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

Optimizing Adjuvant Therapy after Surgery for Colorectal Cancer Liver Metastases: A Systematic Review

The liver is the most common site of colorectal cancer metastatic spread. Although metastasectomy is the gold standard for fit patients with resectable colorectal cancer liver metastases (CRLMs), their management after surgical treatment remains controversial. The objective of this systematic review was to collate the currently available data of the agents used in the adjuvant setting in order to define the most optimal therapeutic strategy. A systematic review of the literature was conducted by searching PubMed/Medline and Cochrane library databases. We included studies that evaluated the efficacy, the tolerability and the safety profile of various chemotherapeutic agents that are used as adjuvant treatment after surgical resection of CRLMs. The outcomes of interest were regression-free survival (RFS), disease-free survival (DFS), overall survival (OS) and severe toxicities. From 543 initial articles, 29 publications with 7028 patients were finally included. In general, the results of the eligible studies indicated that adjuvant therapy after resection of CRLMs led to improved RFS/DFS rates, but this benefit did not contribute to a statistically significant prolongation of OS. Moreover, the choice of the therapeutic strategy, namely systematic or regional chemotherapy or the combination of both, did not seem to have a differential impact on patient outcomes. However, these results should be interpreted with caution since the majority of the chosen studies are of low or moderate quality. In this context, further high-quality clinical trials conducted on patient sub-populations with modern therapies are required in order to reduce in-study and between-study heterogeneity and determine which patients are expected to derive the maximum benefit from adjuvant therapy after surgery for CRLMs.

Modern Approaches to Testing Drug Sensitivity of Patients' Tumors (Review)

Drug therapy is still one of the basic techniques used to treat cancers of different etiology. However, tumor resistance to drugs is a pressing problem limiting drug treatment efficacy. It is obvious for both modern fundamental and clinical oncology that there is the need for an individual approach to treating cancer taking into account the biological properties of a tumor when prescribing chemo- and targeted therapy. One of the promising strategies is to increase the antitumor therapy efficacy by developing predictive tests, which enable to evaluate the sensitivity of a particular tumor to a specific drug or a drug combination before the treatment initiation and, thus, make individual therapy selection possible.

The present review considers the main approaches to drug sensitivity assessment of patients’ tumors: molecular genetic profiling of tumor cells, and direct efficiency testing of the drugs on tumor cells isolated from surgical or biopsy material. There were analyzed the key directions in research and clinical studies such as: the search for predictive molecular markers, the development of methods to maintain tumor cells or tissue sections viable, i.e. in a condition maximum close to their physiological state, the development of high throughput systems to assess therapy efficiency. Special attention was given to a patient-centered approach to drug therapy in colorectal cancer.

HIF-1α expression in liver metastasis but not primary colorectal cancer is associated with prognosis of patients with colorectal liver metastasis

Background

The role of hypoxia-inducible factor-1α (HIF-1α) in primary colorectal cancer (CRC) and colorectal liver metastasis (CRLM) has remained unclear. The aim of this study was to investigate HIF-1α expression and its association with prognosis in patients with CRLM with a focus on hepatic stellate cells (HSCs).

Methods

Colon cancer cells were cultured in HSC-conditioned medium (CM), and HIF-1α expression and cell migration were analyzed. Seventy-five patients with CRLM who underwent an initial curative hepatectomy were enrolled. We examined HIF-1α expressions and patient prognosis between primary CRCs and the matched liver metastatic specimens.

Results

Activated HSCs induced HIF-1α mRNA and protein expression in colon cancer cells (p < 0.01) and promoted cell migration (p < 0.01). The positive rates of HIF-1α expression in primary CRCs and liver metastases were 68.0 and 72.0%, respectively. There were no differences in overall (OS) and disease-free survival (DFS) of HIF-1α expression in primary CRC. However, HIF-1α expression in liver metastasis correlated to poor prognosis in both OS and DFS. Furthermore, patients with HIF-1α positive expression in liver metastasis had poor prognosis.

Conclusion

HIF-1α expression in liver metastasis determines poor prognosis of CRLM patients. HSCs might play a key role in aggressive phenotypes of tumor cells.

Angiogenesis in primary colorectal cancer and matched metastatic tissues: Biological and clinical implications for anti-angiogenic therapies

Metastasis remains a notable issue in patients with newly diagnosed colorectal carcinomas (CRC). Although anti-angiogenic therapies target metastatic diseases, hypoxia-inducible factor-1 α (HIF-1α) and vascular endothelial growth factor (VEGF) status are routinely evaluated in primary tumors as metastatic sites are infrequently biopsied. The present study aimed to investigate the expression and significance of HIF-1α, VEGF and microvascular density (MVD) in primary tumors and corresponding metastatic CRC tissues. HIF-1α, VEGF and CD34 status were analyzed via immunohistochemistry analysis in 46 patients who underwent surgical resection of primary CRC (35 colon and 11 rectum) and matched metastases (lymph node and liver metastases) in Shandong Cancer Hospital. The association between selected biomarker status and clinicopathological characteristics was analyzed, and expression levels in primary tumors and corresponding metastases were compared. A total of 46 paired colorectal primary tumor and synchronous metastases samples were acquired for analysis using a standardized HIF-1α, VEGF and CD34 immunohistochemical procedure. The results demonstrated that the positive rates of HIF-1α and VEGF in primary CRC were 70 and 73.9%, respectively. HIF-1α (60.9%) and VEGF (58.7%) expression decreased in the lymph metastatic samples compared with primary CRC. Conversely, the level of MVD in primary tumors was significantly higher compared with metastatic tumors. No significant differences were demonstrated between HIF-1α and VEGF expression and the different clinicopathological features in primary CRC and corresponding metastases. Primary carcinomas and matched metastatic tissues demonstrated a moderate level of consistent immunoreactivity for HIF-1α and VEGF. HIF-1α, VEGF and CD34 were expressed in both primary tumors and corresponding metastases of CRC, suggesting that they may be involved in the development of metastasis. HIF-1α and VEGF expression in primary sites was consistent with that observed in metastases; however, it varied from that exhibited in MVD. The current analysis will improve the current understanding of the metastasis models and provide further evidence for evaluating the response to HIF-1α and VEGF inhibitors.

Relationship between folate concentration and expression of folate-associated genes in tissue and plasma after intraoperative administration of leucovorin in patients with colorectal cancer

Purpose

The aim of study was to investigate the relationship between folate concentration and expression of folate-associated genes in tumour, mucosa and plasma of patients with colorectal cancer, after intraoperative administration of bolus leucovorin (LV).

Methods

Eighty patients were randomized into four groups to receive 0, 60, 200, or 500 mg/m² LV, respectively. Tissue and plasma folate concentrations were assessed by LC–MS/MS. Gene expression of ABCC3/MRP3, FPGS, GGH, MTHFD1L, SLC46A1/PCFT, and SLC19A1/RFC-1 was determined using quantitative PCR.

Results

The folate concentration in tumour increased with increasing dosage of LV. Half of the patients treated with 60 mg/m² did not reach a level above the levels of untreated patients. A significant correlation between folate concentration in tumour and mucosa was found in untreated patients, and in the group treated with 60 mg/m² LV. The 5-MTHF/LV ratio correlated negatively with folate concentration in mucosa, whereas a positive correlation was found in tumour of patients who received 200 or 500 mg/m² LV. A positive correlation was found between folate concentration and expression of all genes, except MTHFD1L, in patients who received LV. There was a negative correlation between 5-MTHF concentration in plasma of untreated patients and expression of GGH and SLC46A1/PCFT in tumour.

Conclusions

The results indicate the possibility of using the individual plasma 5-MTHF/LV ratio after LV injection as a surrogate marker for tissue folate concentration. Expression of several folate-associated genes is associated with folate concentration in tissue and plasma and may become useful when predicting response to LV treatment.

Electronic supplementary material

The online version of this article (10.1007/s00280-018-3690-9) contains supplementary material, which is available to authorized users.

Development of an Experimental Model for Analyzing Drug Resistance in Colorectal Cancer

Colorectal cancer (CRC) is one of the most common cancers, for which combination treatment of chemotherapy is employed. However, most patients develop drug resistance during the course of treatment. To clarify the mechanisms of drug resistance, various research models have been developed. Recently, we established a human CRC patients-derived three-dimensional (3D) culture system using an air-liquid interface organoid method. It contained numerous cancer stem cells and showed resistance to 5-fluorouracil and Irinotecan. In this review, we introduce conventional and our established models for studying drug resistance in CRC.

Significance of Notch and Wnt signaling for chemoresistance of colorectal cancer cells HCT116

5-fluorouracil (5-FU) and oxaliplatin (OxaPt) are the main chemotherapeutics for colorectal cancer (CRC). Chemotherapy response rates for advanced CRC remain low, primarily due to intrinsic or acquired chemoresistance. The importance of Notch and Wnt signaling for carcinogenesis of CRC as well as crosstalk of Notch and Wnt signaling with many oncogenic signaling pathways suggest that Notch and Wnt pathways could be responsible for chemoresistance. In this study, we compared changes in Notch and Wnt signaling after 5-FU and OxaPt treatment in CRC cells HCT116 and its chemoresistant sublines HCT116/FU and HCT116/OXA. The levels of Notch1 receptor intracellular domain NICD1 and non-phosphorylated β-catenin, the reporters of Notch and Wnt signaling, were upregulated in untreated chemoresistant HCT116/FU and HCT116/OXA cells. Our data suggest that Notch inhibitor RO4929097 (RO) and Wnt inhibitor XAV939 (XAV) enhance the survival potential of OxaPt-treated cells. The protein level of Notch target gene HES1 was significantly upregulated in chemoresistant HCT116/FU and HCT116/OXA cells, compared to HCT116. HES1 silencing increased viability of HCT116 and its chemoresistant sublines after 5-FU or OxaPt treatment. The results of HES1 downregulation coincide with RO and XAV effects on cell viability of OxaPt-treated cells.

Prediction of novel target genes and pathways involved in irinotecan-resistant colorectal cancer

Background

Acquired drug resistance to the chemotherapeutic drug irinotecan (the active metabolite of which is SN-38) is one of the significant obstacles in the treatment of advanced colorectal cancer (CRC). The molecular mechanism or targets mediating irinotecan resistance are still unclear. It is urgent to find the irinotecan response biomarkers to improve CRC patients’ therapy.

Methods

Genetic Omnibus Database GSE42387 which contained the gene expression profiles of parental and irinotecan-resistant HCT-116 cell lines was used. Differentially expressed genes (DEGs) between parental and irinotecan-resistant cells, protein-protein interactions (PPIs), gene ontologies (GOs) and pathway analysis were performed to identify the overall biological changes. The most common DEGs in the PPIs, GOs and pathways were identified and were validated clinically by their ability to predict overall survival and disease free survival. The gene-gene expression correlation and gene-resistance correlation was also evaluated in CRC patients using The Cancer Genomic Atlas data (TCGA).

Results

The 135 DEGs were identified of which 36 were upregulated and 99 were down regulated. After mapping the PPI networks, the GOs and the pathways, nine genes (GNAS, PRKACB, MECOM, PLA2G4C, BMP6, BDNF, DLG4, FGF2 and FGF9) were found to be commonly enriched. Signal transduction was the most significant GO and MAPK pathway was the most significant pathway. The five genes (FGF2, FGF9, PRKACB, MECOM and PLA2G4C) in the MAPK pathway were all contained in the signal transduction and the levels of those genes were upregulated. The FGF2, FGF9 and MECOM expression were highly associated with CRC patients’ survival rate but not PRKACB and PLA2G4C. In addition, FGF9 was also associated with irinotecan resistance and poor disease free survival. FGF2, FGF9 and PRKACB were positively correlated with each other while MECOM correlated positively with FGF9 and PLA2G4C, and correlated negatively with FGF2 and PRKACB after doing gene-gene expression correlation.

Conclusion

Targeting the MAPK signal transduction pathway through the targeting of the FGF2, FGF9, MECOM, PLA2G4C and PRKACB might increase tumor responsiveness to irinotecan treatment.

Effect of ethanol extract of HPRS, a Traditional Chinese Medicine formula, on HCT116 cell Line

OBJECTIVE

In this study, we investigated the effects of ethanol extract of Hupiruisu Fang (HPRS), a formula of Traditional Chinese Medicine, on HCT116 cell line.

METHODS

MKN45, A549, Hela and HCT116 cells were treated with ethanol extract of HPRS alone or the extract plus 5-Fluorouracil (5-FU) for 48 h, and then the cell viabilities were measured using CCK-8 Kit. The early apoptosis rate and total apoptosis rate in both HCT116 cells were evaluated by flow cytometry. The mRNA levels of apoptosis-related genes including caspase-3, caspase-8, Bcl2 and Bax were detected by real-time quantitative polymerase chain reaction. Lastly, the protein activities and expressions of those apoptosis related genes were observed for further verifying the pro-apoptosis of the extract of HPRS.

RESULTS

Ethanol extract of HPRS could significantly induce apoptosis in HCT116 cell line. Synergistic analysis revealed that the extract exhibited a significant effect upon 5-FU-associated cytotoxicity in the cell line.

CONCLUSION

The ethanol extract of HPRS plus 5-FU might have the potential to improve the treatment of colorectal cancer.

Cell Line Derived 5-FU and Irinotecan Drug-Sensitivity Profiles Evaluated in Adjuvant Colon Cancer Trial Data

PURPOSE

This study evaluates whether gene signatures for chemosensitivity for irinotecan and 5-fluorouracil (5-FU) derived from in vitro grown cancer cell lines can predict clinical sensitivity to these drugs.

METHODS

To test if an irinotecan signature and a SN-38 signature could identify patients who benefitted from the addition of irinotecan to 5-FU, we used gene expression profiles based on cell lines and clinical tumor material. These profiles were applied to expression data obtained from pretreatment formalin fixed paraffin embedded (FFPE) tumor tissue from 636 stage III colon cancer patients enrolled in the PETACC-3 prospective randomized clinical trial. A 5-FU profile developed similarly was assessed by comparing the PETACC-3 cohort with a cohort of 359 stage II colon cancer patients who underwent surgery but received no adjuvant therapy.

RESULTS

There was no statistically significant association between the irinotecan or SN-38 profiles and benefit from irinotecan. The 5-FU sensitivity profile showed a statistically significant association with relapse free survival (RFS) (hazard ratio (HR) = 0.54 (0.41-0.71), p<1e-05) and overall survival (HR = 0.47 (0.34-0.63), p<1e-06) in the PETACC-3 subpopulation. The effect of the 5-FU profile remained significant in a multivariable Cox Proportional Hazards model, adjusting for several relevant clinicopathological parameters. No statistically significant effect of the 5-FU profile was observed in the untreated cohort of 359 patients (relapse free survival, p = 0.671).

CONCLUSION

The irinotecan predictor had no predictive value. The 5-FU predictor was prognostic in stage III patients in PETACC-3 but not in stage II patients with no adjuvant therapy. This suggests a potential predictive ability of the 5-FU sensitivity profile to identify colon cancer patients who may benefit from 5-FU, however, any biomarker predicting benefit for adjuvant 5-FU must be rigorously evaluated in independent cohorts. Given differences between the two study cohorts, the present results should be further validated.

Characterization of DNA topoisomerase I in three SN-38 resistant human colon cancer cell lines reveals a new pair of resistance-associated mutations

BACKGROUND

DNA topoisomerase I (Top1) is a DNA unwinding protein and the specific target of the camptothecin class of chemotherapeutic drugs. One of these, irinotecan, acting through its active metabolite SN-38, is used in the treatment of metastatic colorectal cancer. However, resistance to irinotecan represents a major clinical problem. Since molecular alterations in Top1 may result in resistance to irinotecan, we characterized Top1 in three human colon cancer cell lines with acquired resistance to SN-38.

METHODS

Three SN-38 resistant (20-67 fold increased resistance) cell lines were generated and compared to wild-type parental cells with regards to: TOP1 gene copy number and gene sequence, Top1 expression (mRNA and protein), Top1 enzymatic activity in the absence and presence of drug, and Top1-DNA cleavage complexes in drug treated cells. TOP1 mutations were validated by PCR using mutant specific primers. Furthermore, cross-resistance to two indenoisoquinoline Top1-targeting drugs (NSC 725776 and NSC 743400) and two Top2-targeting drugs (epirubicin and etoposide) was investigated.

RESULTS

Two of three SN-38 resistant cell lines carried TOP1 gene copy number aberrations: A TOP1 gene copy gain and a loss of chromosome 20, respectively. One resistant cell line harbored a pair of yet unreported TOP1 mutations (R364K and G717R) in close proximity to the drug binding site. Mutant TOP1 was expressed at a markedly higher level than wild-type TOP1. None or very small reductions were observed in Top1 expression or Top1 activity in the absence of drug. In all three SN-38 resistant cell lines Top1 activity was maintained in the presence of high concentrations of SN-38. None or only partial cross-resistance were observed for etoposide and epirubicin, respectively. SN-38 resistant cells with wild-type TOP1 remained sensitive to NSC 743400, while cells with mutant TOP1 was fully cross-resistant to both indenoisoquinolines. Top1-DNA cleavage complex formation following drug treatment supported the other findings.

CONCLUSIONS

This study adds to the growing knowledge about resistance mechanisms for Top1-targeting chemotherapeutic drugs. Importantly, two yet unreported TOP1 mutations were identified, and it was underlined that cross-resistance to the new indenoisoquinoline drugs depends on the specific underlying molecular mechanism of resistance to SN-38.

Multiplexed Dosing Assays by Digitally Definable Hydrogel Volumes

Stable and low-cost multiplexed drug sensitivity assays using small volumes of cells or tissue are in demand for personalized medicine, including patient-specific combination chemotherapy. Spatially defined projected light photopolymerization of hydrogels with embedded active compounds is introduced as a flexible and cost-efficient method for producing multiplexed dosing assays. The high spatial resolution of light projector technology defines multiple compound doses by the volume of individual compound-embedded hydrogel segments. Quantitative dosing of multiple proteins with a dynamic range of 1-2 orders of magnitude is demonstrated using fluorescently labeled albumins. The hydrogel matrix results from photopolymerization of low-cost poly(ethylene glycol) diacrylates (PEGDA), and tuning of the PEGDA composition enables fast complete dosing of all tested species. Dosing of hydrophilic and hydrophobic compounds is demonstrated using two first-line chemotherapy regimens combining oxaliplatin, SN-38, 5-fluorouracil, and folinic acid, with each compound being dosed from a separate light-defined hydrogel segment. Cytotoxicity studies using a colorectal cancer cell line show equivalent effects of dissolved and released compounds. Further control of the dosing process is demonstrated by liposomal encapsulation of oxaliplatin, stable embedding of the liposomes in hydrogels for more than 3 months, and heat-triggered complete release of the loaded oxaliplatin.

Establishment and characterization of models of chemotherapy resistance in colorectal cancer: Towards a predictive signature of chemoresistance

Current standard treatments for metastatic colorectal cancer (CRC) are based on combination regimens with one of the two chemotherapeutic drugs, irinotecan or oxaliplatin. However, drug resistance frequently limits the clinical efficacy of these therapies. In order to gain new insights into mechanisms associated with chemoresistance, and departing from three distinct CRC cell models, we generated a panel of human colorectal cancer cell lines with acquired resistance to either oxaliplatin or irinotecan. We characterized the resistant cell line variants with regards to their drug resistance profile and transcriptome, and matched our results with datasets generated from relevant clinical material to derive putative resistance biomarkers. We found that the chemoresistant cell line variants had distinctive irinotecan- or oxaliplatin-specific resistance profiles, with non-reciprocal cross-resistance. Furthermore, we could identify several new, as well as some previously described, drug resistance-associated genes for each resistant cell line variant. Each chemoresistant cell line variant acquired a unique set of changes that may represent distinct functional subtypes of chemotherapy resistance. In addition, and given the potential implications for selection of subsequent treatment, we also performed an exploratory analysis, in relevant patient cohorts, of the predictive value of each of the specific genes identified in our cellular models.

Gene expression differences in primary colorectal tumors and matched liver metastases: chemotherapy related or tumoral heterogeneity?

BACKGROUND

Treatment of metastatic colorectal cancer (mCRC) is generally based on genetic testing performed in primary tumor biopsies, but whether the genomic status of primary tumors is identical to that of metastases is not well known. We compared the gene expression profiles of formalin-fixed paraffin-embedded (FFPE) biopsies of colorectal primary tumors and matched liver metastases.

PATIENTS AND METHODS

We compared the expression of 18 genes in FFPE CRC tumors and their matched liver metastases from 32 patients. The expression of each gene in CRC primary tumors and their matched liver metastases was tested using Student's t test for paired samples. Pairwise correlations of each gene in the primary tumors and matched liver metastases were evaluated by Pearson's correlation coefficient.

RESULTS

The expression of six genes was significantly different in primary tumors compared with their matched liver metastases [CXCR4 (p < 0.001), THBS1 (p = 0.007), MMP 9 (p = 0.048), GST Pi (p = 0.050), TYMP (p = 0.042) and DPYD (p < 0.001)]. For the remaining genes, where no significant differences were observed, only SMAD4 (r s = 0.447, p = 0.010), ERCC1 (r s = 0.423, p = 0.016) and VEGF A (r s = 0.453, p = 0.009) showed significant correlation in expression between the two tissues. Therefore, we only detected similar gene expression levels between the tumor and the metastases in these three markers.

CONCLUSIONS

We only found similar gene expression levels between the tumor and the metastases in three genes (SMAD4, ERCC1, and VEGF A). However, our study could not assess whether the differences in gene expression were secondary to tumoral heterogeneity or to molecular changes induced by previous chemotherapy.

Gene signatures of drug resistance predict patient survival in colorectal cancer

Different combinations of 5-fluorouracil (5-FU), oxaliplatin, irinotecan and other newly developed agents have been used to treat colorectal cancer. Despite the advent of new treatment regimens, the 5-year survival rate for metastatic colorectal cancer remains low (~10%). Knowing the drug sensitivity of a given tumor for a particular agent could significantly impact decision making and treatment planning. Biomarkers are proven to be successful in characterizing patients into different response groups. Using survival prediction analysis, we have identified three independent gene signatures, which are associated with sensitivity of colorectal cancer cells to 5-FU, oxaliplatin or irinotecan. On the basis of the three gene signatures, three score systems were developed to stratify patients from sensitive to resistance. These score systems exhibited robustness in stratify patients in two independent clinical studies. Patients with high scores in all three drugs exhibited the lowest survival.

Assessment of the topoisomerase I gene copy number as a predictive biomarker of objective response to irinotecan in metastatic colorectal cancer

OBJECTIVE

DNA topoisomerase I is a putative biomarker of irinotecan efficacy with clinical associations previously demonstrated at the protein level. The purpose of the present study was to perform the first clinical investigation of the association between the DNA topoisomerase I gene (TOP1) copy number and objective response following irinotecan treatment in patients with metastatic colorectal cancer.

MATERIALS AND METHODS

Formalin-fixed, paraffin-embedded tumor samples from 78 patients, who received irinotecan monotherapy in second line, were included. TOP1 was assessed by fluorescence in situ hybridization using a technically validated dual-probe combination that hybridizes to TOP1, located at 20q12-q13.1, and to the centromere region of chromosome 20 (CEN-20). In univariate logistic regression models, the TOP1 signal count per cell and the TOP1/CEN-20 ratio were associated with objective response, which was evaluated according to RECIST v.1.1.

RESULTS

Gain of TOP1 was identified in 52.6% and 37.2% using the following cutoff values: TOP1 signal count per cell ≥3.6 and TOP1/CEN-20 ≥1.5, respectively. A borderline significant association (Odds ratio (OR): 1.62; p = 0.07) between a stepwise increase in the TOP1 signal count and objective response was demonstrated. In relation to the applied cutoff values, nonsignificant associations with objective response were identified for the TOP1 signal count (OR: 2.41; p = 0.23) and for the TOP1/CEN-20 ratio (OR: 2.05; p = 0.30).

CONCLUSIONS

Despite limitations of the study the positive associations between TOP1 and objective response suggest that further analysis in larger tumor material, preferably in a randomized setting, is highly warranted.

Validation of the 12-gene colon cancer recurrence score in NSABP C-07 as a predictor of recurrence in patients with stage II and III colon cancer treated with fluorouracil and leucovorin (FU/LV) and FU/LV plus oxaliplatin

PURPOSE

Accurate assessments of recurrence risk and absolute treatment benefit are needed to inform colon cancer adjuvant therapy. The 12-gene Recurrence Score assay has been validated in patients with stage II colon cancer from the Cancer and Leukemia Group B 9581 and Quick and Simple and Reliable (QUASAR) trials. We conducted an independent, prospectively designed clinical validation study of Recurrence Score, with prespecified end points and analysis plan, in archival specimens from patients with stage II and III colon cancer randomly assigned to fluorouracil (FU) or FU plus oxaliplatin in National Surgical Adjuvant Breast and Bowel Project C-07.

METHODS

Recurrence Score was assessed in 892 fixed, paraffin-embedded tumor specimens (randomly selected 50% of patients with tissue). Data were analyzed by Cox regression adjusting for stage and treatment.

RESULTS

Continuous Recurrence Score predicted recurrence (hazard ratio for a 25-unit increase in score, 1.96; 95% CI, 1.50 to 2.55; P < .001), as well as disease-free and overall survival (both P < .001). Recurrence Score predicted recurrence risk (P = .001) after adjustment for stage, mismatch repair, nodes examined, grade, and treatment. Recurrence Score did not have significant interaction with stage (P = .90) or age (P = .76). Relative benefit of oxaliplatin was similar across the range of Recurrence Score (interaction P = .48); accordingly, absolute benefit of oxaliplatin increased with higher scores, most notably in patients with stage II and IIIA/B disease.

CONCLUSION

The 12-gene Recurrence Score predicts recurrence risk in stage II and stage III colon cancer and provides additional information beyond conventional clinical and pathologic factors. Incorporating Recurrence Score into the clinical context may better inform adjuvant therapy decisions in stage III as well as stage II colon cancer.

DNA repair gene ERCC1 and XPD polymorphisms predict glioma susceptibility and prognosis

AIMS

We conducted a case-control study in a Chinese population to clarify the association between polymorphisms in ERCC1 and XPD and susceptibility and survival of glioma.

METHODS

A total of 393 cases and 410 controls were selected from March 2007 to December 2011. Genotyping of ERCC1 and XPD was conducted by TaqMan assays using the ABI Prism 7911HT Sequence Detection System. All analyses were performed using the STATA statistical package.

RESULTS

Polymorphisms in ERCC1 118C/T, ERCC1 8092C/A and XPD Asp312Asn showed no statistically significant difference between glioma cases and controls. However, individuals with the XPD 751Gln/Gln genotype had an increased risk of developing glioma compared with those with the Lys/Lys genotype (adjusted OR=1.64, 95% CI: 1.06-2.89). The ERCC1 118T/T genotype was associated with significantly higher median survival than the ERCC1 C/C genotype (HR=0.67, 95%CI=0.35-0.96). In addition, individuals with XPD 751Gln/Gln had a lower median survival time than XPD Lys/Lys carriers (HR=0.54, 95%CI=0.37- 0.93).

CONCLUSION

In conclusion, we observed that the XPD 751Gln/Gln genotype is associated with glioma susceptibility, and ERCC1 118 T/T and XPD 751Gln/Gln genotypes confer a significantly better prognosis.