Background: The purpose of this study was to determine the efficacy and toxicity of oxaliplatin in combination with weekly bolus 5-fluorouracil (5-FU) and leucovorin (LV) in patients with 5-FU-pretreated advanced colorectal cancer. Methods: A total of 39 patients with documented 5-FU-resistant advanced colorectal cancer were enrolled. All 39 patients had previously received weekly high-dose 5-FU/LV (2,600 mg/m² 5-FU plus 100 mg/m² LV as 24-hour infusion) as first-line chemotherapy for metastatic disease. Oxaliplatin (85 mg/m²) was delivered as an intravenous infusion over 2 h on days 1 and 15, while 5-FU (500 mg/m²) and LV (20 mg/m²) were administered as an intravenous bolus on days 1, 8 and 15. One treatment course consisted of 3 consecutive weeks of therapy followed by a 1-week rest. Results: In an intent-to-treat analysis, the objective response rate for the 39 patients was 20.5% (95% confidence interval, 7.2–33.8%). The disease was stable in 19 patients (48.7%), and progressive in 11 (28.2%). The median survival for all 39 patients was 8.9 months. The median time to progression was 5.0 months. Grade 3/4 neutropenia occurred in only 1 patient (2.6%), and grade 2 and 3/4 peripheral neuropathy occurred in 10 (25.6%) and 5 (12.8%) patients, respectively. Conclusion: Oxaliplatin in combination with weekly bolus 5-FU/LV is also active in patients with advanced colorectal cancer where first-line treatment has failed.

Colorectal cancer (CRC) is a genetically heterogeneous disease with distinct morphological patterns. It has been shown that polypoid and ulcerative CRC displays different genetic alterations. In the present study, we aimed to investigate genes with differential expression patterns between ulcerative and polypoid CRC. cDNA microarray analysis was performed to compare the gene expression profiles in samples of ulcerative and polypoid CRC with paired normal mucosa samples. Potential candidate genes were further validated using reverse transcription-quantitative polymerase chain reaction (RT-qPCR), western blot analysis and immunohistochemistry. The epigenetic regulation of gene expression was investigated using methylation-specific PCR (MSP). cDNA microarray analysis identified 11 upregulated and 14 downregulated genes which were differentially expressed in samples from both tumor types compared to the matched normal mucosa samples. Among these, S100P was the only upregulated gene preferentially associated with polypoid CRC (P=0.032). The samples of polypoid CRC displayed significantly higher S100P protein and mRNA expression levels than the samples of ulcerative CRC (P<0.05, respectively). Using semi-quantitative immunohistochemical analyses, S100P overexpression was found to be preferentially associated with polypoid CRC (24/30 vs. 14/40, P<0.001). The relative methylation level determined by MSP did not differ significantly between the samples of polypoid and ulcerative CRC (43.36 vs. 49.10%, P=0.168), indicating that promoter hypomethylation was not directly related to the upregulation of S100P mRNA. Our results demonstrate that the upregulation of S100P mRNA and protein expression is a predominant characteristic in polypoid CRC, whereas ulcerative CRC presents with a wide range of expression levels, indicating that S100P overexpression is not a key determinant in conferring invasion properties. The clinicopathological significance of S100P in CRC requires further investigation in well-controlled studies.

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The primary objective of this study was to determine the maximum tolerable dose (MTD) and dose-limiting toxicity (DLT) for bolus 5-fluorouracil (5-FU) administered on a biweekly schedule and in combination with fixed doses of leucovorin (LV) and oxaliplatin. The secondary objectives were to evaluate the toxicity profile and antitumor activity of this regimen for pre-treated patients with advanced colorectal cancer. A total of 26 patients with documented fluoropyrimidine-resistant, advanced colorectal cancer were enrolled into this phase I study. Fixed dose of oxaliplatin (85 mg/m2) was delivered as an i.v. infusion over 2 h, followed by LV (20 mg/m2) and 5-FU bolus every 2 weeks. The starting dose of 5-FU was 600 mg/m2, which was then incremented by 100 mg/m2 for each dose level. The DLT was determined for the first two treatment cycles, while toxicity and efficacy were evaluated throughout treatment. Six dose levels were tested. The MTD of 5-FU was deemed to be 1000 mg/m2 since dose-limiting fatigue was noted for three of the five-patient cohort during the first two cycles of chemotherapy at dose level 6. The most frequent treatment-related toxicities during the study were neutropenia, vomiting, diarrhea, fatigue and neuropathy. In an intent-to-treat analysis, the objective response rate was 30.8% (95% confidence interval 11.8-49.8%) for the 26 patients. The combination of bolus 5-FU/LV and oxaliplatin every 2 weeks is a feasible and effective treatment at the recommended dosages. A phase II study, to more-precisely define activity and toxicity, is ongoing.