Thymidylate synthase, dihydropyrimidine dehydrogenase, ERCC1, and thymidine phosphorylase gene expression in primary and metastatic gastrointestinal adenocarcinoma tissue in patients treated on a phase I trial of oxaliplatin and capecitabine

Thymidine phosphorylase affects clinical outcome following surgery and mRNA expression levels of four key enzymes for 5-fluorouracil metabolism in patients with stage I and II non-small cell lung cancer

The expression levels of thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), thymidylate synthase (TS) and orotate phosphoribosyltransferase (OPRT) may predict the clinical efficacy of 5-fluorouracil-based chemotherapy in patients with cancer. We herein investigated the differences in the mRNA levels of these enzymes in non-small-cell lung cancer (NSCLC) and evaluated their prognostic value for NSCLC treated by surgical resection. The intratumoral mRNA levels of TP, DPD, TS, and OPRT were quantified in 66 patients with pathological stage I and II NSCLC (adenocarcinoma or squamous cell carcinoma) following complete resection according to the Danenberg Tumor Profile method. The TP level was the only significant prognostic factor for disease-specific survival (DSS) following complete resection; the mean TP mRNA level differed significantly between the high and low mRNA expression groups. The DSS at 5 years was significantly higher in the low TP mRNA compared with that in the high TP mRNA expression group (83.4 vs. 58.6%, respectively; P=0.005). A Cox proportional hazards model revealed that pathological stage, sex, and TP expression were independent prognostic factors for DSS in patients with stage I and II NSCLC following complete resection. Thus, TP level may be used to monitor treatment efficacy and predict the outcome of NSCLC patients.

Clinical importance of DNA repair in sporadic colorectal cancer

Colorectal cancer (CRC) is the third major cause of cancer-related deaths worldwide. However, despite the scientific efforts to provide a molecular classification to improve CRC clinical practice management, prognosis and therapeutic decision are still strongly dependent on the TNM staging system. Mismatch repair system deficiencies can occur in many organs, but it is mainly a hallmark of CRC influencing clinical outcomes and response to therapy. This review will discuss the effect of the modulation of other DNA repair pathways (direct, excision and double strand break repairs) in the clinical and pathological aspects of colorectal cancer and its potential as prognostic and predictive biomarkers.

Excision Repair Cross-complementation Group 1 is a Prognostic Biomarker in Patients with Colorectal Cancer Receiving Chemotherapy

Background:

Conflicting results about the association between expression level of excision repair cross-complementation group 1 (ERCC1) and clinical outcome in patients with colorectal cancer (CRC) receiving chemotherapy have been reported. Thus, we searched the available articles and performed the meta-analysis to elucidate the prognostic role of ERCC1 expression in patients with CRC.

Methods:

A thorough literature search using PubMed (Medline), Embase, Cochrane Library, Web of Science databases, and Chinese Science Citation Database was conducted to obtain the relevant studies. Pooled hazard ratios (HRs) or odds ratios (ORs) with 95% confidence intervals (CIs) were calculated to estimate the results.

Results:

A total of 11 studies were finally enrolled in this meta-analysis. Compared with patients with lower ERCC1 expression, patients with higher ERCC1 expression tended to have unfavorable overall survival (OS) (HR = 2.325, 95% CI: 1.720–3.143, P < 0.001), progression-free survival (PFS) (HR = 1.917, 95% CI: 1.366–2.691, P < 0.001) and poor response to chemotherapy (OR = 0.491, 95% CI: 0.243–0.990, P = 0.047). Subgroup analyses by treatment setting, ethnicity, HR extraction, detection methods, survival analysis, and study design demonstrated that our results were robust.

Conclusions:

ERCC1 expression may be taken as an effective prognostic factor predicting the response to chemotherapy, OS, and PFS. Further studies with better study design and longer follow-up are warranted in order to gain a deeper understanding of ERCC1's prognostic value.

ERCC1 and ERCC2 as predictive biomarkers to oxaliplatin-based chemotherapy in colorectal cancer patients from Egypt

BACKGROUND

The impact of Excision repair cross-complementation group 1 (ERCC1) and group 2 (ERCC2) expression levels on the efficacy of oxaliplatin-based chemotherapy is still controversial. The present study was conducted to determine the predictive value of these molecular biomarkers in stage III and IV colorectal cancer (CRC) patients receiving oxaliplatin (OX)-based chemotherapy as first-line treatment.

METHODS

The study included 80 CRC patients who received first line oxaliplatin based chemotherapy The expression levels of ERCC1 and ERCC2-mRNA and proteins were determined in the primary tumors by quantitative real time reverse transcription polymerase chain reaction(RT-qPCR) and immunohistochemistry (IHC); respectively. The results of mRNA expression were correlated with patients' characteristics, response to treatment, overall- and event free survival (OS & EFS).

RESULTS

Sixty four out of the 80 patients were legible for assessment of ERCC1 and ERCC2 expression. The cut-off levels of ERCC1and ERCC2-RNA were 3.8×10^-3& 4.6×10^-3; respectively. Reduced ERCC1 and ERCC2 RNA expressions were detected in 50 (78.1%) and 48 (75%) cases, respectively whereas reduced proteins were detected in 48 cases (75%) for ERCC1 and ERCC2. After The median follow up period was 30.5months (range: 7-104months), Patients with low mRNAERCC1levels showed significantly longer OS (p=0.011) and EFS (p˂0.001). However, no significant relation was found between ERCC2 levels and OS or EFS. In multivariate analysis performance status (PS), stage of the disease and ERCC1-mRNA expression were independent prognostic factors for EFS whereas tumor histology and stage of the disease were independent factors for OS.

CONCLUSIONS

ERCC1 expression levels may help in selecting patients who benefit from oxaliplatin chemotherapy in stage III & IV CRC. Further large trials are needed to validate these data.

Nucleotide excision repair and response and survival to chemotherapy in colorectal cancer patients

Several new chemotherapeutic agents have become available for the treatment of colorectal cancer, which has led to increased complexity in treatment planning. Treatment decision making for individual patients could be facilitated if guided by predictive and prognostic markers. As most cytotoxic drugs induce DNA damage, the DNA damage repair pathways hold potential for yielding such biomarkers. Here, we review the current evidence of a possible involvement of the nucleotide excision repair pathway in the efficacy of chemotherapeutic agents used in the treatment of colorectal cancer. Although a large number of studies have been conducted, they are generally of moderate size and heterogeneous in design. Up to date no firm conclusions can be drawn to translate these results into the clinic. We recommend further comprehensive investigations of the nucleotide excision repair pathway in large patient studies that include both discovery and validation cohorts.

Association between mRNA expression of chemotherapy-related genes and clinicopathological features in colorectal cancer: A large-scale population analysis

To establish the individualized treatment of patients with colorectal cancer, factors associated with chemotherapeutic effects should be identified. However, to the best of our knowledge, few studies are available on this topic, although it is known that the prognosis of patients and sensitivity to chemotherapy depend on the location of the tumor and that the tumor location is important for individualized treatment. In this study, primary tumors obtained from 1,129 patients with colorectal cancer were used to measure the mRNA expression levels of the following genes associated with the effects of standard chemotherapy for colorectal cancer: 5-fluorouracil (5-FU)-related thymidylate synthase (TYMS), dihydropyrimidine dehydrogenase (DPYD) and thymidine phosphorylase (TYMP); folate-related dihydrofolate reductase (DHFR), folylpolyglutamate synthase (FPGS) and gamma-glutamyl hydrolase (GGH); irinotecan-related topoisomerase I (TOP1); oxaliplatin-related excision repair cross-complementing 1 (ERCC1); biologic agent-related vascular endothelial growth factor (VEGF) and epidermal growth factor receptor (EGFR). Large-scale population analysis was performed to determine the association of gene expression with the clinicopathological features, in particular, the location of the colorectal cancer. From the results of our analysis of the mRNA expression of these 10 genes, we noted the strongest correlation between DPYD and TYMP, followed by TYMS and DHFR. The location of the colorectal cancer was classified into 4 regions (the right- and left-sided colon, rectosigmoid and rectum) and was compared with gene expression. A significant difference in all genes, apart from VEGF, was noted. Of the remaining 9 genes, the highest expression of TYMS and DPYD was observed in the right-sided colon; the highest expression of GGH and EGFR was noted in the left-sided colon; the highest expression of DHFR, FPGS, TOP1 and ERCC1 was noted in the rectosigmoid, whereas TYMP expression was approximately equivalent in the right-sided colon and rectum, and higher than that in other locations. The data generated from this study may prove to be useful for the development of individualized chemotherapeutic treatments for patients with colorectal cancer, and will mean that the tumor location is taken into account.

Tumor-Related Molecular Mechanisms of Oxaliplatin Resistance

Oxaliplatin was the first platinum drug with proven activity against colorectal tumors, becoming a standard in the management of this malignancy. It is also considered for the treatment of pancreatic and gastric cancers. However, a major reason for treatment failure still is the existence of tumor intrinsic or acquired resistance. Consequently, it is important to understand the molecular mechanisms underlying the appearance of this phenomenon to find ways of circumventing it and to improve and optimize treatments. This review will be focused on recent discoveries about oxaliplatin tumor-related resistance mechanisms, including alterations in transport, detoxification, DNA damage response and repair, cell death (apoptotic and nonapoptotic), and epigenetic mechanisms.

The Predictive Role of ERCC1 Status in Oxaliplatin Based Neoadjuvant Therapy for Metastatic Colorectal Cancer (mCRC) to the Liver

Increased expression of excision repair cross-complementing 1 (ERCC1) in mCRC patients could be related to their response to Oxaliplatin based chemotherapy. We evaluated ERCC1 mRNA expression levels in primary bowel and liver metastases of 51 patients, and correlated with pathologic parameters and clinical outcomes. A significant negative correlation was detected between primary tumor ERCC1 and both the extent of clear surgical margins (P = 0.0011) and the percent of liver metastasis necrosis (P = 0.0167). No relationship was observed between ERCC1 expression and survival. Further study is needed to assess the promising role of ERCC1 expression as a predictive marker benefiting subgroups for Oxaliplatin.

[Prognostic values of the clinical, morphological and molecular biological characteristics of colon adenocarcinoma]

OBJECTIVE

to estimate the predictive and prognostic factors using morphological studies in patients with colon cancer to increase survival rates.

SUBJECTS AND METHODS

Immunohistochemical examination was made in 582 patients with colon adenocarcinoma, by determining 11 different indicators relating to the development of the tumor and its treatment.

RESULTS

The simultaneous determination of the chemokine receptor CXCR4 and proliferative activity (Ki-67 expression) can define disease prognosis in view of relapse-survival rates in patients with Stage II colon cancer after radical surgical treatment.

CONCLUSION

Thymidylate synthase and thymidine phosphorylase are of predictive value. The immunohistochemical examination of other markers, such as ALDH1, CCR10, ERCC-1, DYPD, topoisomerase II alpha, and class III beta-tubulin for the choice of treatment policy for patients with colon cancer has indicated that they are of no value.

Distinct gene expression profiles of proximal and distal colorectal cancer: implications for cytotoxic and targeted therapy

Colorectal cancer (CRC) is a heterogeneous disease with genetic profiles and clinical outcomes dependent on the anatomic location of the primary tumor. How location impacts the molecular makeup of a tumor and how prognostic and predictive biomarkers differ between proximal versus distal colon cancers is not well established. We investigated the associations between tumor location, KRAS and BRAF mutation status, and the mRNA expression of proteins involved in major signaling pathways, including tumor growth (EGFR), angiogenesis (VEGFR2), DNA repair (ERCC1) and fluoropyrimidine metabolism (TS). FFPE tumor specimens from 431 advanced CRC patients were analyzed. The presence of 7 different KRAS base substitutions and the BRAF V600E mutation was determined. ERCC1, TS, EGFR and VEGFR2 mRNA expression levels were detected by RT-PCR. BRAF mutations were significantly more common in the proximal colon (p<0.001), whereas KRAS mutations occurred at similar frequencies throughout the colorectum. Rectal cancers had significantly higher ERCC1 and VEGFR2 mRNA levels compared to distal and proximal colon tumors (p=0.001), and increased TS levels compared to distal colon cancers (p=0.02). Mutant KRAS status was associated with lower ERCC1, TS, EGFR, and VEGFR2 gene expression in multivariate analysis. In a subgroup analysis, this association remained significant for all genes in the proximal colon and for VEGFR2 expression in rectal cancers. The mRNA expression patterns of predictive and prognostic biomarkers as well as associations with KRAS and BRAF mutation status depend on primary tumor location. Prospective studies are warranted to confirm these findings and determine the underlying mechanisms.

Prognostic value of ERCC1 mRNA expression in non-small cell lung cancer, breast cancer, and gastric cancer in patients from Southern China

BACKGROUND

Excision repair cross complementation group 1 (ERCC1) is a nucleotide excision repair pathway gene which provides protection against platinum-based chemotherapy-induced DNA damage.

METHODS

ERCC1 mRNA expression was quantified by quantitative real-time reverse-transcription PCR in paraffin-embedded non-small cell lung cancer (NSCLC; n = 357), gastric cancer (n = 106), and breast cancer (n = 363) tissues. Survival curves were generated by Kaplan-Meier analysis; Cox proportional multivariate regression analysis was applied.

RESULTS

ERCC1 mRNA expression was significantly higher in breast cancer than gastric cancer or NSCLC (both P < 0.0001), but not significantly different in NSCLC and gastric cancer (P = 0.119). In NSCLC, the low ERCC1 group had significantly longer disease free survival (DFS) than the high ERCC1 group (29.1 vs. 21.0 months, P < 0.0001); in the surgery alone and postoperative platinum-containing chemotherapy subgroups, DFS was significantly longer for the low ERCC1 groups than high ERCC1 groups (30.2 vs. 25.1 months, P = 0.018; 27.0 vs. 19.4 months, P < 0.0001, respectively). In gastric cancer patients receiving surgery alone, the low ERCC1 group had significantly longer overall survival than the high ERCC1 group (47.54 vs. 27.47 months, P = 0.018).

CONCLUSIONS

High ERCC1 mRNA expression of the NSCLC tumor tissues was associated with poor disease-free survival (DFS), in both the surgery alone and postoperative platinum-containing chemotherapy subgroups. Meanwhile, low ERCC1 mRNA expression had significantly longer overall survival in gastric cancer patients receiving surgery alone. Therefore, ERCC1 expression was a prognostic factor and predictive marker in NSCLC, and gastric cancer after surgery alone, but was not a prognostic factor in breast cancer.

Prognostic value of biomarkers in metastatic colorectal cancer patients

BACKGROUNDS

The prognostic value of biomarkers in metastatic colorectal cancer (mCRC) patients with liver metastases remains unclear. We assessed the difference of expression of biomarkers between primary tumors and liver metastases treated with chemotherapy in mCRC patients, as well as the prognostic value of these markers.

METHODS

Forty-three mCRC patients with liver-limited disease from January 2007-November 2011 were analyzed. They all received resection of primary tumors followed by oxaliplatin-based chemotherapy. After chemotherapy, they all received hepatic resection. Forty-three paired primary and metastatic tumor specimens were collected to measure the messenger RNA expression of six biomarkers by the Danenberg tumor profile method (thymidylate synthase, dihydropyrimidine dehydrogenase [DPD], excision repair cross-complementing gene1, thymidine phosphorylase [TP], folylpolyglutamate synthase, and regenerating islet-derived family, member 4).

RESULTS

Thirty-six patients' messenger RNA was used for analysis. All markers showed similar expression between primary and metastatic sites. The low-expression group of Danenberg tumor profile and TP in the primary tumor showed significantly higher overall survival than the high-expression group (P < 0.001 and P = 0.033), but for DPD and TP in liver metastases, there were no significant differences of overall survival between the two groups. The ratios of marker expression in liver metastatic site to that in primary site of DPD and TP were significantly higher in chemo-responders than in non-chemo-responders (P = 0.034 and P = 0.022).

CONCLUSIONS

Biomarkers' expressions in liver metastases were similar to those in the primary tumor. DPD and TP in the primary lesion may be a prognostic factor in chemotherapy-naïve mCRC patients with liver-limited disease, but those in liver tumor were not. Further validated analysis to our results would be warranted.

ERCC1 polymorphisms as prognostic markers in T4 breast cancer patients treated with platinum-based chemotherapy

BACKGROUND

Polymorphisms in the excision repair cross-complimentary group 1 (ERCC1) gene have been involved in the prognosis of various cancers. In the present study, we evaluated the prognostic role of the two most common ERCC1 polymorphisms in patients with T4 breast cancer receiving platinum-based chemotherapy.

METHODS

A total of 47 patients with T4 breast cancer undergoing treatment with a platinum-based regimen were collected and followed up (median 159 months; range, 42-239 months). ERCC1 C8092A (rs3212986) and T19007C (rs11615) polymorphisms were genotyped, using an automated sequencing approach. The same series was screened for BRCA1/2 mutations by DHPLC analysis and DNA sequencing.

RESULTS

Among the tested patients, 16 (34%) and 25 (53%) presented the 8092A (homo-zygosity A/A or heterozygosity A/C) and the 19007C (homozygosity C/C or heterozygosity C/T) genotypes, respectively. The 8092A and 19007C genotypes in ERCC1 were significantly associated with overall survival in T4 breast cancer patients treated with chemotherapy containing platinum (p-values = 0.036 and 0.004, respectively). Univariate and multivariate Cox regression analyses showed that combination of 8092A and 19007C genotypes acts as a significant prognostic factor in women with T4 breast cancer receiving platinum-based chemotherapy (p-values = 0.022 and 0.049, respectively). Two (4.3%) out of 47 cases were found to carry BRCA1/2 mutations; they presented the highest overall survival rates into the series.

CONCLUSIONS

The ERCC1 8092A and 19007C genotypes or their combination may predict a favorable prognosis in T4 breast cancer patients undergoing a platinum-based treatment. Further large-scale, prospective studies are needed to validate our findings.

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.

Thymidine phosphorylase gene variant, platelet counts and survival in gastrointestinal cancer patients treated by fluoropyrimidines

The predictive value of thymidine phosphorylase gene variants (TP, also called platelet-derived endothelial cell growth factor) and thrombocytosis were controversial and worthy of further study in gastrointestinal cancer (GIC) patients. We screened all of the common missense single nucleotide polymorphisms (MAF ≥ 0.1) in fluoropyrimidines (FU) pathway genes (including TP, TS, ENOSF1 and DPD). Three of them were selected and genotyped using Sequenom MassARRAY in 141 GIC patients. TP expression was assessed by immunohistochemistry. Our aim was to evaluate the prognostic significance of studied genes and platelet counts in GIC patients. Multivariate analyses indicated in rs11479-T allele carriers, platelet counts negatively correlated to overall survival. In addition, T allele of TP: rs11479 was associated with higher TP expression in cancer tissues. We suggest TP: rs11479 variant combined with platelet counts may be useful prognostic makers in GIC patients receiving first-line FU chemotherapy and thrombopoietin factor should be used with caution in the rs11479 T allele bearing patients.

Thymidine phosphorylase expression is associated with time to progression in patients with metastatic colorectal cancer

Background

5-Fluorouracil (5-FU) is the cornerstone of chemotherapeutic treatment for patients with colorectal cancer. The enzyme thymidine phosphorylase (TP) catalyzes the conversion of 5-FU to its active metabolite, 5-fluoro-2’-deoxyuridine. TP is expressed in tumour epithelial cells and stromal cells, particularly in tumour-associated macrophages. These macrophages may affect sensitivity to chemotherapy. Previously, we identified TP as a predictive factor in microdissected tumour samples of patients with advanced colorectal cancer. In the present study, we analysed TP expression in tissues and associated stromal cells from patients with advanced colorectal cancer and associated TP levels to tumour response and time-to-event variables during first-line chemotherapy treatment. We also investigated the association between serum TP levels at the time of surgery and gene expression in primary tumour tissues.

Methods

This study included 125 patients with metastatic colorectal cancer treated with first-line 5-FU-based chemotherapy. To quantify TP gene expression levels in tumour tissues, real-time polymerase chain reaction was performed using the 7500 Fast Real-Time PCR system (Applied Biosystems, Foster City, CA, USA). TP protein concentration in matched serum samples was determined using an enzyme-linked immunosorbent assay system (USCN Life Science Inc.).

Results

The tumour response rate was 31%, and 30% of patients exhibited stable disease. No associations between TP expression level and age or gender were observed. Levels of TP mRNA in mucosa and tumours were positively correlated (r = 0.41, p < 0.01). No correlation between TP expression and tumour response rate was observed. Time to progression was significantly longer in patients with high TP expression (p < 0.01). Serum TP protein levels were not associated with tumour response or time-to-event variables and did not correlate with gene expression in tumour tissues.

Conclusions

High TP gene expression in non-microdissected tumour tissues of patients with advanced colorectal cancer correlates with longer time to progression, which could be related to treatment. These results are in contrast to previous studies where microdissected tumour cells were analysed and may be due to the presence of adjacent stromal cells. Serum TP protein expression does not correlate to TP gene expression in tissues of patients with advanced colorectal cancer.

Excision Repair Cross-Complementation group 1 (ERCC1) C118T SNP does not affect cellular response to oxaliplatin

AIMS

ERCC1 is involved in the repair of oxaliplatin-induced DNA damage. Studies for the association of the C118T SNP with clinical response to treatment with platinum drugs have rendered inconsistent results. We investigated the ERCC1 C118T SNP with respect to overall and progression-free survival in patients with advanced colorectal cancer (ACC) treated with oxaliplatin and in vitro DNA repair capacity after oxaliplatin exposure. In addition we discuss discrepancies from other studies concerning ERCC1 C118T.

MATERIALS AND METHODS

Progression-free survival was determined in 145 ACC patients treated with oxaliplatin-based chemotherapy in a phase 3 trial. For the in vitro studies regarding ERCC1 functionality, we transfected an ERCC1 negative cell line with 118C or 118T ERCC1. Cellular sensitivity and DNA repair capacity after exposure to oxaliplatin was examined by Sulphorodamine B growth inhibition assay, COMET assay and Rad51 foci staining.

RESULTS

We found no association between ERCC1 C118T and progression-free or overall survival. In addition, transfection of either 118C or 118T restores DNA-repair capacity of UV20 cells to the same level and chemosensitivity to oxaliplatin was similar in ERCC1 118C and 118T transfected cells.

CONCLUSION

This study shows that the ERCC1 C118T variants are not associated with survival in ACC patients treated with oxaliplatin or the in vitro sensitivity and DNA-repair capacity in 118C and 118T transfected cell lines. Therefore, ERCC1 C118T genotyping seems of no value in individualizing oxaliplatin based chemotherapy in ACC.

Thymidylate synthase and thymidine phosphorylase mRNA expression in primary lesions using laser capture microdissection is useful for prediction of the efficacy of FOLFOX treatment in colorectal cancer patients with liver metastasis

Chemotherapy with FOLFOX, which is a combination of 5-fluorouracil (5-FU)/leucovorin (LV) and oxaliplatin, has been used worldwide for the treatment of metastatic colorectal cancer patients. The aim of this study was to examine the candidates for predictors of the efficacy of the FOLFOX treatment regimen in colorectal cancer patients with liver metastasis, using formalin-fixed paraffin-embedded specimens. We investigated the mRNA levels of thymidylate synthase (TS), thymidine phosphorylase (TP), dihydropyrimidine dehydrogenase (DPD), orotate phosphoribosyltransferase (OPRT) and excision repair cross-complementing 1 (ERCC1) in 70 primary lesions and 30 liver metastatic lesions of colorectal cancer patients, using laser capture microdissection and real-time PCR methods. We then analyzed the correlation between their expression in primary lesions and those in corresponding liver metastatic lesions (n=30) and the relationship between their expression in the primary lesions and the efficacy of mFOLFOX6 in 45 colorectal cancer patients with unresectable liver metastasis. The gene expression in primary lesions positively correlated with those in corresponding liver metastatic lesions. The profiles of gene expression of primary lesions strongly correlated with those of synchronous liver metastatic lesions compared to that of metachronous liver metastatic lesions. TS and TP mRNA levels in the patients with complete response, partial response or stable disease (n=34) were significantly lower compared to those in the patients with progressive disease (n=11) (p=0.017 and p=0.04, respectively). Our results indicated that TS and TP mRNA expression profiles in primary lesions are sufficient to estimate the mRNA expression profiles in synchronous liver metastatic lesions compared to metachronous liver metastatic lesions. Additionally, these profiles may be useful predictors in the identification of eligible colorectal cancer patients with liver metastasis for FOLFOX treatment.

Predictive molecular classifiers in colorectal cancer

The introduction of predictive molecular markers has radically enhanced the identification of which patients may benefit from a given treatment. Despite recent controversies, KRAS mutation is currently the most recognized molecular predictive marker in colorectal cancer (CRC), predicting efficacy of anti-epidermal growth factor receptor (anti-EGFR) antibodies. However, other relevant markers have been reported and claimed to identify patients that will benefit from anti-EGFR therapies. This group of markers includes BRAF mutations, PI3KCA mutations, and loss of PTEN expression. Similarly, molecular markers for cytotoxic agents' efficacy also may predict outcome in patients with CRC. This review aims to summarize the most important predictive molecular classifiers in patients with CRC and further discuss any inconsistent or conflicting findings for these molecular classifiers.

TS and ERCC-1 mRNA expressions and clinical outcome in patients with metastatic colon cancer in CONFIRM-1 and -2 clinical trials

To validate established cutoff levels of thymidylate synthase (TS) and excision repair cross-complementing (ERCC-1) intratumoral mRNA expressions in tumor samples from metastatic colorectal cancer (mCRC) patients treated with PTK787/ZK222584 (PTK/ZK). From 122 samples of patients with mCRC enrolled in CONFIRM-1 (Colorectal Oral Novel Therapy for the Inhibition of Angiogenesis and Retarding of Metastases) or CONFIRM-2, mRNA was isolated of microdissected formalin-fixed paraffin-embedded samples and quantitated using TaqMan-based technology. Existing TS and ERCC-1 cutoff levels were tested for their prognostic value in first-line and second-line therapy. TS expression was associated with overall survival (OS) in first-line, but not second-line therapy. ERCC-1 was associated with OS in patients treated with first-line and second-line FOLFOX4. In first-line FOLFOX4, combination of high TS and/or high ERCC-1 was associated with shorter OS. A correlation was observed between ERCC-1 expression and benefit from PTK/ZK+FOLFOX4 treatment. TS and ERCC-1 expression is associated with clinical outcome in mCRC. Baseline TS and ERCC-1 levels may allow the selection of patients who benefit from FOLFOX4 chemotherapy.

Thymidine Phosphorylase/β-tubulin III expressions predict the response in Chinese advanced gastric cancer patients receiving first-line capecitabine plus paclitaxel

BACKGROUND

To assess the role of Thymidine Phosphorylase and β-tubulin III in clinical outcome of Chinese advanced gastric cancer patients receiving first-line capecitabine plus paclitaxel.

METHODS

The clinical data and tumor biopsies prior treatment from 33 advanced gastric cancer patients receiving capecitabine plus paclitaxel (cohort 1, experimental group) and 18 patients receiving capecitabine plus cisplatin (cohort 2, control group) in Beijing Cancer Hospital from July 2003 to December 2008 were retrospectively collected and analyzed for Thymidine Phosphorylase and β-tubulin III expressions by immunohistochemistry. The relationships between expressions of biomarkers and response or survival were determined by statistical analysis.

RESULTS

The median age of 51 patients was 57 years (range, 27-75) with male 34 and female 17, and the response rate, median progression-free survival and overall survival were 43.1%, 120d and 265d. Among cohort 1, the response rate, median progression-free survival and overall survival in β-tubulin III positive (n = 22) and negative patients (n = 11) were 36.4%/72.7% (positive vs negative, P = 0.049), 86d/237d (P = 0.046) and 201d/388d (P = 0.029), respectively; the response rate (87.5% vs 14.3%, P = 0.01) and median progression-free survival (251d vs 84d, P = 0.003) in Thymidine Phosphorylase positive & β-tubulin III negative patients (n = 8) were also significantly higher than those in Thymidine Phosphorylase negative & β-tubulin III positive patients (n = 7). There was no correlation between β-tubulin III expression and response or survival among cohort 2 (n = 18).

CONCLUSIONS

In Chinese advanced gastric cancer, Thymidine Phosphorylase positive & β-tubulin III negative might predict response and prognosis to capecitabine plus paclitaxel chemotherapy. Further prospective evaluation in large samples should be performed to confirm these preliminary findings.

A review of excision repair cross-complementation group 1 in colorectal cancer

Oxaliplatin-based chemotherapy is the standard of care in patients with high-risk stage II and stage III colorectal cancer as well as in patients with advanced disease. Unfortunately, a large proportion of patients offered oxaliplatin fail to benefit from it. In the era of personalized treatment, there are strong efforts to identify biomarkers that will predict efficacy to oxaliplatin-based treatments. Excision repair cross-complementation group 1 (ERCC1) is a key element in the nucleotide excision repair (NER) pathway, which is responsible for repairing DNA adducts induced by platinum compounds. ERCC1 has recently been shown to be closely associated with outcome in patients with non-small-cell lung cancer (NSCLC): both high ERCC1 protein and gene expression are associated with resistance to cisplatin-based chemotherapy and better outcome without treatment. Therefore, ERCC1 has the potential to be used as a strong candidate biomarker, both predictive and prognostic, for colorectal cancer. This review will focus on the preclinical and clinical evidences supporting ERCC1 as a major molecule in oxaliplatin resistance. In addition, the important technologies used to assess ERCC1 gene and protein expression will be highlighted.

Low thymidylate synthase, thymidine phosphorylase, and dihydropyrimidine dehydrogenase mRNA expression correlate with prolonged survival in resected non-small-cell lung cancer

BACKGROUND

Thymidylate synthase (TS), thymidine phosphorylase (TP), and dihydropyrimidine dehydrogenase (DPD) are key enzymes in the 5-fluorouracil (5-FU) pathway. The aim of this study was to investigate the mRNA expression of TS, TP, and DPD in tumor and nontumor lung tissue of patients with NSCLC and to determine the potential of these genes as molecular biomarkers.

MATERIALS AND METHODS

The TS, TP, and DPD mRNA expression was analyzed in tumor and nontumor tissue of 91 patients with NSCLC by quantitative real-time reverse-transcriptase polymerase chain reaction (RT-PCR) with β-actin as the internal control. All tumors were R0 resected. The median follow-up was 85.9 months.

RESULTS

The mRNA expression of TS, TP, and DPD was detectable in both tumor and nontumor tissue. Tumor TP (tTP) seems to correlate with tumor TS (tTS) and tumor DPD (tDPD) mRNA expression, but no correlation in the mRNA expression of tTS and tDPD was found. The TS and TP mRNA expression levels were significantly associated with patient prognosis. The 5-year survival probability was 58.7% (TS), and 59.6% (TP) for patients with a low TS and TP mRNA expression and 33.4% (TS), and 31.8% (TP) for patients with a high mRNA expression (P = .04 [TS]; P = .03 [TP]; log-rank). The probability of survival was significantly different among patients with no and any 1 highly expressed gene compared with patients with any 2 or more of the 3 investigated genes highly expressed (P = .012).

CONCLUSION

High TS, TP, and DPD mRNA expression are biomarkers for a more severe malign NSCLC biology. Quantitation of the mRNA expression of these genes seems to be helpful in differing patients with unequal malign tumor entities and therefore possibly helpful in selecting tailored additional therapies to control the disease.

Advances in identifying predictive markers for response to fluoropyrimidine-based chemotherapy for colorectal cancer

Selection of high-efficacy and low-toxicity drugs is key to improving the efficacy of chemotherapy for solid tumors. Because of tumor heterogeneity and ethnic/individual differences, the efficiency and toxicity of chemotherapy drugs vary across individuals. Since standard chemotherapy regimens developed based on population data can not completely meet clinical needs, increasing attention has been directed towards individualized chemotherapy based on drug genetics and/or genomics testing. In this paper, we review the advances in identifying predictive markers for response to fluoropyrimidine-based chemotherapy for colorectal cancer.

Three-gene predictor of clinical outcome for gastric cancer patients treated with chemotherapy

To identify transcriptional profiles predictive of the clinical benefit of cisplatin and fluorouracil (CF) chemotherapy to gastric cancer patients, endoscopic biopsy samples from 96 CF-treated metastatic gastric cancer patients were prospectively collected before therapy and analyzed using high-throughput transcriptional profiling and array comparative genomic hybridization. Transcriptional profiling identified 917 genes that are correlated with poor patient survival after CF at P<0.05 (poor prognosis signature), in which protein synthesis and DNA replication/recombination/repair functional categories are enriched. A survival risk predictor was then constructed using genes, which are included in the poor prognosis signature and are contained within identified genomic amplicons. The combined expression of three genes—MYC, EGFR and FGFR2—was an independent predictor for overall survival of 27 CF-treated patients in the validation set (adjusted P=0.017), and also for survival of 40 chemotherapy-treated gastric cancer patients in a published data set (adjusted P=0.026). Thus, combined expression of MYC, EGFR and FGFR2 is predictive of poor survival in CF-treated metastatic gastric cancer patients.

Comparison of thymidine phosphorylase expression and prognostic factors in gallbladder and bile duct cancer

BACKGROUND

Biliary tract cancers have limitations in information about different location-related pathogenesis and clinico-pathological characteristics. The goal of this study was to investigate anatomical site-related similarities and differences in biliary tract cancers and to assess the expression and clinical significance of functional proteins such as p53, cyclin D1, survivin, thymidine phosphorylase, and ERCC1.

METHODS

One hundred and sixty-one patients with biliary tract adenocarcinomas, who underwent curative or palliative surgery in a single institution between October 1994 and December 2003 were evaluated, retrospectively. The level of protein expression of p53, cyclin D1, survivin, thymidine phosphorylase, and ERCC1 was assessed by immunohistochemistry.

RESULTS

With respect to clinico-pathological characteristics, gallbladder cancer was more frequent in women, and bile duct cancer was more common in men. Perineural invasion was more common in bile duct cancer. Recurrence as a distant metastasis was more common in gallbladder cancer. Immunohistochemical analysis revealed that thymidine phosphorylase expression was significantly higher in gallbladder cancer than in bile duct cancer. Positive thymidine phosphorylase and p53 staining were associated with an advanced stage. Differentiation, vascular invasion, perineural invasion, lymphatic invasion, lymph node metastasis, and TNM stage independently predicted poor prognosis in biliary tract cancer. These correlations were seen more clearly in gallbladder cancer. The immunohistochemical staining patterns of p53, cyclin D1, survivin, thymidine phosphorylase, and ERCC1 showed no prognostic significance in biliary tract cancers.

CONCLUSIONS

We concluded that gallbladder and bile duct cancers are considered to be separate diseases with different clinico-pathological characteristics and prognostic factors. In addition, we hypothesize that high expression of thymidine phosphorylase by gallbladder cancer results in a higher response rate to capecitabine by gallbladder cancer than bile duct cancer.

The predictive value of genetic variations in the vascular endothelial growth factor A gene in metastatic colorectal cancer

Single-nucleotide polymorphisms (SNPs) in the vascular endothelial growth factor A (VEGF-A) gene may have clinical implications. The aim of this study was to investigate the possible predictive value of the VEGF-A SNPs, in patients with metastatic colorectal cancer (mCRC) treated with first-line capecitabine and oxaliplatin (XELOX). The study included 72 patients with mCRC. Genomic DNA was isolated from whole blood, and SNPs were analyzed by PCR. SNPs were correlated with response and progression-free survival (PFS). Haplotypes were estimated using the PHASE program. Response was observed in 21% of the patients with the -2578 CA genotype compared with 59% of the patients with CC+AA, P=0.002, in 26% of the patients with the -460 CT genotype compared with 57% with CC+TT, P=0.01, and in 27% of the patients with the +405 GC genotype compared with 54% with GG+CC, P=0.02. Two SNPs were significantly related to PFS. A haplotype with a significant relationship to response was identified. The results demonstrated obvious relationships between genetic variations in the VEGF-A gene and response to first-line XELOX in patients with mCRC, which translated to a significant difference in PFS. The results call for validation in a larger cohort of patients.

Clinical significance of the expression of multidrug resistance gene products in colorectal carcinoma

AIM: To detect the expression of multidrug resistance gene product in colorectal carcinoma (CRC) and analyze their significance in the chemotherapy for CRC.

METHODS: Fifty-six CRC patients who underwent radical surgery from May 2007 to May 2009 at our hospital were randomly selected. Ten healthy subjects who underwent colonoscopy and biopsy were randomly selected as controls. The streptavidin-peroxidase (SP) immunohistochemistry was used to detect the expression of GST-π, P-gp, Topo-II, TS and MRP in CRC tissues and normal mucosal tissues. The clinicopathological data of the patients were analysed retrospectively.

RESULTS: The expression of GST-π, P-gp, Topo-II, TS and MRP proteins showed significant differences between CRC patients and control patients (all P < 0.01 or 0.05). The positive expression rates of GST-π, P-gp, Topo-II, TS and MRP proteins in CRC were 73.2% (41/56), 66.1% (37/56), 48.2% (27/56), 41.1% (23/56) and 37.5% (21/56), respectively. The positive expression rates of these proteins were closely correlated with histological type and degree of differentiation, but not correlated with patient sex, age, tumors site, tumor size, invasive depth and lymph node metastasis.

CONCLUSION: The expression of GST-π, P-gp, Topo-II, TS and MRP proteins in CRC shows obvious heterogeneity. The overexpression of these protein underlies the multidrug resistance in CRC.