in patients with the TS 3R/3R versus the 2R/2R and 2R/3R genotypes. There was no correlation between TS single nucleotide polymorphism and TS expression. Individuals homozygous for the six base-pair insertion in the 3'-untranslated region had significantly higher TS mRNA levels than heterozygous and homozygous wild type individuals. The TS mRNA and protein levels were significantly higher in microsatellite unstable tumours compared with microsatellite stable tumours. There was a significant association between the number of TS enhancer region repeats (in blood) and intratumoural TS mRNA and protein levels. A larger case series investigating the role of TS gene polymorphisms as predictors of sensitivity to 5-fluorouracil-based chemotherapy is required.

Thymidine phosphorylase expression in metastatic sites is predictive for response in patients with colorectal cancer treated with continuous oral capecitabine and biweekly oxaliplatin

The primary objective of this study was to determine the activity and safety profile of biweekly oxaliplatin combined with continuous oral capecitabine in the first-line treatment of metastatic colorectal cancer. A secondary endpoint was to investigate the correlation between thymidylate synthase and thymidine phosphorylase (TP) expression in metastatic tissues and tumor response. Forty-one patients received oral capecitabine 1331 mg/m every day combined with intravenous oxaliplatin 85 mg/m every 2 weeks. The overall response rate was 58.5% [95% confidence interval (CI): 43.3-73.6%], the median progression-free survival 9.4 months (95% CI: 7.7-11.2 months) and the median survival 22.3 months (95% CI: 16.1-27.5 months). There were no grade 4 toxicities, and grade 3 toxicity was also uncommon. High TP expression in metastatic tissue was significantly associated with response to treatment (P=0.019), and also with a trend towards a better median progression-free survival and overall survival compared with patients expressing low TP (P=0.056; P=0.073). This study suggests that biweekly oxaliplatin and continuous oral capecitabine is an active and well-tolerated chemotherapy regimen in the first-line treatment of metastatic colorectal cancer. Moreover, these findings add to a growing body of evidence that patients with high levels of intratumoral TP expression are the ideal candidates for capecitabine-based chemotherapy.

Gene expression and effects of orally active derivatives of fluoropyrimidine on gastric and colorectal cancer

The effects of chemotherapy on gastrointestinal cancer are influenced by the chemotherapeutic sensitivity of the cancer cells. Determining the expression of genes related to chemotherapeutic sensitivity has been used as a molecular method. The aim of the study was to clarify the relationships between the expression of genes related to chemotherapeutic sensitivity and the effects of orally active derivatives of fluoropyrimidine on gastric and colorectal cancer. Forty-five patients who underwent adjuvant chemotherapy containing orally active derivatives of fluoropyrimidine after undergoing curative surgery for gastric or colorectal cancer were enrolled. Twenty-four patients had colorectal cancer and 21 patients had gastric cancer. Total RNA was extracted from formalin-fixed, paraffin-embedded specimens of the resected tumors, and the expression of 11 genes was measured using the RT-PCR method. We then analyzed the relationships between the gene expression and the postoperative relapse rate as well as the relationships between clinicopathological factors and postoperative relapse rate. The median observation period of the subjects was 41 months. Twelve out of the 21 gastric cancer patients (57%) and 11 out of the 24 colorectal cancer patients (46%) relapsed. Although the results of a univariate analysis revealed that expression of none of the evaluated genes was related to relapse in the gastric cancer patients, excision repair cross-complementing gene 1 (ERCC1) overexpression was related to the relapse rate in colorectal cancer patients (p=0.023). When 1.295 was set as the cut-off value for ERCC1 overexpression using the receiver operating characteristic (ROC) curve, 67% of patients with ERCC1 overexpression and 25% of patients without ERCC1 overexpression relapsed. The relapse-free survival rate was lower in the group with ERCC1 overexpression than in the group without ERCC1 overexpression (p=0.046). ERCC1 overexpression appears to be a useful predictor of relapse in colorectal cancer patients receiving adjuvant therapy with regimens including orally active derivatives of fluoropyrimidine.

Development and progression of colorectal neoplasia

A variety of genetic and molecular alterations underlie the development and progression of colorectal neoplasia (CRN). Most of these cancers arise sporadically due to multiple somatic mutations and genetic instability. Genetic instability includes chromosomal instability (CIN) and microsatellite instability (MSI), which is observed in most hereditary non-polyposis colon cancers (HNPCCs) and accounts for a small proportion of sporadic CRN. Although many biomarkers have been used in the diagnosis and prediction of the clinical outcomes of CRNs, no single marker has established value. New markers and genes associated with the development and progression of CRNs are being discovered at an accelerated rate. CRN is a heterogeneous disease, especially with respect to the anatomic location of the tumor, race/ethnicity differences, and genetic and dietary interactions that influence its development and progression and act as confounders. Hence, efforts related to biomarker discovery should focus on identification of individual differences based on tumor stage, tumor anatomic location, and race/ethnicity; on the discovery of molecules (genes, mRNA transcripts, and proteins) relevant to these differences; and on development of therapeutic approaches to target these molecules in developing personalized medicine. Such strategies have the potential of reducing the personal and socio-economic burden of CRNs. Here, we systematically review molecular and other pathologic features as they relate to the development, early detection, diagnosis, prognosis, progression, and prevention of CRNs, especially colorectal cancers (CRCs).

Prognostic value of ERCC1, thymidylate synthase, and glutathione S-transferase pi for 5-FU/oxaliplatin chemotherapy in advanced colorectal cancer

BACKGROUND

The aim of this study was to determine whether the expression of the excision repair cross-complementing 1 (ERCC1), thymidylate synthase (TS) and glutathione S-transferase pi (GSTpi) predict clinical outcome in patients with advanced colorectal cancer treated with fluorouracil (5-FU)/oxaliplatin chemotherapy.

METHODS

The study population consisted of 70 patients with advanced colorectal cancer (median age, 54 years). Patients were treated with oxaliplatin 85 mg/m as a 2-hour infusion on days 1 plus leucovorin (LV) 20 mg/m over 10 minutes, followed by 5-FU bolus 400 mg/m and a 22-hour continuous infusion of 600 mg/m from day 1 to 2. Treatment was repeated at 2-week intervals. The expression of ERCC1, TS, and GSTpi in primary tumors was examined using immunohistochemistry.

RESULTS

ERCC1, TS, and GSTpi were positive in 55.7%, 68.6%, and 71.4% of cases, respectively. Patients without TS expression were more likely to respond to chemotherapy (P = 0.009). There were no significant differences between response to treatment and the ERCC1 or GSTpi expression pattern (P = 0.768, P = 0.589, respectively). The median overall survival (OS) was significantly longer in patients without ERCC1 expression (P = 0.0474). Patients who were ERCC1 positive combined with TS positive, or those with ERCC1 positive combined with TS positive and GSTpi positive had a poor OS (P = 0.0017, P = 0.0323, respectively). Multivariate analysis revealed that both ERCC1 and TS expression significantly impacted OS (hazard ratio 1.72, P = 0.023).

CONCLUSION

Immunohistochemical study of ERCC1 and TS may be useful for the prediction of clinical outcome in patients with advanced colorectal cancer treated with 5-FU and oxaliplatin.

The role of molecular markers in predicting response to therapy in patients with colorectal cancer

Advances in systemic therapy for colorectal cancer have dramatically improved prognosis. While disease stage has traditionally been the main determinant of disease course, several molecular characteristics of tumor specimens have recently been shown to have prognostic significance. Although to date no molecular characteristics have emerged as consistent predictors of response to therapy, retrospective studies have investigated the role of a variety of biomarkers, including microsatellite instability, loss of heterozygosity of 18q, type II transforming growth factor beta receptor, thymidylate synthase, epidermal growth factor receptor, and Kirsten-ras (KRAS). This paper reviews the current literature, ongoing prospective studies evaluating the role of these markers, and novel techniques such as gene profiling, which may help to uncover the more complex molecular interactions that will predict response to chemotherapy in patients with colorectal cancer.

Expression of P53, P27 and KI-67 in colorectal cancer patients of various ethnic origins: clinical and tissue microarray based analysis

BACKGROUND

This study was conducted to determine survival according to the expression of molecular markers in colorectal cancer (CRC) patients of various ethnic origins.

METHODS

Resection of primary tumor was conducted on 171 patients with CRC. Corresponding archived paraffin-embedded blocks were retrieved and tissue microarray (TMA) constructed. Immunohistochemical staining of the TMA for p53, p27 and Ki-67 was quantified by two independent pathologists. Survival was analyzed using the Kaplan-Meier product limit method.

RESULTS

With a median follow-up of 65 months, 56 patients (32.7%) died of disease. AJCC stage correlated with disease-free (DFS, P < 0.0001) and overall survival (OS, P < 0.0001). IHC staining was positive for Ki-67 in 77.4%, p53 in 55.8% and p27 in 54.2% of patients. Primary tumor marker expression did not correlate with DFS or OS. The 5-year DFS for Ashkenazi Jews was 75%, significantly higher than Sephardic Jews (SJ) 64% and Palestinian Arabs (PA) 38%, P = 0.001.

CONCLUSIONS

Ethnicity among Ashkenazi and SJ and PA appears to have a significant impact on disease outcome in patients with CRC patients, while primary tumor expression of p53, p27 and Ki-67 was unrelated to disease outcome.

Prognostic and predictive value of thymidylate synthase expression in colon cancer

Thymidylate synthase (TS) is an enzyme responsible for DNA synthesis. Its competitive inhibition constitutes the major mechanism of the antitumor effect of 5-fluorouracil (5-FU) therapy, which significantly improves the survival rate of colon cancer patients. The aim of our study was to examine the clinical importance of TS expression in colon cancer patients and to correlate its expression with various clinicopathological parameters, tumor proliferative capacity, cell cycle-related molecules' expression and patients' survival. Of the 71 colon cancer patients studied, 51 (71.8%) tested positive for TS, with the positive result being statistically significantly correlated with patients' gender (P = 0.012), tumor histological grade (P = 0.032), vascular invasion (P = 0.017) and the expression of cyclin E, pRb and p16 (P = 0.042, P = 0.001 and P = 0.001, respectively). The overall 5-year survival rate was 40% for TS-positive patients and 68.6% for TS-negative ones (P = 0.0134); in patients aged >70 years, this was 30 and 77.8%, respectively (P = 0.0008). In a multivariate analysis of survival, TS expression proved to be of prognostic significance (P = 0.0174). Our findings support evidence for the clinical importance of TS expression in colon cancer patients and define it as an independent prognostic risk factor.

The predictive value of p53 and p33(ING1b) in patients with Dukes'C colorectal cancer

OBJECTIVE

Identification of biological markers that may predict response to chemotherapy would allow the individualization of treatment by enabling selection of patients most likely to benefit from chemotherapy. The aims of this study were to determine whether p53 mutation status and p53 and p33(ING1b) protein expression can predict which patients with Dukes' C colorectal cancer following curative surgical resection respond to adjuvant chemotherapy with 5-fluorouracil (5-FU).

METHOD

Patients with Dukes'C colorectal cancer (n = 41) were studied. DNA was extracted and analysed for p53 mutation using PCR-based direct DNA sequencing. Tumours were analysed for p53 protein expression by immunohistochemistry using DO-7 monoclonal antibody and for p33(ING1b) protein expression using GN1 monoclonal antibody.

RESULTS

There was a significant association between p53 mutation status analysed by gene sequencing and overall and metastasis-free survival (P = 0.03 and 0.004, respectively, log-rank test). By contrast, no significant correlation was found between p53 and p33(ING1b) protein expression and overall or metastasis-free survival.

CONCLUSION

In patients with Dukes'C colorectal cancer who underwent curative surgical resection of the primary tumour, followed by 5-FU-based adjuvant chemotherapy, p53 mutation status as assessed by gene sequencing is a significant predictor of overall and metastasis-free survival.

Predictive value of Ki67 and p53 in locally advanced rectal cancer: Correlation with thymidylate synthase and histopathological tumor regression after neoadjuvant 5-FU-based chemoradiotherapy

AIM: To investigate the predictive value of Ki67 and p53 and their correlation with thymidylate synthase (TS) gene expression in a rectal cancer patient cohort treated according to a standardized recommended neoadjuvant treatment regimen.

METHODS: Formalin fixed, paraffin embedded pre-therapeutical tumor biopsies (n = 22) and post-therapeutical resection specimens (n = 40) from patients with rectal adenocarcinoma (clinical UICC stage II/III) receiving standardized neoadjuvant 5-fluorouracil (5-FU) based chemoradiotherapy were studied for Ki67 and p53 expression by immunohistochemistry and correlated with TS mRNA expression by quantitative TaqMan real-time PCR after laser microdissection. The results were compared with histopathological tumor regression according to a standardized semiquantitative score grading system.

RESULTS: Responders (patients with high tumor regression) showed a significantly lower Ki67 expression than non-responders in the pre-therapeutical tumor biopsies (81.2% vs 16.7%; P < 0.05) as well as in the post-therapeutical resection specimens (75.8% vs 14.3%; P < 0.01). High TS mRNA expression was significantly correlated with a high Ki67 index and low TS mRNA expression was significantly correlated with a low Ki67 index in the pre-therapeutical tumor biopsies (corr. coef. = 0.46; P < 0.01) as well as in the post-therapeutical resection specimens (corr. coef. = 0.40; P < 0.05). No significant association was found between p53 and TS mRNA expression or tumor regression.

CONCLUSION: Ki67 has, like TS, predictive value in rectal cancer patients after neoadjuvant 5-FU based chemoradiotherapy. The close correlation between Ki67 and TS indicates that TS is involved in active cell cycle processes.

Pharmacogenomics in colorectal cancer: The first step for individualized-therapy

Interindividual differences in the toxicity and response to anticancer therapies are currently observed in practically all available treatment regimens. A goal of cancer therapy is to predict patient response and toxicity to drugs in order to facilitate the individualization of patient treatment. Identification of subgroups of patients that differ in their prognosis and response to treatment could help to identify the best available drug therapy according the genetic profile. Several mechanisms have been suggested to contribute to chemo-therapeutic drug resistance: amplification or overexpression of membrane transporters, changes in cellular proteins involved in detoxification or in DNA repair, apoptosis and activation of oncogenes or tumor suppressor genes. Colorectal cancer (CRC) is regarded as intrinsically resistant to chemotherapy. Several molecular markers predictive of CRC therapy have been included during the last decade but their results in different studies complicate their application in practical clinical. The simultaneous testing of multiple markers predictive of response could help to identify more accurately the true role of these polymorphisms in CRC therapy. This review analyzes the role of genetic variants in genes involved in the action mechanisms of the drugs used at present in colorectal cancer.

Taxanes, microtubules and chemoresistant breast cancer

The taxanes, paclitaxel and docetaxel are microtubule-stabilizing agents that function primarily by interfering with spindle microtubule dynamics causing cell cycle arrest and apoptosis. However, the mechanisms underlying their action have yet to be fully elucidated. These agents have become widely recognized as active chemotherapeutic agents in the treatment of metastatic breast cancer and early-stage breast cancer with benefits gained in terms of overall survival (OS) and disease-free survival (DFS). However, even with response to taxane treatment the time to progression (TTP) is relatively short, prolonging life for a matter of months, with studies showing that patients treated with taxanes eventually relapse. This review focuses on chemoresistance to taxane treatment particularly in relation to the spindle assembly checkpoint (SAC) and dysfunctional regulation of apoptotic signaling. Since spindle microtubules are the primary drug targets for taxanes, important SAC proteins such as MAD2, BUBR1, Synuclein-gamma and Aurora A have emerged as potentially important predictive markers of taxane resistance, as have specific checkpoint proteins such as BRCA1. Moreover, overexpression of the drug efflux pump MDR-1/P-gp, altered expression of microtubule-associated proteins (MAPs) including tau, stathmin and MAP4 may help to identify those patients who are most at risk of recurrence and those patients most likely to benefit from taxane treatment.

Priorities in colorectal cancer research: recommendations from the Gastrointestinal Scientific Leadership Council of the Coalition of Cancer Cooperative Groups

Emerging technologies have greatly expanded our ability to detect, characterize, and treat colorectal cancer. The Coalition of Cancer Cooperative Groups convened a multidisciplinary panel, the Scientific Leadership Council in GI cancer, to discuss and advise on the priorities and opportunities to advance current and future approaches into the clinical arena to impact most rapidly the morbidity and mortality from this disease. The Council's recommendations for research priorities are the result of engagement of community and academic oncologists, patient advocacy groups, and other stakeholders including the pharmaceutical industry and governmental agencies. We detail some key prospects for investigation in the areas of colon cancer detection, prevention, and surgical and medical management. Many are in early or definitive clinical trials, and a focus on rapid accrual is urged. The implementation of biology-directed laboratory investigations, both in association with ongoing clinical trials and as a separate developmental strategy for targeted therapies, is supported as the route to individualized therapy.

In vitro chemosensitivity of freshly explanted tumor cells to pemetrexed is correlated with target gene expression

AIM OF THE STUDY

mRNA expression of genes involved in the mechanism of action of pemetrexed was correlated with in vitro chemosensitivity of freshly explanted human tumor specimens.

EXPERIMENTAL DESIGN

Chemosensitivity to pemetrexed was studied in soft-agar. Multiplex rtPCR experiments for reduced folate carrier (RFC), folate receptor-alpha (FR-alpha), folylpolyglutamate synthetase (FPGS), thymidylate synthase (TS), dihydrofolate reductase (DHFR), glycinamide ribonucleotide formyl transferase (GARFT), mrp4, and mrp5 were performed in parallel. Correlations, threshold optimization, sensitivity, specificity, and efficiency were analyzed using the appropriate statistical methodologies.

RESULTS

In 61 samples, low levels of TS, GARFT, DHFR, and mrp4 gene expression significantly correlated with chemosensitivity to pemetrexed. Optimization analyses demonstrated threshold values of 144 copies for TS and six copies for mrp4 relative to 10(4) copies of beta-actin.

CONCLUSIONS

These results form a rational basis for the design of clinical trials to evaluate the expression of these enzymes as predictors for treatment outcome.

p53 protein accumulation as a prognostic marker in sporadic colorectal cancer

BACKGROUND AND AIMS

p53 protein plays a crucial role in the pathogenesis of a large number of malignancies. In this study, our goal was to elucidate the prognostic role of p53 overexpression and its relationship to clinicopathological variables in colorectal cancer.

MATERIALS AND METHODS

Between 1999 and 2004, surgical specimens of 258 patients who received surgical treatment for colorectal cancer at the Veterans General Hospital, Taipei were collected. p53 expression in tumor tissue was evaluated by immunohistochemical analysis using the human p53-specific mouse monoclonal antibody, PAb 1801.

RESULTS

Of the 258 patients, 97 (37.6%) had overexpression of p53 in tumor tissues. The accumulation of p53 protein in tumor tissues did not correlate with age, gender, preoperative serum carcinoembryonic antigen (CEA) level, mucin content, nodal status, and tumor stage. A statistically significant correlation was found between p53 overexpression and location of the tumor in the rectum (p=0.038). Well to moderately differentiated tumors had significantly higher frequency of p53 overexpression than poorly differentiated tumors (40.0 vs 20.0%, p=0.050). Each patient was followed up for a minimum of 2 years (median 35 months). In univariate analysis, 3-year cancer-specific survival rate was significantly higher in patients with tumor p53 overexpression (88.2%) than in patients without overexpression (log rank test, p=0.037). However, in multivariate analysis, the tumour node metastasis stage remained the most significant independent prognostic factor.

CONCLUSION

The accumulation of p53 protein might have a favorable prognostic value in colorectal cancer, but it is not an independent prognostic factor.

The prognostic significance of thymidylate synthase and dihydropyrimidine dehydrogenase in colorectal cancer of 303 patients adjuvantly treated with 5-fluorouracil

Cytotoxic effect of 5-fluorouracil 5-FU is mediated through inhibition of thymidylate synthase (TS), and 5-FU is catabolised by dihydropyrimidine dehydrogenase (DPD). Efficacy of 5-FU may therefore depend on the TS and DPD activity of colorectal cancer. Archival tumour specimens from 303 consecutive patients were analysed for the expression of TS and DPD using immunohistochemistry. All patients were completely resected for colorectal cancer stages II-III and have subsequently received adjuvant treatment with 5-FU. In a multivariate analysis adjusting for the impact of bowel obstruction and vascular tumour invasion, diffuse TS pattern was significantly associated with increased risk of recurrence (hazard ratio (HR) = 1.9; 95% confidence interval (CI): 1.1-3.2; p = 0.02), but without significant association to death (HR = 1.6; 95% CI: 0.9-2.8; p = 0.08). High TS intensity was not significantly associated with lower risk of recurrence (HR = 0.6; 95% CI: 0.3-1.1; p = 0.07) or death (HR = 0.6; 95% CI: 0.3-1.2; p = 0.2). High DPD intensity was significantly associated with increased risk of recurrence (HR = 1.5; 95% CI: 1.1-2.3; p = 0.03) and death (HR = 1.6; 95% CI: 1.1-2.5; p = 0.02). Patients with a combination of low TS and high DPD intensity were at significantly increased risk of both recurrence (HR = 2.1; 95% CI: 1.0-4.2; p = 0.04) and death (HR = 2.0; 95% CI: 1.0-4.0; p = 0.05). No relationship between tolerability and toxicity of 5-FU and TS and DPD expression was found. It is concluded that characterizing colorectal carcinomas by TS and DPD expression may disclose subsets of patients with significantly greater risk of disease recurrence and early death. This may be utilized in the selection of patients for treatment approaches and for decision on follow-up programs.

Molecular markers that predict response to colon cancer therapy

Progress in the treatment of colon cancer depends on the development of target-based molecules built on an improved understanding of the molecular biology of the disease. Defining end points for chemotherapy resistance is needed as drug resistance develops quickly and patients demonstrate variation in response to chemotherapy. Many techniques that measure a marker's preponderance have been developed including biochemical, immunohistochemical, genomics, proteomics or a combination thereof. However, standardization of these techniques that measure either genes or their protein products is urgently needed. This article reviews several markers (TS,TP, DPD, FT, EGFR, VEGF, CD44v6, TRAIL, microsatellite instability, allelic deletions, oncogenes and suppressor genes [c-myc, Ki-Ras, p53, p21, Topo I, Topo IIalpha, Fos, hMLH1, Bcl-2/Bax and MDR1], MDR-related proteins [Pgp, MRP and LRP], genomic polymorphisms [XPD, ERCC1, GSTP1 and TS 3 -UTR] and COX-;2) that influence DNA metabolism, DNA damage, programmed cell death, the immune or vascular system, or lead to mutations. When combined together and tested by newly developed genomic and proteomic approaches, many of these markers provide a more sensitive indicative predictor of response than when evaluated separately or by older biochemical, immunohistologic or morphologic methods. A global approach involving the simultaneous testing of several predictive multimarkers will provide critical information for improving chemotherapy to alleviate suffering from this disease.

Predictive role of thymidylate synthase, dihydropyrimidine dehydrogenase and thymidine phosphorylase expression in colorectal cancer patients receiving adjuvant 5-fluorouracil

OBJECTIVE

The combined assessment of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) gene expressions in metastatic colorectal cancer has been reported to be able to predict the efficacy of fluoropyrimidine-based chemotherapy. In order to evaluate the prognostic role in the adjuvant setting, we investigated the TS, DPD and TP expression in primary tumors of colorectal cancer patients treated with 5-fluorouracil (5-FU).

METHODS

TS, DPD and TP expression levels were determined by immunohistochemistry in paraffin-embedded primary tumor tissues from 62 patients with Dukes' stage B and C colorectal cancers who underwent surgery and received adjuvant systemic chemotherapy with 5-FU. The median follow-up was 90 months (range 17-127).

RESULTS

Dukes' stage C cancer and high TS expression were independent markers of poor prognosis for disease-free survival (DFS; p = 0.0009 and p = 0.007, respectively) and overall survival (OS; p = 0.0005 and p = 0.011, respectively). By multivariate analysis, patients with high DPD expression had significantly shorter DFS (p = 0.007) and OS (p = 0.005) compared to patients with low DPD expression. In the combined analysis of 2 markers, patients with low TS and low DPD had the best outcome in terms of DFS (p = 0.007) and OS (p = 0.03). The analysis of all 3 proteins showed that the patients with low expression of all 3 markers had significantly longer DFS (p = 0.04) and OS (p = 0.01) than patients with a high value of any one of the protein expressions. However, the joint analysis of 3 markers (group with TS-/DPD-/TP-) could not identify a subgroup of patients with a better prognosis compared to the analysis of 2 markers (group with TS-/DPD-). The analysis of Dukes' stage C cancer patients confirmed a significant benefit in terms of DFS and OS (p = 0.001 and p = 0.006, respectively) when all 3 markers had low expression. We also found a positive significant correlation between TS and TP protein expression (p = 0.033).

CONCLUSIONS

This retrospective investigation suggests that the combined assessment of TS and DPD may be useful to evaluate the prognosis of patients with Dukes' B and C colon carcinoma receiving 5-FU adjuvant chemotherapy. The role of TP as a predictor for 5-FU-based therapy needs further investigations.

Thymidylate synthase expression in colon carcinomas with microsatellite instability

PURPOSE

Colon cancer cells with high-frequency microsatellite instability (MSI-H) display resistance to 5-fluorouracil (5-FU) that can be reversed by restoring DNA mismatch repair (MMR) proficiency. Given that thymidylate synthase (TS) is inhibited by 5-FU, we studied the relationship between MSI and TS expression, and the prognostic effect of these and other markers (i.e., p53 and 17p allelic imbalance).

EXPERIMENTAL DESIGN

Dukes' stage B2 and C colon carcinomas (n = 320) from participants in 5-FU-based adjuvant therapy trials were analyzed for MSI and 17p allelic imbalance. Expression of MMR (hMLH1, hMSH2), TS, and p53 proteins were analyzed by immunohistochemistry. Correlations between markers and associations with overall survival were determined.

RESULTS

Of 320 cancers studied, 60 (19%) were MSI-H. TS expression variables were similar in MSI-H and microsatellite stable/low-frequency MSI (MSS/MSI-L) cancers, and unrelated to MMR proteins. MSI-H tumors had lower stage (P = 0.0007), fewer metastatic lymph nodes (P = 0.004), and improved overall survival (P = 0.01). Loss of MMR proteins was also associated with better overall survival (P = 0.006). None of the TS variables were prognostic. Histologic grade (P = 0.0008) and nodal status (P = 0.0002) were associated with overall survival, in contrast to 17p allelic imbalance or p53. Only MSI status or loss of MMR proteins, histologic grade, and tumor stage were independent markers for overall survival.

CONCLUSIONS

MSI-H tumors show earlier stage at presentation and better stage-adjusted survival rates. MSI status and TS expression were unrelated and TS was not prognostic, suggesting that TS levels cannot explain therapeutic resistance to 5-FU reported in MSI-H colon cancers.

Drug resistance, predictive markers and pharmacogenomics in colorectal cancer

Resistance to chemotherapy limits the effectiveness of current cancer therapies, including those used to treat colorectal cancer, which is the second most common cause of cancer death in Europe and the United States. 5-Fluorouracil-based chemotherapy regimens are the standard treatment for colorectal cancer in both the adjuvant and advanced disease settings. Drug resistance is thought to cause treatment failure in over 90% of patients with metastatic cancer, while drug resistant micrometastic tumour cells may also reduce the impact of adjuvant chemotherapy treatment. The identification of panels of biomarkers that not only identify those patients most likely to benefit from chemotherapy treatment, but also which chemotherapies to use, would be a major advance. In this review, we describe molecular mechanisms of drug resistance that may be relevant to colorectal cancer. We also describe the results of predictive biomarker studies in this disease. Finally, we discuss how pharmacogenomics and other high through-put technologies may impact on the clinical management of colorectal cancer in the future.

High-grade and hormone-treated prostate cancer express high levels of thymidylate synthase

OBJECTIVE

To evaluate the expression of thymidylate synthase and dihydropyrimidine dehydrogenase in prostate tissue.

MATERIALS AND METHODS

Tissue from 79 patients with localized prostate cancer was used. Thymidylate synthase and dihydropyrimidine dehydrogenase expression were determined semiquantitatively by immunohistochemistry.

RESULTS

Thymidylate synthase and dihydropyrimidine dehydrogenase immunostaining grades of benign tissue were significantly higher than those of cancer tissue (both P < 0.01). Cancer tissue with a primary Gleason grade of > or = 4 expressed a higher thymidylate synthase staining grade than those with a primary Gleason grade of <4 (P < 0.01). Cancer tissue spots from patients treated with neoadjuvant therapy revealed significantly higher thymidylate synthase and dihydropyrimidine dehydrogenase grades than those with no neoadjuvant therapy (P < 0.01).

CONCLUSION

High thymidylate synthase expression in localized prostate cancer might reflect an aggressive status. High expression in high-grade prostate cancers and prostate cancers after hormonal therapy suggest that thymidylate synthase could be a new therapeutic target for advanced prostate cancer.

Inter-relationship between microsatellite instability, thymidylate synthase expression, and p53 status in colorectal cancer: implications for chemoresistance

Background

Studies indicate that thymidylate synthase (TS) expression, p53 and mismatch repair status have potential to influence colorectal cancer (CRC) outcome. There is, however, little data on the inter-relationship between these three markers. We sought to investigate whether relationships exist between these markers that might contribute to CRC phenotypes.

Methods

Four hundred and forty-one stage I-III CRCs were investigated. p53 status and TS expression were assessed by standard immunohistochemistry methods. Mismatch repair status was determined by assessment of microsatellite instability (MSI) using radiolabelled microsatellite genotyping.

Results

244 tumours (55%) over-expressed p53, and 259 (58%) expressed high TS levels. 65 tumours (15%) had MSI. A significant relationship between p53 over-expression and high TS expression was observed (p = 0.01). This was independent of MSI status. A highly significant inverse relationship between MSI and p53 status was observed (p = 0.001). No relationship was seen between MSI status and TS expression (p = 0.59).

Conclusion

Relationships exist between p53 status and TS expression, and MSI and p53 status. These inter-relationships may contribute to the clinical phenotype of CRCs associated with each of the molecular markers. High TS expression is unlikely to account for the clinical behaviour of CRCs with MSI.

Does Biomolecular Characterization of Stage II/III Colorectal Cancer Have Any Prognostic Value?

As new improvements in the treatment of colorectal cancer have become available, it has become important to understand the benefits of new therapies or the deleterious effects stemming from the increased risk of toxicity. In particular, a more rational approach to adjuvant chemotherapy for patients with stage II/III disease should be defined by understanding which patients have a higher recurrence risk. Many studies have investigated several molecular markers, but none has been definitively associated with patient outcome. We present a review of studies that have evaluated the immunohistochemical correlation between expression of some biomarkers, such as thymidylate synthase, p53, Ki-67, Bcl-2, and microsatellite instability status expressed by Mut-L homologue 1 and Mut-S homologue 2 proteins, and the prognosis of patients with stage II/III colorectal cancer. We have evaluated studies in which > or = 100 patients were involved in an effort to ensure a representative study group. The only biomarker likely to have a prognostic value is microsatellite instability status, which correlated with a better prognosis.

Nuclear Maspin expression is associated with response to adjuvant 5-fluorouracil based chemotherapy in patients with stage III colon cancer

Maspin, a member of the Serpin protease inhibitor family, is overexpressed in poorly differentiated colorectal tumors and more frequently found in tumors with microsatellite instability. Immunohistochemical nuclear Maspin staining is predominantly seen in tumor cells at the invasion front of such cancers, suggesting that this molecule is associated with local tumor cell infiltration and aggressiveness. In a retrospective study, we studied nuclear Maspin expression as a potential prognostic tool in a total of 172 primary stage III colon cancers by immunohistochemistry. Of those 172 patients, 76 were treated by surgery only, and 96 patients received additional adjuvant 5-fluorouracil (5-FU) based chemotherapy. Nuclear Maspin expression was an independent adverse prognostic factor for overall survival in our patient cohort (hazard ratio 2.08; 95% CI, 1.13-3.81; p = 0.018). However, patients with primary tumors expressing Maspin in the nucleus showed a significant treatment benefit from 5-FU chemotherapy (hazard ratio 0.384; 95% CI, 0.188-0.784; p = 0.009) compared to adjuvantly treated patients whose tumors did not express this molecule. Nuclear Maspin expression is highly predictive of 5-FU chemotherapy response in patients with advanced stage colon cancer. Patients with negative immunohistochemical Maspin expression do not benefit from 5-FU treatment and may be candidates for an alternative (non-5-FU based) adjuvant therapy regime.

Thymidine phosphorylase, dihydropyrimidine dehydrogenase and thymidylate synthase mRNA expression in primary colorectal tumors-correlation to tumor histopathology and clinical follow-up

AIM

Evaluation of thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), and thymidylate synthase (TS) mRNA levels in formalin-fixed, and paraffin-embedded tissues of patients with colorectal cancer and their prognostic and/or predictive value.

MATERIALS AND METHODS

Total RNA was isolated from microdissected, formalin-fixed, and paraffin-embedded tissues (controls and tumor) and subjected to quantitative RT-PCR (QRT-PCR) in the LightCycler system. Resulting mRNA levels correlated to tumor histology (n=102) and the clinical follow-up in patients treated by resection alone (n=40) and by resection plus adjuvant 5-FU-based chemotherapy (n=52).

RESULTS

Correlation to histopathological parameters revealed a significant association between tumor stage and the TP mRNA level (T and N category and UICC) as well as the TP:DPD (T and N category and UICC) and TS:DPD (T category) ratio. In addition, tumor differentiation was correlated to the TS mRNA level and the TS:DPD ratio. Finally, the TS:DPD ratio was a prognostic marker for overall survival in patients receiving resection alone (p=0.032). Moreover, a high TP:DPD ratio (>8.1; p=0.002) and, marginally, low DPD (<8.2; p=0.05) mRNA levels significantly correlated to disease-free survival.

CONCLUSION

We present a novel, standardized approach for TP, DPD, and TS mRNA quantification in archival tissue specimens and applied this to a large series of primary colorectal tumors. Correlations to histopathological parameters and clinical follow-up revealed an association of TP, DPD and TS mRNA expression patterns with tumor stage and suggested new prognostic and predictive markers for patients with colorectal cancer.

[Variation in the prognostic value of p53 protein in relation to tumoral stage in patients with colorectal adenocarcinoma]

OBJECTIVE

To analyze the prognostic value of p53 protein as a marker of recurrence risk in each tumoral stage.

PATIENTS AND METHOD

A prospective study of a cohort of 288 patients who underwent surgery for colorectal adenocarcinoma was performed. Stage 1 of the tumor-node-metastasis (TNM) classification was found in 42 patients (14.6%), stage II in 144 (50%) and stage III in 102 (35.4%). Histopathological variables were examined in tumor samples fixed in formol and embedded in paraffin and p53 (DO7 antibody) and proliferative cell nuclear antigen (PC-10 antibody) proteins were determined using immunohistochemistry. The results of p53 were analyzed in each of the categories of clinical and histopathological variables. Recurrence-free survival was calculated using the Kaplan-Meier method. The value of each variable as a predictive marker for tumoral recurrence was analyzed using Cox regression analysis. Hazard ratios and 95% confidence intervals were calculated as indicators of relative risk. The analysis was applied to the whole cohort and was subsequently repeated in each TNM tumoral stage separately.

RESULTS

Tumors with p53 protein overexpression more frequently recurred and showed lower recurrence-free survival at 5 years. However, the association between p53 expression and postoperative outcome was statistically significant in stage III tumors only. In this subgroup of patients, recurrence-free survival at 60 months was 60% in p53-negative tumors and was 26% in p53-positive tumors (p=0.010). In the multivariate analysis, p53 was an independent prognostic factor associated with a high risk of recurrence in stage III tumors (hazard ratio=2.76; 95% CI, 1.29-5.9; p=0.009). Overexpression of p53 showed prognostic value as a marker of high risk of recurrence in the form of metastases (hazard ratio=2.23; 95% CI, 1.04-4.75), but not as a prognostic marker of locoregional recurrence. No relationship was found between the state of p53 protein and the effect of postoperative adjuvant therapy.

CONCLUSION

The p53 protein does not have the same prognostic value in all tumoral stages. This protein is only predictive of high recurrence risk in the subgroup of patients with stage III tumors.