Chemistry of Fluorinated Pyrimidines in the Era of Personalized Medicine.

We review developments in fluorine chemistry contributing to the more precise use of fluorinated pyrimidines (FPs) to treat cancer. 5-Fluorouracil (5-FU) is the most widely used FP and is used to treat > 2 million cancer patients each year. We review methods for 5-FU synthesis, including the incorporation of radioactive and stable isotopes to study 5-FU metabolism and biodistribution. We also review methods for preparing RNA and DNA substituted with FPs for biophysical and mechanistic studies. New insights into how FPs perturb nucleic acid structure and dynamics has resulted from both computational and experimental studies, and we summarize recent results. Beyond the well-established role for inhibiting thymidylate synthase (TS) by the 5-FU metabolite 5-fluoro-2'-deoxyuridine-5'-O-monophosphate (FdUMP), recent studies have implicated new roles for RNA modifying enzymes that are inhibited by 5-FU substitution including tRNA methyltransferase 2 homolog A (TRMT2A) and pseudouridylate synthase in 5-FU cytotoxicity. Furthermore, enzymes not previously implicated in FP activity, including DNA topoisomerase 1 (Top1), were established as mediating FP anti-tumor activity. We review recent literature summarizing the mechanisms by which 5-FU inhibits RNA- and DNA-modifying enzymes and describe the use of polymeric FPs that may enable the more precise use of FPs for cancer treatment in the era of personalized medicine.

A prognostic analysis of 895 cases of stage III colon cancer in different colon subsites.

PURPOSE: Stage III colon cancer is currently treated as an entity with a unified therapeutic principle. The aim of the retrospective study is to explore the clinicopathological characteristics and outcomes of site-specific stage III colon cancers and the influences of tumor location on prognosis. METHODS: Eight hundred ninety-five patients with stage III colon cancer treated with radical operation and subsequent adjuvant chemotherapy (5-fluorouracil/oxaliplatin) were divided into seven groups according to colon segment (cecum, ascending colon, hepatic flexure, transverse colon, splenic flexure, descending colon, and sigmoid colon). Expression of excision repair cross-complementing group 1 (ERCC1) and thymidylate synthase (TS) was examined by immunohistochemistry. We assessed if differences exist in patient characteristics and clinic outcomes between the seven groups. RESULTS: There were significant differences in tumor differentiation (P < 0.001), T stage (P < 0.001), N stage (P < 0.001), American Joint Committee on Cancer (AJCC) tumor-node-metastasis (TNM) stage (P < 0.001), metachronous liver metastasis (P < 0.001), metachronous lung metastasis (P < 0.001), and ERCCI expression (P < 0.001) between the seven groups. Both 5-year recurrence-free survival (RFS) and 5-year overall survival (OS) exhibited significant differences (both P < 0.001) with survival gradually decreasing from cecum to sigmoid colon. Cox regression analyses identified that tumor location was an independent prognostic factor for RFS and OS. CONCLUSIONS: Stage III colon cancer located proximally carried a poorer survival than that located distally. Different efficacies of FOLFOX adjuvant chemotherapy may be an important factor affecting survival of site-specific stage III colon cancers.

Can we improve the clinical risk score? The prognostic value of p53, Ki-67 and thymidylate synthase in patients undergoing radical resection of colorectal liver metastases.

OBJECTIVES: The aim of this study was to assess whether biological markers can provide prognostic information additional to that supplied by the clinical risk score (CRS) in patients with colorectal liver metastases. METHODS: A retrospective review of a prospectively maintained database was conducted. Patients selected for this study were treated between 1996 and 2011 with potentially curative liver surgery. Expressions of p53, Ki-67 and thymidylate synthase were assayed using immunohistochemical techniques on tissue microarrays. RESULTS: A total of 98 (24%) of 406 patients met the inclusion criteria. The median follow-up was 103 months. Analysis revealed a correlation between p53 protein overexpression and high CRS (P = 0.058). Following multivariate analysis, only high CRS remained as an independent negative prognostic predictor of survival (P = 0.018), as well as an indicator of early recurrence of disease (P = 0.010). Of the biological markers investigated, only Ki-67 overexpression was identified as a positive predictor of survival on multivariate analysis (P = 0.038). CONCLUSIONS: Ki-67 overexpression was a positive predictor of survival. Only high CRS remained an independent negative prognostic predictor.

[Morphological assessment of predictive factors in adenocarcinoma of the colon].

Immunohistochemical investigation of 15 different markers in colon adenocarcinoma was carried out. Prognostic significance showed chemokine receptor CXCR4 and Ki-67. Predictive significance was revealed for thymidylate synthase (TS) and thymidine phosphorylase (TP).

Differential expression and prognostic value of ERCC1 and thymidylate synthase in resected gastric adenocarcinoma.

BACKGROUND: Excision repair cross-complementing gene-1 (ERCC1) and thymidylate synthase (TS) are key regulatory enzymes whose expression patterns are associated with overall survival (OS) in several malignancies. Their expression patterns and prognostic value in resected gastric adenocarcinoma (GAC) are not known. METHODS: In total, 109 patients who underwent resection for GAC between January 2000 and June 2011 had tissue available for analysis. The primary objective was to assess for the differential expression of ERCC1 and TS using immunohistochemistry. The secondary objective was to assess for the association between OS and the expression of ERCC1 and TS. RESULTS: The median follow-up was 21.2 months, and the median OS was 28.8 months. Resected GAC exhibited differential expression of ERCC1 (high expression, 23%; n = 25) and TS (high expression, 43%; n = 47). ERCC1 and TS expression were not associated with OS. In a subset analysis of patients who received chemotherapy (n = 73), high ERCC1 expression was associated with decreased OS (16.7 months vs 53.8 months; P = 0.03). After controlling for known adverse pathologic features, high ERCC1 expression persisted as a negative prognostic factor in multivariate Cox regression analysis (hazard ratio, 2.5; 95% confidence interval, 1.03-6.0; P = .04). Conversely, in patients who underwent resection only (n = 35), high ERCC1 expression demonstrated a trend toward improved OS (40.4 months vs 12.7 months; P = .10); a positive prognostic influence also was present on multivariate analysis (hazard ratio, 0.20; 95% confidence interval, 0.04-0.86; P = .03). CONCLUSIONS: Resected GAC exhibited differential expression of TS and ERCC1. Among all patients, ERCC1 and TS expression levels were not associated with OS. High ERCC1 tumor expression was associated with decreased OS in the patients who received chemotherapy but was associated with increased OS in those who underwent surgery alone. ERCC1 expression had prognostic value in resected gastric cancer, and further investigation is warranted.

Assessment of thymidylate synthase expression in biopsy specimens and corresponding resection specimens of non-small-cell lung cancer.

AIMS: Pemetrexed (Pem) is a potent inhibitor of thymidylate synthase (TS), and has shown efficacy in the treatment of non-small-cell lung cancer (NSCLC). TS expression in NSCLC biopsy specimens may correlate with the tumour responses to TS-inhibiting agents. As TS is not homogeneously expressed, our aim was to test whether TS expression in biopsy specimens may be representative for the whole tumour and can be used for therapeutic assessment. METHODS AND RESULTS: We immunohistochemically analysed TS expression in biopsy and corresponding resection specimens of 100 consecutive NSCLCs. The samples were subgrouped according to TS expression levels, and the degree of agreement between the biopsy and the corresponding resection specimen was calculated. TS expression-based grouping according to one cut-off criterion (high or low expression) led to concordant results between biopsy and resection specimens. When more than one cut-off criterion was used, the results were significantly different. CONCLUSIONS: Thymidylate synthase expression levels in NSCLC biopsy specimens may correspond to TS expression of the whole tumour when robust scoring systems are applied. Further studies are needed to determine whether high or low TS expression in NSCLC biopsy specimens is of predictive value, and whether it may allow the selection of patients who will benefit from Pem treatment.

Thymidylate synthase (TS) protein expression as a prognostic factor in advanced colorectal cancer: a comparison with TS mRNA expression.

BACKGROUND/AIMS: The role of intratumoral thymidylate synthase (TS) mRNA or protein expression is still controversial and little has been reported regarding relation of them in colorectal cancer. METHODOLOGY: Forty-six patients with advanced colorectal cancer who underwent surgical resection were included. TS mRNA expression was determined by the Danenberg tumor profile method based on laser-captured micro-dissection of the tumor cells. TS protein expression was evaluated using immunohistochemical staining. RESULTS: TS mRNA expression tended to relate TS protein expression. Statistical significance was not found in overall survival between the TS mRNA high group and low group regardless of performing adjuvant chemotherapy. The overall survival in the TS protein negative group was significantly higher than that in positive group in all and the patients without adjuvant chemotherapy. Multivariate analysis showed TS protein expression was as an independent prognostic factor. CONCLUSIONS: TS protein expression tends to be related TS mRNA expression and is an independent prognostic factor in advanced colorectal cancer.

Correlations between clinicopathological parameters and molecular signatures of primary tumors for patients with stage T3n0 colorectal adenocarcinomas: a single center retrospective study on 100 cases.

BACKGROUND/AIMS: To examine the clinical and protein expression characteristics of tumor tissues for prediction of prognosis in colorectal cancer (CRC). METHODOLOGY: We retrospectively analyzed the clinicopathological data of patients with stage T3N0 CRC, operated between 1997-2003 and the surgical materials for the relation between disease prognosis and p53, p21, p16, ß-catenin, E-cadherin, EGFR, hMLH1, hMSH2 and TS protein expressions. RESULTS: A significantly shorter 3-year disease free survival was observed in patients under the age of 50. The worst 5-year overall survival (OS) observed for patients over 70. Tumor localization and number of processed lymph nodes significantly affected prognosis. The EGFR, hMSH2 and TS expressions and the 5-fluorouracyl treatment were not found to be of prognostic value; p53 and p21 positivity had significantly worse survival. When ß-catenin membrane expression disappeared on tumor cells, the 5-year OS rate decreased and time to metastasis shortened significantly. Membrane ß-catenin expression, processed lymph nodes number and age were detected as independent prognostic markers. CONCLUSIONS: These results suggest that the evaluation of a clinicopathological profile, based on age, tumor localization, number of examined lymph nodes, p53, p21 and E-cadherin ß-catenin expression appears to be useful in identifying high risk patients.

Thymidylate synthase and cyclin D1 protein expression in lymph node negative colorectal cancer: role as prognostic factors?

BACKGROUND/AIMS: Thymidylate synthase (TS) is an enzyme for DNA-synthesis and the target for 5-fluorouracil whereas cyclin-D1 plays a critical role in the progression of cells through the G1 phase of the cell-cycle. There is evidence that expression of these markers may predict the outcome of patients with colorectal cancers. The aim of this study was to examine the prognostic value of TS and cyclin D1 protein expression in patients with node negative colorectal cancers. METHODOLOGY: TS and cyclin D1 protein expression from 140 patients with UICC stage I and II colorectal cancer was analyzed by immunhistochemistry in paraffin-embedded primary tumour specimens. RESULTS: The 1-, 5- and 10-year overall-survival rates were 96%, 86% and 71%, respectively. Tumour stage and recurrence were associated with overall-survival. Low- and high TS immunoreactivity was present in 68 (48%) and 72 (52%) of cancers, respectively. Low- and high cyclin D1 immunoreactivity was present in 98 (70%) and 42 (30%) of the cancers, respectively. Patients (n=72) with high TS expressing tumours had a worse overall-survival than patients (n=68) with low TS expressing colorectal cancers (p=0.011). No difference in overall-survival was seen between patients with high and low cyclin D1 expressing cancers. CONCLUSIONS: TS may be helpful as a prognostic marker in lymph node negative colorectal cancer.

Predictive value of expression of ERCC 1 and GST-p for 5-fluorouracil/oxaliplatin chemotherapy in advanced colorectal cancer.

BACKGROUND/AIMS: The aim of this study was to determine whether expression of the excision repair cross complementing protein (ERCC1), glutathione S-transferase pi (GST-p) and thymidylate synthase (TS) predict response in patients with advanced colorectal cancer treated with 5-fluorouracil/oxaliplatin chemotherapy. METHODOLOGY: The study population consisted of 39 patients with advanced colorectal cancer (median age, 65 years). Patients were treated with the modified FOLFOX 6 regimen. The expression of ERCC-1, GST-p and TS of primary tumors were examined by immunohistochemistry. RESULTS: The response rate of modified FOLFOX 6 chemotherapy was 51.3%. The positive rates of ERCC-1, GST-p and TS were 43.6%, 33.3% and 66.7%, respectively. The patients without ERCC-1 (p=0.0248) or GST-p? (p=0.0019) expression were more likely to respond to chemotherapy. TS expression did not correlate with chemotherapeutic response. CONCLUSIONS: Immunohistochemical studies for ERCC-1 and GST-p may be useful in prediction of the response to 5-fluorouracil/oxaliplatin chemotherapy in advanced colorectal cancer patients.

[Effect of pemetrexed plus platinum for chemotherapy-naive advanced non-small cell lung cancer].

OBJECTIVE: To evaluate the effect of pemetrexed plus platinum for chemotherapy-naive advanced non-small cell lung cancer (NSCLC), and to explore thymidylate synthetase (TS) expression as the predictive and prognostic factor for this treatment. METHODS: This retrospective study enrolled 51 patients with chemotherapy-naive advanced NSCLC (non-squamous) treated at Department of Thoracic Medical Oncology in Beijing Cancer Hospital from Jan 2008 to Oct 2009. All patients received pemetrexed plus platinum as first-line treatment. TS expression was detected in 30 patients who had enough tissue samples by immunohistochemistry. RESULTS: The objective response rate (ORR) was 37.3%. Median progression-free survival (PFS) was 5.3 months (95%CI: 3.9 - 6.7), and median overall survival (OS) was 19.0 months (95%CI: 11.6 - 26.4). Univariate analysis showed that gender, pathology, smoking status and response were significantly correlated with OS. Cox-regression analysis showed that pathology was an independent prognostic factor. Rate of Grade 3/4 adverse events was low. In 30 patients with enough tissue samples were available, TS expression positive rate was 33.3% (10/30). Chi-square test showed that TS expression was not associated with ORR. Multivariate analysis showed that pathology, response and TS expression (P = 0.003, 0.005 and 0.001, respectively) were the prognostic factors. CONCLUSION: The therapeutic effect and tolerance of pemetrexed plus platinum regiment were definite as first-line treatment for chemotherapy-naive advanced NSCLC, and TS expression was an independent prognostic factor.

Is there a correlation between molecular markers and response to neoadjuvant chemoradiotherapy in locally advanced squamous cell esophageal cancer?

PURPOSE: To evaluate the expression of epidermal growth factor receptor (EGFR), p53, p21 and thymidylate synthase (TS) in a pretherapy biopsy specimen of locally advanced squamous cell esophageal cancer and correlate these markers with response to neoadjuvant chemoradiotherapy. METHODS: Sixty-two patients with histopathologically proven locally advanced (T3 or greater) squamous cell esophageal cancer were enrolled. The expression of EGRF, p53, p21 and TS markers was assessed with immunohistochemistry. Semiquantitative assessment of expression of these markers was performed based on the percent of the stained cells. Radiotherapy (45-50.4 Gy) was delivered concomitantly with 5-fluorouracil (5-FU)/leucovorin (LV)/cisplatin (CIS) chemotherapy. Five to 6 weeks after chemoradiation, response to treatment was assessed. Medically fit and operable patients were operated. The resected material underwent histopathological evaluation of tumor expansion, histological classification after initial multimodality treatment (yp TNM), residual status and tumor regression grade (TRG). RESULTS: Out of 62 patients enrolled, 41 (66%) were evaluated for molecular markers. Clinical response rate was 43.9%. Out of 41 patients, 12 (29%) underwent surgery. TRG 1 was noted in 58% of the patients. In a pretherapy tumor specimen, positive expression was noted in 80, 90, 80 and 71% for EGFR, p53, p21 and TS, respectively. We noted no statistically significant difference neither between tumor marker expression and clinical response to chemoradiation, nor between tumor marker expression and TRG. CONCLUSION: We registered no difference in response to treatment between EGFR, TS, p21 and p53 positive and negative staining.

Prognostic and predictive factors in colorectal cancer.

Colorectal cancer (CRC) is an important public health problem; it is a leading cause of cancer mortality in the industrialized world, second to lung cancer: each year there are nearly one million new cases of CRC diagnosed worldwide and half a million deaths (1). This review aims to summarise the most important currently available markers for CRC that provide prognostic or predictive information. Amongst others, it covers serum markers such as CEA and CA19-9, markers expressed by tumour tissues, such as thymidylate synthase, and also the expression/loss of expression of certain oncogenes and tumour suppressor genes such as K-ras and p53. The prognostic value of genomic instability, angiogenesis and proliferative indices, such as the apoptotic index, are discussed. The advent of new therapies created the pathway for a personalized approach of the patient. This will take into consideration the complex genetic mechanisms involved in tumorigenesis, besides the classical clinical and pathological stagings. The growing number of therapeutic agents and known molecular targets in oncology lead to a compulsory study of the clinical use of biomarkers with role in improving response and survival, as well as in reducing toxicity and establishing economic stability. The potential predictive and prognostic biomarkers which have arisen from the study of the genetic basis of colorectal cancer and their therapeutical significance are discussed.

PTEN, tau-AP-3, thymidylate synthase immunohistochemistry scoring expression in patients with uterine leiomyomas, uterine smooth muscle tumors of uncertain malignancy potential and uterine leiomyosarcomas.

Uterine smooth muscle tumors are frequently classified as benign and malignant. However, an assortment of mitotic counts and nuclear atypia can be indecisive between uncertain malignant potential, and malignant uterine smooth muscle tumors. We applied three immunohistochemical parameters to distinguish between cases of benign, malignant, and those with uncertain malignant histology.

Significance of thymidylate synthase for resistance to pemetrexed in lung cancer.

Pemetrexed (MTA) is a multitargeted antifolate with promising clinical activity in lung cancer. We exposed the small cell lung cancer cell line PC6 to stepwise-increasing pemetrexed concentrations of 0.4, 1.6, and 4.0 microm, and established three pemetrexed-resistant lung cancer cell lines: PC6/MTA-0.4, PC6/MTA-1.6, and PC6/MTA-4.0 cells. To investigate the mechanisms of acquired resistance to pemetrexed, we measured the expression levels of the thymidylate synthase (TS), reduced folate carrier (RFC), and folylpoly-gamma-glutamate synthetase (FPGS) genes. TS gene expression was significantly increased in PC6/MTA-1.6 and PC6/MTA-4.0 cells relative to parental cells in a pemetrexed dose-dependent manner. In contrast, the levels of RFC gene expression in PC6/MTA-0.4 cells and FPGS in PC6/MTA-1.6 cells were significantly decreased, whereas the levels of both genes were restored in PC6/MTA-4.0 cells. Knockdown of TS expression using siRNA enhanced pemetrexed cytotoxicity in PC6/MTA-4.0 cells. The expression level of the TS gene was significantly correlated with the concentration of pemetrexed for 50% cell survival (IC(50)) in 11 non-small cell lung cancer cell lines. These results suggest that the alteration of molecular pharmacological factors in relation with pemetrexed resistance is dose-dependent, and that up-regulation of the expression of the TS gene may have an important role in the acquired resistance to pemetrexed. In addition, TS may be a predictive marker for pemetrexed sensitivity in lung cancer.

Histone deacetylase inhibitor enhances sensitivity of non-small-cell lung cancer cells to 5-FU/S-1 via down-regulation of thymidylate synthase expression and up-regulation of p21(waf1/cip1) expression.

It is desirable to find more appropriate therapeutic opportunities in non-small-cell lung cancer (NSCLC) due to the current poor prognosis of affected patients. Recently, several histone deacetylase (HDAC) inhibitors, including suberoylanilide hydroxamic acid (SAHA), have been reported to exhibit antitumor activities against NSCLC. S-1, a novel oral fluorouracil anticancer drug, has been developed for clinical use in the treatment of NSCLC in Japan. Using an MTT assay, we analyzed the growth-inhibitory effect of 5-fluorouracil (5-FU), S-1, and SAHA against three NSCLC cell lines, as well as the breast cancer cell line MCF7 which is known to be highly sensitive to 5-FU. Combined treatment with low-dose SAHA enhanced 5-FU- and S-1-mediated cytotoxicity and resulted in synergistic effects, especially in 5-FU-resistant cells. Both the mRNA and protein expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), and orotate phosphoribosyltransferase (OPRT), which are associated with 5-FU sensitivity/response, were analyzed in the cells undergoing treatment. 5-Fluorouracil-resistant lung cancer cells displayed high expression of TS mRNA and protein. Suberoylanilide hydroxamic acid down-regulated TS mRNA and protein expression, as well as repressed the rapid induction of this factor during 5-FU treatment, in all examined cell types. We also examined the status of the Rb-E2F1 pathway, with SAHA up-regulating p21(waf1/cip1) expression via promoter histone acetylation; this, in turn, blocked the Rb-E2F1 pathway. We conclude that combination therapy with SAHA and S-1 in lung cancer may be promising due to its potential to overcome S-1 resistance via modulation of 5-FU/S-1 sensitivity-associated biomarker (TS) by HDAC inhibitor.

[The expression of thymidylate synthase (TS) and excision repair complementing-1 (ERCC-1) protein in patients with unresectable colorectal cancer treated with mFOLFOX6 therapy].

Thymidylate synthase (TS) and excision repair complementing-1 (ERCC-1) were known to be important biomarkers to predict a tumor response to 5-fluorouracil (5-FU) and oxaliplatin, but the relationship between these expressions and tumor response were still unclear. The aim of this study was to determine whether the expression of TS and ERCC-1 protein predict a tumor response in patients with unresectable colorectal cancer treated with mFOLFOX6 therapy as first-line treatment. Fifty patients with unresectable colorectal cancer treated with mFOLFOX6 therapy were enrolled in this study. The expression of TS and ERCC-1 protein in primary cancer cells were examined using immunohistochemistry. There were no significant differences between response rate and the expression of TS or ERCC-1 protein (TS: p>0.99, ERCC-1: p= 0.50). There were no significant differences between progression-free survival time and the expression of TS or ERCC-1 protein (TS: p=0.60, ERCC-1: p=0.60). In this study, the expression TS and ERCC-1 protein may not be useful for the prediction of tumor response in patients with unresectable colorectal cancer treated with mFOLFOX6 therapy.

[ERCC1 and TS expression in chemoradiotherapy treated esophageal squamous cell carcinoma].

PURPOSE: The aim of this study was to determine whether the expressions of excision repair cross-complementing-1 (ERCC1) and thymidylate synthase (TS) predict the clinical outcome of patients with esophageal squamous cell carcinoma treated with CDDP/5-FU chemoradiotherapy. PATIENTS AND METHOD: Fifteen patients with esophageal squamous cell carcinoma underwent CDDP/5-FU chemoradiotherapy. Immunohistochemical staining for ERCC1 and TS was performed using endoscopic biopsy specimens obtained prior to chemoradiotherapy. We then evaluated the response to treatment. The MIB-1 index, and the expressions of p53, p21, bax and bcl-2 were also investigated. RESULTS: ERCC1 expression was strongly detected in all of the cases. No significant relationship was observed between the response to treatment and the intensity of staining, or the percentage of cells stained. The MIB-1 index and the expressions of p53, p21, bax and bcl-2 were not associated with the response to chemoradiotherapy. CONCLUSION: In the present study, we found that the expressions of ERCC1 and TS were not suitable as predictors of the response to chemoradiotherapy.

The effect of neoadjuvant therapy on the 5-fluorouracil metabolic and relative enzymes of oral squamous cell carcinoma.

To assess the effect of neoadjuvant therapy using tegafur/uracil (UFT) and radiation therapy on the 5-fluorouracil (5-FU) metabolic and relative enzymes, thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyl transferase (OPRT) and thymidine phosphorylase (TP) in oral squamous cell carcinoma (OSCC), we examined the mRNA expression and immunohistochemical staining status of these enzymes using 17 surgical specimens. Seven patients did not receive any neoadjuvant therapy and 10 were treated with UFT and local irradiation therapy. Our result showed that the mRNA expression of these enzymes in neoadjuvant group was not significantly different from that of non-treated group using real-time quantitative PCR. To confirm the protein expression, we also carried out immunohistological staining of TS and DPD two key enzymes in the 5-FU metabolism, using the same specimens. Immunohistological staining status did not correspond to the results of mRNA analysis completely, though no significant difference between the groups was observed. Furthermore, no significant relationship between the UFT administration period and mRNA expression of the 5-FU metabolic enzymes was observed in neoadjuvant therapy group and also the distribution of the enzyme mRNA expression levels was similar to that of non-treated group. The results suggested that the neoadjuvant therapy of OSCC might not affect the expression status of 5-FU metabolic and relative enzymes in surgical tumor samples and the tumor tissues might serve as a useful specimen source to analyze the expression status of the 5-FU metabolic and relative enzymes and to determine the prospective efficiency of 5-FU-based adjuvant chemotherapy.

Immunoexpression of TS, p53, COX2, EGFR, MSH6 and MLH1 biomarkers and its correlation with degree of differentiation, tumor staging and prognostic factors in colorectal adenocarcinoma: a retrospective longitudinal study.

BACKGROUND: There are cases of colorectal tumors that, although small, show more aggressive evolution than large tumors. This motivated us to study whether there are any proteins capable of alerting about these changes. The aim here was to correlate the immunoexpression of the TS, p53, COX2, EGFR, MSH6 and MLH1 biomarkers in tumors in patients with colorectal adenocarcinoma, with the degree of cell differentiation, tumor staging and clinical-pathological prognostic factors. DESIGN AND SETTING: Retrospective observational study at a public tertiary-level hospital. METHODS: We analyzed tissue-microarray paraffin blocks of tumor tissues that had been resected from 107 patients. We used Fisher's exact test to study associations between tumor differentiation/staging and the immunoexpression of biomarkers. We also used Kaplan-Meier estimation, the log-rank test and the adjusted Cox regression model to investigate the patients' overall survival (in months) according to biomarkers and disease-free interval. RESULTS: The degree of tumor differentiation and tumor staging were not associated with the biomarkers, except in cases of patients in stages III or IV, in which there was a correlation with MLH1 expression (P=0.021). Patient survival and disease-free interval were not associated with the biomarkers. CONCLUSION: There were no associations between the degree of tumor differentiation, staging, length of survival or disease-free interval and the immunoexpression of the TS, p53, COX2, EGFR or MSH6 tumor markers. In advanced cases of colorectal adenocarcinoma (stages III and IV), there was a higher percentage of MLH1-negative results.