FOLFOX Response Research Articles

ERCC1 and MGMT Methylation as a Predictive Marker of Relapse and FOLFOX Response in Colorectal Cancer Patients from South Tunisia.

Genetic and epigenetic modifications present a major cause of relapse and treatment failure in colorectal cancer. This study aims to appreciate the prognostic and predictive value of ERRC1 and MGMT methylation. We also studied the prognostic impact of the ERCC1 rs11615 polymorphism as well as its expression. Methylation profiles of ERCC1 and MGMT were tested by methylation-specific PCR. A polymorphism of ERCC1 was studied using PCR-RFLP and its expression was examined by immunohistochemistry. ERCC1 was methylated in 44.6% of colorectal adenocarcinoma while MGMT was methylated in 69% of cases. MGMT methylation was strongly associated with lymph node metastasis, lymph invasion, venous invasion, perineural invasion, distant metastasis and relapse. Patients with methylation of both genes were more likely to have a poor prognosis and display chemoresistance. IHC analysis revealed that ERCC1 staining was noted in 52.8% of colorectal adenocarcinoma and inversely related to distant metastasis and cancer recurrence. Kaplan Meier analysis revealed that the worst overall survival was significantly associated with ERCC1 and MGMT methylation while decreased ERCC1 expression and T/T genotype exhibited the best overall survival. The methylation of MGMT, alone or combined with ERCC1, is predictive for poor prognosis, short overall survival and chemotherapy response in colorectal cancer.

Combined expression of HIF1α, VEGF and HER2 predicts metastasis, relapse and response to combination chemotherapy in colorectal cancer patients

Addressing a single target is the frequent development of drug resistance followed by cancer relapse and treatment failure. Therefore, assessment of simultaneous expression of target molecules is essential to choose the optimal combination therapy for each colorectal cancer patient.This study aims to evaluate the immunohistochemical expression of HIF1α, HER2 and VEGF and to clarify their clinical significance as prognostic factors and predictive markers of FOLFOX (combination chemotherapy inclusive of Leucovorin calcium, Fluorouracil and Oxaliplatin response).Marker expression was retrospectively evaluated by immunohistochemistry in 111 patients with colorectal adenocarcinomas from south Tunisia, followed by statistical analysis.The immunohistochemical staining revealed that 45 %, 80.2 %, 86.5 % and 25.5 % of specimen were positive for nuclear, cytoplasmic HIF1α expression, VEGF and HER2 respectively. Nuclear HIF1α and VEGF were associated with worst prognosis while cytoplasmic HIF1α and HER2 were correlated with favourable prognosis. Multivariate analysis confirms the association between nuclear HIF1α, distant metastasis, relapse, FOLFOX response and 5 years overall survival. HIF1α positivity and HER2 negativity were significantly associated to short survival. Combined immunoprofiles HIF1α+/VEGF+, HIF1α+/HER2-, HIF1α+/VEGF+/HER2- were associated to distant metastasis, cancer relapse and short survival. Interestingly, our findings confirmed that patients bearing a HIF1α positive tumor were significantly more resistant to FOLFOX compared to negative ones (p = 0.002, p ≤ 0.001). Positive expression of HIF1α and VEGF, or decreased expression of HER2 was each associated with poor prognosis and short overall survival. In summary, we found that expression of nuclear HIF1α, alone or combined with VEGF and HER2 serves as a predictive marker of poor prognosis and FOLFOX response in colorectal cancer from south Tunisia.

Identification of Two Subgroups of FOLFOX Resistance Patterns and Prediction of FOLFOX Response in Colorectal Cancer Patients

To dissect gene expression subgroups of FOLFOX resistance colorectal cancer(CRC) and predict FOLFOX response, gene expression data of 83 stage IV CRC tumor samples (FOLFOX responder n = 42, non-responder n = 41) are used to develop a novel iterative supervised learning method IML. IML identified two mutually exclusive subgroups of CRC patients that rely on different DNA damage repair proteins and resist FOLFOX. IML was validated in two validation sets (HR = 2.6, p Value = 0.02; HR = 2.36, p value = 0.02). A subgroup of mesenchymal subtype patients benefit from FOLFOX. Different subgroups of FOLFOX nonresponders may need to be treated differently.

Oxaliplatin-DNA Adducts as Predictive Biomarkers of FOLFOX Response in Colorectal Cancer: A Potential Treatment Optimization Strategy.

FOLFOX is one of the most effective treatments for advanced colorectal cancer. However, cumulative oxaliplatin neurotoxicity often results in halting the therapy. Oxaliplatin functions predominantly via the formation of toxic covalent drug-DNA adducts. We hypothesize that oxaliplatin-DNA adduct levels formed in vivo in peripheral blood mononuclear cells (PBMC) are proportional to tumor shrinkage caused by FOLFOX therapy. We further hypothesize that adducts induced by subtherapeutic "diagnostic microdoses" are proportional to those induced by therapeutic doses and are also predictive of response to FOLFOX therapy. These hypotheses were tested in colorectal cancer cell lines and a pilot clinical study. Four colorectal cancer cell lines were cultured with therapeutically relevant (100 μmol/L) or diagnostic microdose (1 μmol/L) concentrations of [14C]oxaliplatin. The C-14 label enabled quantification of oxaliplatin-DNA adduct level with accelerator mass spectrometry (AMS). Oxaliplatin-DNA adduct formation was correlated with oxaliplatin cytotoxicity for each cell line as measured by the MTT viability assay. Six colorectal cancer patients received by intravenous route a diagnostic microdose containing [14C]oxaliplatin prior to treatment, as well as a second [14C]oxaliplatin dose during FOLFOX chemotherapy, termed a "therapeutic dose." Oxaliplatin-DNA adduct levels from PBMC correlated significantly to mean tumor volume change of evaluable target lesions (5 of the 6 patients had measurable disease). Oxaliplatin-DNA adduct levels were linearly proportional between microdose and therapeutically relevant concentrations in cell culture experiments and patient samples, as was plasma pharmacokinetics, indicating potential utility of diagnostic microdosing.

Use of gene set analysis (GSA) for molecular classification of responders and nonresponders to FOLFOX therapy in colorectal cancer (CRC).

3628 Background: Folinic acid (FOL) fluorouracil (F) and oxaliplatin (OX) chemotherapy is a commonly used therapy for CRC. Lacking in current literature are clinically relevant classifiers for potential responders. GSA technique is statistical method that detects significance of sets of genes, instead of examining a gene-by-gene basis. The objective of this study was to identify differential functionally annotated gene expression profiles associated with response to FOLFOX therapy in CRC tumors using gene-by-gene and GSA approaches. Methods: Genome wide expression profile data were collected on pre-treatment tumor tissues from patients with unresectable CRC receiving FOLFOX therapy (n = 83, Affymetrix HG U133A, GSE28702, Tsuji et al. BJC 2012). Gene expression was compared between responders (n = 42) and Non-responders (n = 41). GSA was conducted on 3272 curated gene sets from the Molecular Signatures Database (Subramanian, Tamayo et al. 2005, PNAS 102, 15545-15550) annotated by biological pathway, biochemical function and clinical behavior. Significant analysis of Microarray (SAM) and GSA (Tibshirani et al.) was done to identify gene sets associated with FOLFOX response. Results: Differential expressions of 23 genes were significantly associated with response, based on a single gene approach (p-value < 0.05). 13 of these were located on Chromosome 17 (p < 0.001). Among these, the top 5 ranked genes included NPEPPS, MBTD1, CEP44, LTA4H and CPNE4 which are involved in metal ion binding and aminopeptidase activity. GSA revealed only 44 out of 3272 gene sets were significantly associated with response, with a false discovery rate less than 25%. Increased expression of B-lymphocyte differentiation and Ras-signalling-related gene sets was associated with responders while mTOR signaling and hematopoietic stem cell-related genes set were associated with non-responders. Conclusions: Our data showed that differential biological pathways could be identified to predict response to FOLFOX therapy for CRC patients. Analysis may be useful to help define clinically relevant biologic subtypes among patients with metastatic colorectal cancer.

Gene expression signature and response to the use of leucovorin, fluorouracil and oxaliplatin in colorectal cancer patients

FOLFOX (a combination of leucovorin, fluorouracil and oxaliplatin) has achieved substantial success in the treatment of colorectal cancer (CRC) patients. However, about half of all patients show resistance to this regimen and some develop adverse symptoms such as neurotoxicity. In order to select patients who would benefit most from this therapy, we aimed to build a predictor for the response to FOLFOX using microarray gene expression profiles of primary CRC samples. Forty patients who underwent surgery for primary lesions were examined. All patients had metastatic or recurrent CRC and received modified FOLFOX6. Responders and nonresponders were determined according to the best observed response at the end of the first-line treatment. Gene-expression profiles of primary CRC were determined using Human Genome GeneChip arrays U133. We identified discriminating genes whose expression differed significantly between responders and nonresponders and then carried out supervised class prediction using the k-nearest-neighbour method. We identified 27 probes that were differentially expressed between responders and nonresponders at significant levels. Based on the expression of these genes, we constructed a FOLFOX response predictor with an overall accuracy of 92.5%. The sensitivity, specificity, positive and negative predictive values were 78.6%, 100%, 100% and 89.7%, respectively. The present model suggests the possibility of selecting patients who would benefit from FOLFOX therapy both in the metastatic and the adjuvant setting. To our knowledge, this is the first study to establish a prediction model for the response to FOLFOX chemotherapy based on gene expression by microarray analysis.

Methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms and FOLFOX response in colorectal cancer patients

* Numerous clinical studies, including a few prospective ones, have reported conflicting results on the impact of gene polymorphisms related to fluorouracil (FU) and oxaliplatin pharmacodynamics. * This prospective study is the first to report that clinical response to FOLFOX is significantly related to methylenetetrahydrofolate reductase (MTHFR) gene polymorphisms (677C-->T and 1298A-->C), with a response rate of 37, 53, 63 and 80% in patients harbouring no, one, two or three favourable MTHFR alleles, respectively. * Only polymorphisms of genes related to oxaliplatin pharmacodynamics (GSTpi 105Ile-->Val and XPD 751Ly-->Gln) influenced progression-free survival. * These results corroborate the observation that response was related to the cumulative FU dose, whereas progression-free survival was related to the cumulative oxaliplatin dose. To test prospectively the predictive value of germinal gene polymorphisms related to fluorouracil (FU) and oxaliplatin (Oxa) pharmacodynamics on toxicity and responsiveness of colorectal cancer (CRC) patients receiving FOLFOX therapy. Advanced CRC patients (n= 117) receiving FOLFOX 7 therapy were enrolled. Gene polymorphisms relevant for FU [thymidylate synthase (TYMS, 28 bp repeats including the G-->C mutation + 6 bp deletion in 3'UTR), methylenetetrahydrofolate reductase (MTHFR, 677C-->T, 1298A-->C), dihydropyrimidine deshydrogenase (IVS14+1G-->A) and Oxa: glutathione S-transferase (GST) pi (105Ile-->Val, 114Ala-->Val), excision repair cross-complementing group 1 (ERCC1) (118AAT-->AAC), ERCC2 (XPD, 751Lys-->Gln) and XRCC1 (399Arg-->Gln)] were determined (blood mononuclear cells). None of the genotypes was predictive of toxicity. Response rate (54.7% complete response + partial response) was related to FU pharmacogenetics, with both 677C-->T (P= 0.042) and 1298A-->C (P= 0.004) MTHFR genotypes linked to clinical response. Importantly, the score of favourable MTHFR alleles (677T and 1298C) was positively linked to response, with response rates of 37.1, 53.3, 62.5 and 80.0% in patients bearing no, one, two or three favourable alleles, respectively (P= 0.040). Polymorphisms of genes related to Oxa pharmacodynamics showed an influence on progression-free survival, with a better outcome in patients bearing GSTpi 105 Val/Val genotype or XPD 751Lys-containing genotype (P= 0.054). These results show that response to FOLFOX therapy in CRC patients may be driven by MTHFR germinal polymorphisms.

Definition of oxaliplatin sensitivity in patients with advanced colorectal cancer previously treated with oxaliplatin-based therapy

4024 Background: Oxaliplatin combined with fluoropyrimidines is standard adjuvant therapy in stage III colon cancer and first-line therapy in stage IV colorectal cancer. Oxaliplatin can be reintroduced either at relapse, or after maintenance or after chemotherapy holidays. In this study we defined the sensitivity to oxaliplatin reintroduction based on the oxaliplatin-free interval. Methods: Stage IV pts entered in the OPTIMOX1 and 2 studies (FOLFOX4, FOLFOX7 followed by maintenance without oxaliplatin or chemotherapy holidays) and pts having relapsed after metastases surgery and neoadjuvant or adjuvant FOLFOX for resectable stage IV were eligible if they were rechallenged with FOLFOX. Endpoints were: survival from reintroduction according to interval between the last cycle of oxaliplatin first-line and reintroduction, survival and response at reintroduction according to first FOLFOX response and PFS. Results: 330 pts were included: male 60%, colon/rectum/both 62%/35%/2%, resectable/unresectable: 14%/86%, PS 0–1 / >1: 90%/10%, sites 1/>1: 57%/43%. 23 pts had adjuvant and 22 pts had neoadjuvant chemotherapy. 58 pts (18%) had FOLFOX reintroduction before progression. PFS/OS from reintroduction according to induction FOLFOX response were 8.7/19.5 mths if CR, 4.6/15.2 mths if PR, and 3.2/9.7 mths if SD (P=.0019/.01). PFS/OS from reintroduction according to induction FOLFOX PFS were 2.9/9.3 mths if PFS<6 mths, 4.6/14.7 mths if PFS 6–12 mths and 8.5/23.7 if PFS=12 mths. Table shows results according to intervals. There was no difference between 0–3 and 3–6 mths or 6–9 and 9–12 mths intervals. Conclusions: A prolonged interval between two FOLFOX therapies or a prolonged PFS at first-line FOLFOX predict the efficacy of oxaliplatin reintroduction. The interval between two FOLFOX therapies does not identify a completely refractory population. Resistance (PD rate) is divided by two at each 6 month intervals. [Table: see text] No significant financial relationships to disclose.