The potential predictive value of DEK expression for neoadjuvant chemoradiotherapy response in locally advanced rectal cancer

BACKGROUND

Limited data are available regarding the ability of biomarkers to predict complete pathological response to neoadjuvant chemoradiotherapy in locally advanced rectal cancer. Complete response translates to better patient survival. DEK is a transcription factor involved not only in development and progression of different types of cancer, but is also associated with treatment response. This study aims to analyze the role of DEK in complete pathological response following chemoradiotherapy for locally advanced rectal cancer.

METHODS

Pre-treated tumour samples from 74 locally advanced rectal-cancer patients who received chemoradiation therapy prior to total mesorectal excision were recruited for construction of a tissue microarray. DEK immunoreactivity from all samples was quantified by immunohistochemistry. Then, association between positive stained tumour cells and pathologic response to neoadjuvant treatment was measured to determine optimal predictive power.

RESULTS

DEK expression was limited to tumour cells located in the rectum. Interestingly, high percentage of tumour cells with DEK positiveness was statistically associated with complete pathological response to neoadjuvant treatment based on radiotherapy and fluoropyrimidine-based chemotherapy and a marked trend toward significance between DEK positiveness and absence of treatment toxicity. Further analysis revealed an association between DEK and the pro-apoptotic factor P38 in the pre-treated rectal cancer biopsies.

CONCLUSIONS

These data suggest DEK as a potential biomarker of complete pathological response to treatment in locally advanced rectal cancer.

Identification of Poor-outcome Biliopancreatic Carcinoma Patients With Two-marker Signature Based on ATF6α and p-p38 "STARD Compliant"

Biliopancreatic cancer is one of the most aggressive solid neoplasms, and incidence is rising worldwide. It is known that ATF6α is one of the transmembrane proteins that acts crucially in endoplasmic reticulum stress response, and knockdown induces apoptosis of pancreatic cells. Apart from this, p-p38 has been previously correlated with better outcome in pancreatic cancer. Interestingly, ATF6α knockdown pancreatic cells showed increased p-p38. The aim of this study was to evaluate the expression of these 2 proteins, p-p38 and ATF6α, and their correlation with the outcome of biliopancreatic adenocarcinoma patients. Samples from patients with biliopancreatic adenocarcinoma that underwent pancreaticoduodenectomy from 2007 to 2013 were used to construct a tissue microarray to evaluate p-p38 and ATF6α proteins by immunohistochemistry. We observed that both markers showed a tendency to impact in the time to recurrence; then a combination of these 2 proteins was analyzed. Combination of ATF6α(high) and p-p38(low) was strongly associated with a higher risk of recurrence (hazard ratio 2.918, P = 0.013). This 2-protein model remained significant after multivariate adjustment.We proposed a 2-protein signature based on ATF6α(high) and p-p38(low) as a potential biomarker of risk of recurrence in resected biliopancreatic adenocarcinoma patients.

Identification of predictive circulating biomarkers of bevacizumab-containing regimen efficacy in pre-treated metastatic colorectal cancer patients

BACKGROUND

To identify whether circulating levels of angiogenesis-related factors may be predictive of bevacizumab efficacy in pre-treated metastatic colorectal cancer (mCRC) patients.

METHODS

Pre-treatment serum levels of 24 cytokines were measured using a multiplex bead assay (MBA) in 32 pre-treated mCRC patients treated with irinotecan plus bevacizumab-based salvage therapy. Macrophage-derived chemokine (MDC), interleukins (ILs) 8 and 6 levels were also validated by enzyme-linked immunosorbent assay (ELISA) at different time points during therapy.

RESULTS

Higher epidermal growth factor (EGF) and MDC baseline levels (2.2- and 1.4-fold, respectively) and lower IL-10, IL-6 and IL-8 levels (0.2-, 0.6-, and 0.6-fold, respectively, P<0.05) were observed in patients responding to therapy. Baseline levels of these five serum factors compose a risk signature that may define the subset of patients most likely to benefit from bevacizumab-based therapy in terms of response rate and survival times. A positive correlation was found between MBA and ELISA results (P<0.01). Treatment exposure increased MDC and had opposite effects on IL-8 levels, which were decreased (P<0.05).

CONCLUSION

This study suggests that a set of inflammatory and angiogenesis-related serum markers may be associated with the efficacy of bevacizumab-containing regimen.

P2-09-02: Predicting Response to Bevacizumab in Primary Breast Cancer Using 18F-Fluorothymidina (FLT) and 18F-Misonidazole (MISO) Positron Emission/Computed Tomography (PET/CT) as Imaging Biomarkers

Background: To investigate the hypothesis that early changes in tumor proliferation and hypoxic status induced by bevacizumab and assessed by imaging biomarkers might predict response to bevacizumab therapy.

Methods: 73 chemotherapy naïve, stage II-III breast cancer (BC) patients (pts) were enrolled in the training set of this phase II, single-arm, multicenter and prospective clinical trial from October 2009 until November 2010. Pts received single infusion of bevacizumab (15 mg/kg) (C1) 3 weeks prior to the beginning of neoadjuvant chemotherapy (NAC) consisting in 4 cycles of docetaxel (60 mg/mq), doxorubicin (50 mg/mq) and bevacizumab (15 mg/kg) every 21 days (C2-C5) following by surgery. Tumor proliferation and hypoxic status were evaluated using FLT and MISO PET/CT at baseline and 14–21 days after bevacizumab (C1). Standardized uptake values (SUV) for FLT and MISO and ratios to reference tissues, mediastinum (T/Me) or muscle (T/Mu), for MISO were calculated. Pathological response on surgical specimens was assessed according to Miller/Payne grading system. Pts with reduction in tumor cells &gt;30% (G3-G4-G5) or &lt;30% (G1-G2) were respectively considered as responders and no-responders. Association between pathological response, baseline and changes induced by bevacizumab (C1) in imaging biomarkers was analyzed using Mann-Whitney test. Receiver operating characteristic (ROC) curve was performed to test sensitivity and specificity of the biomarker found associated to response. Its value as independent predictor was tested in multivariate analysis using logistic regression. Results: Median baseline MISO and FLT SUV values in tumors were 1.2 (range 0.69−2.39) and 2.89 (range 0.97−7.18). Significant change after C1 was observed in FLT (2.7 vs 1.8, p&lt;0.001) but no in MISO uptake. Fifty-two (74%) pts achieved response (G3-G4-G5) whether 18 (24%) were considered as no responder (G1-G2); for 3 (4%) patients Miller/Payne tumor evaluation was not available. Response showed a trend toward an association with negative estrogen receptors (ER) expression (p=0.08) and triple negative tumors (11/73) (p=0.05). FLT SUV baseline and changes after C1 in MISO SUV, T/Mu and T/Me were all significantly associated with pathological response (p=0.057, 0.03, 0.016, 0.010). ER expression and T/Mu change remained significantly associated with response in multivariate analysis (OR=24.8, IC95% 1.8-334, p=0.01 and OR=0.95, IC 95% 0.92−0.99, p value=0.02). Decrease in MISO T/Mu uptake &gt;20% yielded a ROC curve area of 0.7 (95% CI: 0.56 - 0.85) with 94% sensitivity and 87% specificity. Conclusion: Bevacizumab determined a marked decrease in tumor proliferation. Interestingly, a decrease greater than 20% in tumor hypoxic status after C1 and assessed by MISO was found significantly associated with pathological response suggesting a potential value of early decrease in hypoxic tumor status as predictive biomarker of response. Bevacizumab, causing normalization of the tumor microvasculature, seems to potentiate the effect of cytotoxic agents on primary BC. A validation set is warranted to confirm these findings.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-09-02.

P2-08-05: Use of Dynamic Contrast-Enhanced MR Imaging To Predict Pathological Response in Primary Breast Cancer

Purpose: To investigate the effect of bevacizumab infusion on vascular parameters assessed by dynamic contrast-enhanced magnetic resonance (DCE-MR) imaging and to test their association with pathological response in primary breast cancer.

Materials and Methods: 73 patients (median age, 47 ys; age range, 29–70 ys) with biopsy-proven, previously untreated, primary breast cancer were recruited from October 2009 to November 2010 in this phase II, multicenter and non-randomized clinical trial. Patients (pts) received single infusion of bevacizumab (15 mg/kg) (C1) 3 weeks prior to the beginning of neoadjuvant chemotherapy consisting in 4 cycles of docetaxel (60 mg/mq), doxorubicin (50 mg/mq) and bevacizumab (15 mg/kg) every 21 days (C2-C5) following by surgery. All pts underwent DCE-MR imaging before and 14–21 days after C1. Quantitative and semiquantitative kinetic parameters were calculated at baseline and after C1, including the volume transfer constant (K(trans)), which primarily reflects the wash-in of the contrast agent, the backflow rate contrant (K(ep)), extracellular volume fraction (V(e)) and the initial area under the gadolinium concentration-time curve over 60 seconds (IAUGC(60)). Changes in the DCE-MRI kinetic parameters K(trans), K(ep), V(e) and IAUGC(60) were calculated and Wilcoxon test was used to assess significant effects induced by bevacizumab on kinetic parameters. Pathological response on surgical specimens after C5 was assessed according to Miller and Payne classification. Pts with tumor reduction &gt;30% were considered as responders (G3-G4-G5) whether tumor reduction &lt;30% were considered as no responders (G1-G2). DCE-MR imaging parameters and clinical-pathological characteristics were correlated with pathological response using Mann-Whitney test in univariate and logistic regression in multivariate analyses. Receiver operating curves (ROC) was used to define the best cut-off of the parameter found associated with pathological response.

Results: DCE-MRI was performed before (n=72) and after (n=71) C1. K(trans), K(ep), V(e) and IAUCG(60) values were significantly different at the baseline and after C1 (p&lt;0.01). Median changes were, respectively, −51, −101, −52.5 and −4.8. Fifty-two (74%) pts achieved response (G3-G4-G5) after C5 whether 18 (24%) were considered as no responder (G1-G2); for 3 (4%) patients Miller/Payne tumor evaluation was not available. At univariate analysis, negative estrogen receptor (ER) status and higher post-C1 K(ep) (p=.057) showed a trend toward an association with response. At multivariate analysis, only ER status remains a significant predictor of response (p= .04). Area under ROC curve for K(ep) was 0.65 (IC95% 0.05−0.8, p=.057)

Conclusion: Bevacizumab affects tumor vasculature, perfusion and permeability as showed by the significantly reduction in all kinetic vasculature parameters obtained in DCE-MR imaging after C1. However, in our population these changes were not associated with pathological response. On the other hand, backflow rate constant, K(ep), a perfusion-related parameter derived from DCE-MRI yielded after C1 major than 80, may be associated with higher pathological response with a specificity of 88% and sensitivity of 90%. Future studies are warranted to confirm these findings.

Citation Information: Cancer Res 2011;71(24 Suppl):Abstract nr P2-08-05.

RT-PCR versus immunohistochemistry for correlation and quantification of ERCC1, BRCA1, TUBB3 and RRM1 in NSCLC

BACKGROUND

Customized chemotherapy is increasingly used in the management of patients with advanced non-small cell lung cancer (NSCLC). However, the most reliable methodology to determine biomarker status is neither fully elucidated nor agreed upon. Accordingly, we evaluated the predictive efficiency of qRT-PCR and immunohistochemical analysis (IHC) on excision cross complementation group 1 (ERCC1), breast cancer susceptibility gene 1 (BRCA1), ribonucleotide reductase subunit M1 (RRM1) and class III β-tubulin (TUBB3).

PATIENTS AND METHODS

IHC and qRT-PCR on ERCC1, BRCA1, RRM1 and TUBB3 were performed on surgically resected tissue samples from NSCLC-patients included in a randomized trial. The median values of the biomarker expression dichotomized the population and were correlated to clinical endpoints.

RESULTS

Representative tissue samples from 33 patients showed no significant correlations between mRNA and protein expression. Predictive impact was demonstrated for all four biomarkers, when assessed by IHC, and reached significance for overall survival in patients with ERCC1-negative (14.3 vs. 8.5 months, p=0.018) and TUBB3-negative (18.5 vs. 11.10, p=0.027) tumours, while this was not the case for qRT-PCR.

CONCLUSIONS

IHC discriminated more effectively than qRT-PCR across four NSCLC-relevant biomarkers. The findings are further supported by the demonstrated lack of correlation between transcript and protein.

Association of RRM1 -37A>C polymorphism with clinical outcome in colorectal cancer patients treated with gemcitabine-based chemotherapy

BACKGROUND

To investigate whether single nucleotide polymorphisms (SNPs) in gemcitabine (GMB) metabolism genes were associated with clinical outcome in pre-treated metastatic colorectal cancer (mCRC) patients.

PATIENTS AND METHODS

SNPs of hCNT1, hENT1, CDA, dCTD and RRM1 genes were evaluated in 95 mCRC patients and detected using TaqMan genotyping assays. Association of genotypes with overall response rate (ORR), time to progression (TTP) and overall survival (OS) was tested by univariate and multivariate analysis. RRM1 -37A>C polymorphism was correlated with GMB IC50 value and with the RRM1 gene expression level in CRC cell lines.

RESULTS

The ORR was 38.9%. The median TTP and OS were 4 and 14.3 months, respectively. By multivariate analysis, patients carrying the RRM1 -37CC genotype or the CDA A-76 C-containing allele had a significantly higher likelihood of achieving a tumour response. RRM1 -37A>C polymorphism remained associated with clinical efficacy (TTP). In vitro experiments, in CRC cell lines, showed that the RRM1 A-37C genotype was associated with the levels of RRM1 expression and with GMB IC50 values. Finally, the down-regulation of RRM1 with a specific siRNA strongly influenced GMB sensitivity.

CONCLUSION

RRM1 -37A>C polymorphism may represent a useful biomarker to select mCRC patients most likely to benefit from GMB-based salvage therapy.

Dose-finding study and pharmacogenomic analysis of fixed-rate infusion of gemcitabine, irinotecan and bevacizumab in pretreated metastatic colorectal cancer patients

BACKGROUND

To determine the dose-limiting toxicity (DLT), maximum tolerated dose, recommended dose (RD) and preliminary evidence of activity of escalating doses of irinotecan (CPT-11) fixed-dose-rate infusional gemcitabine (FDR-GMB) and bevacizumab in pretreated metastatic colorectal cancer (mCRC) patients. Pharmacogenomic analysis was performed to investigate the association between VEGF single-nucleotide polymorphisms and clinical outcome.

PATIENTS AND METHODS

A total of 89 mCRC patients were recruited in a two-step study design; 28 were included in the dose-finding study and 59 in the pharmacogenomic analysis. The FDR-GMB of 1000 mg m⁻², bevacizumab 5 mg kg⁻¹ and CPT-11 doses ranging from 100 to 160 mg m⁻² were explored. The VEGF protein serum levels were quantified by EIA. Allelic discrimination was performed to genotype polymorphisms in the VEGF gene.

RESULTS

CPT-11 RD was 150 mg m⁻². Diarrhoea and neutropenia were the DLT. After a median follow-up of 42 months, the median time to progression (TTP) and overall survival were 5.2 and 19.9 months, respectively. VEGF levels were significantly correlated with VEGF-2578AA and VEGF-460CC genotypes, and a trend was observed with VEGF+405GG genotype. The presence of any of these genotypes correlated with a longer median TTP (8.8 vs 4.5 months, P=0.04).

CONCLUSION

The triplet combination tested in this study is effective and well tolerated. A possible predictive role for VEGF gene polymorphisms and baseline VEGF circulating levels is suggested.

Role of primary miRNA polymorphic variants in metastatic colon cancer patients treated with 5-fluorouracil and irinotecan

MicroRNAs are non-coding RNAs that can block mRNA translation and influence mRNA stability. Recent evidence indicates that miRNA variations can affect drug resistance, efficacy, and metabolism, opening new avenues of pharmacogenomics research. We investigated associations between polymorphisms in both miRNA-containing genomic regions (primary and precursor miRNA) and in genes related to miRNA biogenesis with clinical outcome in metastatic colorectal cancer (mCRC) patients treated with 5-fluorouracil and irinotecan (CPT-11). Eighteen single-nucleotide polymorphisms (SNPs) were analyzed in 61 patients. A significant association with tumor response and time to progression (TTP) was found for SNP rs7372209 in pri-miR26a-1 (P=0.041 and P=0.017, respectively). The genotypes CC and CT were favorable when compared with the TT variant genotype. In addition, SNP rs1834306, located in the pri-miR-100 gene, significantly correlated with a longer TTP (P=0.04). In the miRNA-biogenesis pathway, a trend was identified between SNP rs11077 in the exportin-5 gene and disease control rate (P=0.076). This study is the first to suggest a relationship between treatment outcome and SNPs in the miRNA-biogenesis machinery, in both primary and precursor miRNAs. Our results suggest that miRNA polymorphic variants might be useful predictors of clinical outcome in mCRC patients treated with 5-fluorouracil and CPT-11 combination.

Predictive value of Ile105Val polymorphism of the gluthatione-S-transferase P1 in patients with metastatic colorectal cancer (m CRC) treated with the triplet combination of irinotecan, oxaliplatin, and capecitabine

2544

Background: Several phase I/II trials have shown that the triplet combination of oxaliplatin, irinotecan and capecitabine is a feasible and active in solid tumors. We aimed to investigate whether germline polymorphisms may be predictors of clinical outcome in mCRC pts treated with this combination. Methods: The following genetic polymorphisms were analysed: glutathione S-transferase (GSTP1-Ile105Val, GSTT1 and GSTM1 deletion), TYMS (TS-5´UTR 2R/3R; TS-5´G/C; TS-3´UTR 6-bp deletion), MTHFR 1298A>C, UGT1A1, ERCC1, XPD. Polymorphisms from peripheral lymphocytes were detected using the TaqMan genotyping assays (Applied Biosystems, CA). Univariate analysis (Fisher´s exact test for response; log-rank test for TTP and OS) was performed to examine associations between polymorphisms and clinical outcome. Results: Blood samples for 63 out of 72 prospectively enrolled pts were tested for genomic analysis. Median age was 57 (32–78), median ECOG 1(0–2), median number of cycles administered 6 (1–13), median number of metastatic sites was 1 (1–4). M/F: 50/22. Risk according to Köhne classification was low (52.8% of pts), intermediate (26.4%) and high (8.3%). Overall response rate (ORR) was 62.5%. Median progression-free survival (PFS) was 9.87 months (95% CI; 7.6–12) and median overall survival was 24.6 months (95% CI; 19.5–29.7). A significant association was observed between MTHFR 1298A>C and haematological toxicity, with C/C genotype pts being at higher risk of grade 3–4 neutropenia (50% vs. 28%, p = 0.035) and leucopenia (50% vs. 15%, p = 0.04). Heterozygous and homozygous GSTP-105Val showed a significant superior response rate (80%) compared to only 40% in pts harbouring the GSTP1–105Ile/Ile genotype (p = 0.008, Fisher´s exact test). PFS was also adversely affected in pts with GSTP1–105Ile/Ile (5.2 months vs. 12.3 months in those pts with at least one GSTP1–105Val allele, p = 0.001). In the multivariate analysis, the relative risk for progression was 3.4 (95% CI; 1.3–9.1) for the GSTP1–105Ile/Ile genotype (p = 0.01). Conclusions: The GSTP1-Ile105Val polymorphism is a strong predictor of clinical outcome for XELOXIRI therapy in mCRC pts.

No significant financial relationships to disclose.

Pharmacogenomic analysis of the triplet combination of gemcitabine, oxaliplatin, and cetuximab as salvage therapy for metastatic colorectal cancer (mCRC) patients

e14531

Background: We have previously reported that biweekly gemcitabine-based therapy was active in pretreated mCRC pts (De la Cruz et al, ASCO GI 2008, abstr 377). We aimed to investigate whether germ line polymorphisms may be predictors of clinical outcome in mCRC pts treated with this combination. Methods: We evaluated SNPs of genes involved in gemcitabine metabolism (CDA, dCDK, RRM1, DCTD, SLC28A1), DNA repair (XRCC1, XRCC 3, ERCC1, XPD) and two IgG Fcγ R polymorphisms (Fcγ RIIa- H131R and Fcγ RIIIa-V158F), reported to be predictive of cetuximab-based therapy, even in K-ras mutated pts. Whole blood was collected and DNA extracted from peripheral lymphocytes using a DNA isolation Kit (Qiagen, CA). Polymorphisms were detected using the TaqMan genotyping assays (Applied Biosystems, CA). Clinical response was evaluated according to RECIST criteria. Univariate analysis (Fisher´s exact test for response; log-rank test for TTP and OS) was performed to examine associations between polymorphisms and clinical outcome. Results: Blood samples of 35 out of 39 enrolled pts were tested for genomic analysis. Patient‘s characteristics are as follows; M/F: 26/13, median age: 59 years, median number of prior chemotherapy lines: 2 (1–4), Köhne risk groups; low: 8 pts, intermediate: 18 pts, high: 13 pts. After a median follow-up of 20 months, median progression-free survival (PFS) is 6.7 months (95% CI; 5.2–8.3) and median overall survival 15.4 m (95% CI; 14.7–16.1). Overall response rate (ORR) was 53.8%. RRM1 R284R SNPs (p=0.06), T741T (p=0.02) and RRM1–524CT (p=0.04) were linked to clinical responsiveness. All pts possessing 2 or 3 favourable RRM1 SNPs responded. ORR was 53.3% for pts with no favourable SNPs versus 85% for pts with any favourable SNP (p=0.04). ORR was also significantly higher in pts with any histidine allele in the Fcγ RIIa polymorphism (93% vs. 60%, p=0.034). Median PFS was adversely affected in pts harbouring no favourable RRM1 SNPs (4.2m versus 6.7 months, p=0.019) and in those pts with homozygous Fcγ RIIa-131R allele (4.4 vs. 7.5 months, p=0.007). Conclusions: Polymorphic variants of RRM1 and Fcγ RIIa may play a key role in the efficacy of gemcitabine and cetuximab-based therapy for mCRC pts.

No significant financial relationships to disclose.

Cluster mir-17–92 is differentially expressed in colon cancer patients and embryonic colon tissue and may contribute to carcinogenesis through E2F1 expression

10525

Background: Mature microRNAs (miRNA) are small RNA molecules that act as negative regulators of gene expression, either inhibiting mRNA by blocking its translation into protein or destroying it by RNA interference. Many miRNAs participate in essential processes, including normal embryonic development and carcinogenesis. Methods: We have assessed 156 mature miRNAs in colon tissue from eleven 7–12-week human embryos and 44 colorectal human samples. Data were analyzed using TIGR Multiexperiment viewer. Two multivariate permutation test were performed. Potential target genes of differentially expressed miRNAs are evaluated by western blot. Results: 28 miRNAs were expressed in stage I tumor tissue but not in the corresponding normal tissue, and 13 of these 28 miRNAs (46%) were also expressed in embryonic tissue. Sixty-four miRNAs were differentially expressed in stage II tumor tissue, and 29 of these 64 miRNAs (45%) were also expressed in embryonic tissue. Some miRNAs that are active during embryogenesis, such as mir-17–92, miR-181a, miR-181b and miR-181c (linked to HOXA11), and miR-10a (linked to HOXB8)23, are also expressed during tumor growth. The analysis of 156 miRNAs by K-means support revealed two well-differentiated groups: the embryos of 7–8 weeks and those of 9–12 weeks. Lower miRNA expression was also observed in tumor tissue from stage I in comparison with stage II disease (P=0.014). Analysis of potential target genes revealed that cluster mir-17–92 is differentially expressed in colon cancer and embryonic tissue and may contribute to carcinogenesis through E2F1 expression. Conclusions: Our findings indicate that miRNAs expressed during the embryonic development of the human colon are also expressed in colon tumor tissue. During colon organogenesis, miRNA expression is at first high, while cells are still undifferentiated, but expression levels decrease as cells become more differentiated. In contrast, during the development of colorectal cancer, this process is reversed.

No significant financial relationships to disclose.

A randomised, placebo-controlled, double-blind phase II study of raltitrexed and gefitinib vs raltitrexed alone as 2nd line chemotherapy in subjects with advanced colorectal cancer (CRC). GON group study (Grupo Oncologico del Norte)

14523

Background: Second-line monotherapy activity in patients with metastatic CRC is low with an objective response rate of 9% in phase II-III studies (Viéitez et al, Am J Clin Oncol 2003; Rougier y cols., 1998). Gefitinib has shown activity in vitro and in animal models against colon cancer cell lines, and has shown to increase the activity of raltitrexed (Cardiello et al, Clin Cancer Res 2000). Methods: A multi-center randomized, double blind, phase II study was initiated in patients with metastatic CRC who failed prior therapy based on 5-FU LV plus OXL or/and CPT and measurable disease. Patients were randomized to received Raltitrexed, 3 mg/m2 IV q3w, (arm A) or Raltitrexed plus Gefitinib, 250 mg PO OD (arm B). Primary end-point was time to progression (TTP); Secondary end-point was objective tumour response rate (ORR) based on the RECIST criteria at six month, overall survival (OS) and safety. Results: Between Dec 2003 and Oct. 2005, 76 patients were recruited in 7 centers. Median age was 65.0 (range 75–31) and 63.5 (range 76–40) years for arm A and B respectively; demographics characteristics were well balanced between both arms including sex, race or other previous mayor conditions. Both treatment arms were well tolerated. Grade 3/4 toxicity in Arm A was: anorexia 10.5% (4), asthenia 10.5% (4), liver toxicity 10.5% (4), nausea 5.3% (2), diarrhea 5.3% (2), abdominal pain 2.6% (1), neutropenia 2.6% (1), thrombopenia 2.6% (1), renal failure 2.6% (1). Grade 3/4 toxicity in Arm B included: anemia 2.6% (1), liver toxicity 7.9% (3), diarrhea 5.3% (2), skin rash 2.6% (1), melenas/upper digestive bleeding 2.6% (1), fever 2.6% (1). ORR was 5.3% (2/38) (95%CI: 0.64–17.75) and 7.9% (3/38) (95%CI: 1.66–21.38) for arm A and B. Median TTP was 72 (95%CI: 59–132) and 63 (95%CI: 57–84) days; median OS was 291 (95%CI: 255–539) and 361 (95%CI: 283–533) days; and median duration of treatment was 74.5 (range 21–274) and 63.5 (range 12–324) days for arm A and B. Conclusions: Addition of Gefitinib to Raltitrexed in pretreated patients with advanced CRC is well tolerated, with manageable toxicity profile, but not increases Raltitrexed efficacy.

No significant financial relationships to disclose.

Gene expression profile related to oxaliplatin resistance in a panel of sensitive human colorectal cancer cell lines with acquired resistance to the drug

13143

Background: Platinum drugs resistance acquisition is a complex process based in the alteration of genes that belong to several pathways related to drug metabolism. To clarify the multifactoriality of these mechanisms, we analyzed gene expression profile in the four CCR cell lines HT29, LoVo, DLD1 and LS513, and their sublines HTOXAR, LOVOXAR, DLDOXAR y LSOXAR that we induced oxaliplatin resistance in our laboratory. The aim of this work consisted on comparing gene expression profile between resistant cells group (cluster R) and sensitive cells group (cluster S) to determine genes and pathways that could play a role in oxaliplatin resistance acquisition process. Methods: Resistance level determination by MTT assay. Gene expression profile analysis through microarray technology (Human 19K oligo): labeled with Genisphere 3DNA Array350 (Dye Swap), and data analysis using Imagene 4.1, ArrayNorm1.7.2 y Genesis 1.5.0 (ANOVA). Results: According to ANOVA analysis of cluster R versus cluster S, we obtained 32 genes that showed significant changes in expression. 15 of these genes were up regulated and 17 were down regulated. We emphasize genes that belong to pathways previously related to oxaliplatin metabolism (AKT1, TRIP and NLK), family of genes that does not expressed in the same chromosome (KIAA0232 and KIAA0256, SLC39A9 and SLC30A9), and family of genes that had previously related to carcinogenesis processes (KRT19, KRT18 and KRT8). Conclusions: It is possible to develop oxaliplatin resistant CCR cell lines. In our oxaliplatin acquired resistance model, 32 genes showed gene expression changes between groups. These genes belong to signal transduction pathways and cellular integrity mechanisms and they could be a future oxaliplatin resistance prediction profile in colorectal cancer patients.

No significant financial relationships to disclose.