Management of advanced colorectal cancer: state of the art

Local administration of irinotecan using an implantable drug delivery device stops high-grade glioma tumor recurrence in a glioblastoma tumor model

The treatment for Glioblastoma is limited due to the presence of the blood brain barrier, which restricts the entry of chemotherapeutic drugs into the brain. Local delivery into the tumor resection margin has the potential to improve efficacy of chemotherapy. We developed a safe and clinically translatable irinotecan implant for local delivery to increase its efficacy while minimizing systemic side effects. Irinotecan-loaded implants were manufactured using hot melt extrusion, gamma sterilized at 25 kGy, and characterized for their irinotecan content, release, and drug diffusion. Their therapeutic efficacy was evaluated in a patient-derived xenograft mouse resection model of glioblastoma. Their safety and translatability were evaluated using histological analysis of brain tissue and serum chemistry analysis. Implants containing 30% and 40% w/w irinotecan were manufactured without plasticizer. The 30% and 40% implants showed moderate local toxicity up to 2- and 6-day post-implantation. Histopathology of the implantation site showed signs of necrosis at days 45 and 14 for the 30% and 40% implants. Hematological analysis and clinical chemistry showed no signs of serious systemic toxicity for either implant. The 30% implants had an 80% survival at day 148, with no sign of tumor recurrence. Gamma sterilization and 12-month storage had no impact on the integrity of the 30% implants. This study demonstrates that the 30% implants are a promising novel treatment for glioblastoma that could be quickly translated into the clinic.

Local Delivery of Irinotecan to Recurrent GBM Patients at Reoperation Offers a Safe Route of Administration

Glioblastomas are impossible to completely resect and almost always recur at the borders of the resection margin. There is no established chemotherapy regimen available to patients who recur, while systemic treatment is hampered by the blood-brain barrier. Here, we report on the first evaluation in humans of the intraparenchymal injection of irinotecan into the resection cavity after surgical resection of recurrent glioblastoma patients. The cytotoxicity of irinotecan was compared to SN-38 in primary cells from recurrent glioblastoma patients. Irinotecan was injected at multiple (~30) sites of the resection cavity wall at a depth of 3 to 5 mm. SN-38 was more cytotoxic than irinotecan at concentrations below 1 µM due to enzyme kinetics. The intraparenchymal administration of irinotecan was safe, with good wound healing and an absence of swelling, inflammation, or pseudo-abscess formation. The median survival post irinotecan administration was 32.6 weeks. The median overall survival was 30.5 months, with a two-year survival rate of 56%. This study demonstrates that local delivery of irinotecan into the brain parenchyma offers a safe route of administration over systemic delivery in the treatment of recurrent glioblastoma.

Surrogacy of Recurrence-free Survival for Overall Survival as an Endpoint of Clinical Trials of Perioperative Adjuvant Therapy in Hepatobiliary-pancreatic Cancers: A Retrospective Study and Meta-analysis

OBJECTIVE

To assess the correlation between recurrence-free survival (RFS) and overall survival (OS) in the hepatobiliary-pancreatic (HBP) surgical setting to validate RFS as a surrogate endpoint.

BACKGROUND

Reliable surrogate endpoints for OS are still limited in the field of HBP surgery.

METHODS

We analyzed patients who underwent curative resection for HBP disease [986 patients with pancreatic ductal adenocarcinoma (PDAC), 1168 with biliary tract cancer (BTC), 1043 with hepatocellular carcinoma, and 1071 with colorectal liver metastasis] from September 2002 to June 2022. We also conducted meta-analyses of randomized controlled trials of neoadjuvant or adjuvant therapy to validate the surrogacy in PDAC and BTC.

RESULTS

Correlation coefficients between RFS and OS were low for hepatocellular carcinoma ( p = 0.67) and colorectal liver metastasis ( p = 0.53) but strong for PDAC ( p = 0.80) and BTC ( p = 0.75). In a landmark analysis, the concordance rates between survival or death at 5 years postoperatively and the presence or absence of recurrence at each time point (1, 2, 3, and 4 years) were 50%, 70%, 74%, and 77% for PDAC and 54%, 67%, 73%, and 78% for BTC, respectively, both increasing and reaching a plateau at 3 years. In a meta-analysis, the correlation coefficients for the RFS hazard ratio and OS hazard ratio in PDAC and BTC were p = 0.88 ( P < 0.001) and p = 0.87 ( P < 0.001), respectively.

CONCLUSIONS

Three-year RFS can be a reliable surrogate endpoint for OS in clinical trials of neoadjuvant or adjuvant therapy for PDAC and BTC.

Napabucasin Plus FOLFIRI in Patients With Previously Treated Metastatic Colorectal Cancer: Results From the Open-Label, Randomized Phase III CanStem303C Study

PURPOSE

Napabucasin is an investigational, orally administered reactive oxygen species generator bioactivated by intracellular antioxidant NAD(P)H:quinone oxidoreductase 1 that has been evaluated in various solid tumors, including metastatic colorectal cancer (mCRC). Phosphorylated signal transducer and activator of transcription 3 (pSTAT3) is hypothesized to predict response in napabucasin-treated patients with mCRC.

PATIENT AND METHODS

In the multi-center, open-label, phase III CanStem303C (NCT02753127) study, adults with histologically confirmed mCRC that progressed on first-line fluoropyrimidine plus oxaliplatin ± bevacizumab were randomized to twice-daily napabucasin plus FOLFIRI (napabucasin) or FOLFIRI alone (control). The primary endpoint was overall survival (OS) in the general study population and in patients with pSTAT3-positive tumors (biomarker-positive).

RESULTS

In the general study population (napabucasin, n = 624; control, n = 629), median OS was 14.3 months for napabucasin and 13.8 months for control (hazard ratio [HR], 0.976, one-sided P = .74). Overall, 44% of patients were biomarker-positive (napabucasin, n = 275; control, n = 272). In the biomarker-positive population, median OS was 13.2 months for napabucasin and 12.1 months for control (HR, 0.969; one-sided P > .99). In the control arm, median OS was shorter for biomarker-positive versus biomarker negative patients (12.1 vs. 18.5 months; HR, 1.518; nominal 2-sided P = .0002). The most common treatment-emergent adverse events (TEAEs) were diarrhea (napabucasin, 84.6%; control, 53.9%), nausea (60.5%, 50.5%), vomiting (41.2%, 29.3%), and abdominal pain (41.0%, 25.2%). Grade ≥3 TEAEs occurred in 73.8% of napabucasin-treated and 66.7% of control-treated patients, most commonly diarrhea (21.2%, 7.0%), neutrophil count decreased (13.7%, 19.2%), and neutropenia (13.3%, 15.2%). Safety was similar in biomarker-positive patients.

CONCLUSION

In patients with previously treated mCRC, adding napabucasin to FOLFIRI did not improve OS. Results from the control arm indicate that pSTAT3 is an adverse prognostic factor in mCRC.

Safety and Activity of PolyPEPI1018 Combined with Maintenance Therapy in Metastatic Colorectal Cancer: an Open-Label, Multicenter, Phase Ib Study

PURPOSE

Although chemotherapy is standard of care for metastatic colorectal cancer (mCRC), immunotherapy has no role in microsatellite stable (MSS) mCRC, a "cold" tumor. PolyPEPI1018 is an off-the-shelf, multi-peptide vaccine derived from 7 tumor-associated antigens (TAA) frequently expressed in mCRC. This study assessed PolyPEPI1018 combined with first-line maintenance therapy in patients with MSS mCRC.

PATIENTS AND METHODS

Eleven patients with MSS mCRC received PolyPEPI1018 and Montanide ISA51VG adjuvant subcutaneously, combined with fluoropyrimidine/biologic following first-line induction with chemotherapy and a biologic (NCT03391232). In Part A of the study, 5 patients received a single dose; in Part B, 6 patients received up to three doses of PolyPEPI1018 every 12 weeks. The primary objective was safety; secondary objectives were preliminary efficacy, immunogenicity at peripheral and tumor level, and immune correlates.

RESULTS

PolyPEPI1018 vaccination was safe and well tolerated. No vaccine-related serious adverse event occurred. Eighty percent of patients had CD8+ T-cell responses against ≥3 TAAs. Increased density of tumor-infiltrating lymphocytes were detected post-treatment for 3 of 4 patients' liver biopsies, combined with increased expression of immune-related gene signatures. Three patients had objective response according to RECISTv1.1, and 2 patients qualified for curative surgery. Longer median progression-free survival for patients receiving multiple doses compared with a single dose (12.5 vs. 4.6 months; P = 0.017) suggested a dose-efficacy correlation. The host HLA genotype predicted multi-antigen-specific T-cell responses (P = 0.01) indicative of clinical outcome.

CONCLUSIONS

PolyPEPI1018 added to maintenance chemotherapy for patients with unresectable, MSS mCRC was safe and associated with specific immune responses and antitumor activity warranting further confirmation in a randomized, controlled setting.

Patient-Derived Organoid Serves as a Platform for Personalized Chemotherapy in Advanced Colorectal Cancer Patients

Background

Addition of oxaliplatin to adjuvant 5-FU has significantly improved the disease-free survival and served as the first line adjuvant chemotherapy in advanced colorectal cancer (CRC) patients. However, a fraction of patients remains refractory to oxaliplatin-based treatment. It is urgent to establish a preclinical platform to predict the responsiveness toward oxaliplatin in CRC patients as well as to improve the efficacy in the resistant patients.

Methods

A living biobank of organoid lines were established from advanced CRC patients. Oxaliplatin sensitivity was assessed in patient-derived tumor organoids (PDOs) in vitro and in PDO-xenografted tumors in mice. Based on in vitro oxaliplatin IC₅₀ values, PDOs were classified into either oxaliplatin-resistant (OR) or oxaliplatin-sensitive (OS) PDOs. The outcomes of patients undergone oxaliplatin-based treatment was followed. RNA-sequencing and bioinformatics tools were performed for molecular profiling of OR and OS PDOs. Oxaliplatin response signatures were submitted to Connectivity Map algorithm to identify perturbagens that may antagonize oxaliplatin resistance.

Results

Oxaliplatin sensitivity in PDOs was shown to correlate to oxaliplatin-mediated inhibition on PDO xenograft tumors in mice, and parallelled clinical outcomes of CRC patients who received FOLFOX treatment. Molecular profiling of transcriptomes revealed oxaliplatin-resistant and -sensitive PDOs as two separate entities, each being characterized with distinct hallmarks and gene sets. Using Leave-One-Out Cross Validation algorithm and Logistic Regression model, 18 gene signatures were identified as predictive biomarkers for oxaliplatin response. Candidate drugs identified by oxaliplatin response signature-based strategies, including inhibitors targeting c-ABL and Notch pathway, DNA/RNA synthesis inhibitors, and HDAC inhibitors, were demonstrated to potently and effectively increase oxaliplatin sensitivity in the resistant PDOs.

Conclusions

PDOs are useful in informing decision-making on oxaliplatin-based chemotherapy and in designing personalized chemotherapy in CRC patients.

Identification of a subpopulation of long-term tumor-initiating cells in colon cancer

Long-term tumor-initiating cells (LT-TICs) are viewed as a quantifiable target for colon cancer therapy owing to their extensive self-renewal and tumorigenic and metastatic capacities. However, it is unknown which subpopulation of colon cancer cells contains LT-TICs. Here, based on the methods for isolating and identifying cancer stem cells (CSCs) and the functional features of LT-TICs, we aimed to identify a subpopulation of LT-TICs. Among the six cell lines assessed, our results showed that CD133 and CD44 coexpression was only detected in HCT116 and HT29 cell lines. In HCT116 and HT29 cells, CD133⁺CD44⁺ cells not only shared the extensive tumorigenic potential of LT-TICs but also functionally reproduced the behaviors of LT-TICs that drive tumor metastasis (TM) formation, suggesting that CD133⁺CD44⁺ cells are a typical representation of LT-TICs in colon cancer. Mechanistically, the enhanced capacity of CD133⁺CD44⁺ cells to drive metastasis involves the up-regulated expression of Wnt-, epithelial–mesenchymal transition (EMT)-, and metastasis-related genes in these cells. Additionally, CD133⁺CD44⁺ cells presented significant chemoresistance compared with corresponding nontumorigenic CD133⁻CD44⁻ cells following exposure to oxaliplatin (OXLP) or 5-fluorouracil (5-FU). Accordingly, CD133⁺CD44⁺ cells contained lower reactive oxygen species (ROS) levels than CD1133⁻CD44⁻ cells, and the low ROS levels in CD133⁺CD44⁺ cells were related to the enhancement of antioxidant defense systems. More importantly, CD133⁺CD44⁺ cells developed less DNA damage after exposure to chemotherapeutics than CD133⁻CD44⁻ cells. In conclusion, we identified a subpopulation of LT-TICs in colon cancer.

Development and in vivo evaluation of Irinotecan-loaded Drug Eluting Seeds (iDES) for the localised treatment of recurrent glioblastoma multiforme

Glioblastoma multiforme (GBM) is impossible to fully remove surgically and almost always recurs at the borders of the resection cavity, while systemic delivery of therapeutic drug levels to the brain tumour is limited by the blood-brain barrier. This research describes the development of a novel formulation of Irinotecan-loaded Drug Eluting Seeds (iDES) for insertion into the margin of the GBM resection cavity to provide a sustained high local dose with reduced systemic toxicities. We used primary GBM cells from both the tumour core and Brain Around the Tumour tissue from recurrent GBM patients to demonstrate that irinotecan is more effective than temozolomide. Irinotecan had a 75% response rate, while only 50% responded to temozolomide. With temozolomide the cell viability was never below 80% whereas irinotecan achieved cell viabilities of less than 44%. The iDES were manufactured using a hot melt extrusion process with accurate irinotecan drug loadings and the same cytotoxicity as unformulated irinotecan. The iDES released irinotecan in a sustained fashion for up to 7 days. However, only the 30, 40 and 50% w/w loaded iDES formulations released the 300 to 1000 μg of irinotecan needed to be effective in vivo. The 30 and 40% w/w iDES formulations containing 10% plasticizer and either 60 or 50% PLGA prolonged survival from 27 to 70 days in a GBM xenograft mouse resection model with no sign of tumour recurrence. The 30% w/w iDES formulations showed equivalent toxicity to a placebo in non-tumour bearing mice. This innovative drug delivery approach could transform the treatment of recurrent GBM patients by improving survival and reducing toxicity.

Efficacy and safety of anti-EGFR monoclonal antibodies combined with different chemotherapy regimens in patients with RAS wild-type metastatic colorectal cancer: A meta-analysis

OBJECTIVES

To investigate the efficacy and safety of adding anti-epidermal growth factor receptor [EGFR] MoAbs to various chemotherapy regimens in patients with RAS wild-type metastasized colorectal cancer (RAS WT metastatic colorectal cancer [mCRC]) and to identify the optimal combination regimens.

METHODS

We searched MEDLINE, EMBASE, and CENTRAL from the inception date to 20th May 2019. Randomized clinical trials investigating chemotherapy with or without anti-EGFR MoAbs in treatment of patients with RAS WT mCRC were included.

RESULTS

Eighteen studies involving 8848 participants were eligible. Comparing with oxaliplatin-based chemotherapy, adding anti-EGFR MoAbs benefited only in progression-free survival (PFS) (hazard ratio [HR] = 0.80, 95% confidence interval [CI]: 0.67 to 0.94), but not in overall survival (OS) (HR = 0.89, 95% CI: 0.78 to 1.02). Further sensitivity analysis indicated that adding anti-EGFR MoAbs to FOLFOLX regimen as a first-line treatment showed benefits in both PFS and OS (PFS: HR = 0.74, 95% CI: 0.64 to 0.84; OS: HR = 0.83, 95% CI: 0.73 to 0.95, respectively). Comparing with irinotecan-based chemotherapy or best supportive care, adding anti-EGFR MoAbs revealed an improvement in both PFS (HR = 0.77, 95% CI: 0.69 to 0.86; HR = 0.46, 95% CI: 0.40 to 0.54, respectively) and OS (HR = 0.89, 95% CI: 0.80 to 0.98; HR = 0.65, 95% CI: 0.54 to 0.78, respectively).

CONCLUSION

Anti-EGFR MoAbs as a monotherapy or in combination with either irinotecan-based chemotherapy or FOLFOX in patients with RAS wild-type mCRC have better response and survival outcome, whereas OS does not benefit from adding anti-EGFR MoAbs to another oxaliplatin-based regimen. Anti-EGFR MoAbs have increased the risk of adverse effects than chemotherapy alone. More high-quality randomized controlled trials for RAS wild type are necessary.

Lupeol inhibits growth and migration in two human colorectal cancer cell lines by suppression of Wnt-β-catenin pathway

Background

Lupeol, a triterpene isolated from various herbal plants, possesses an anti-inflammatory function and has been proposed as a candidate for anticancer agents. The purpose of this research was to investigate the effect of lupeol on the viability, apoptosis, cell-cycle distribution, and migration of colorectal cancer cell lines and its molecular mechanism.

Methods

Lupeol was assessed for its anticancer effect using two human colorectal cancer cell lines: SW480 and HCT116. These cells were treated with lupeol, and their viability, apoptosis, migration, and cycle distribution were detected by CCK8, flow cytometry, and the transwell method. Quantitative PCR, Western blot, and immunofluorescence were applied to detect the expressions of CTNNB1, TCF4, cMYC, CCND1, CLDN1, and CCNA2.

Results

Lupeol suppressed cell viability and migration and induced cellular apoptosis of both cell lines, with increased p53 and decreased Bcl2 protein levels (P<0.05). Cell cycles of both lupeol-treated cell lines were arrested in the S phase (P<0.05). Quantitative PCR and Western blot analyses showed significantly reduced expressions of CTNNB1, TCF4, and downstream genes of the Wnt–β-catenin pathway, including the cell-cycle-regulated genes of cMYC and CCND1 of both cell lines upon lupeol treatment (P<0.05). mRNA and protein levels of CLDN1 decreased in HCT116 cells, plus the expression of CCNA2 mRNA and protein decreased in SW480 cells (P<0.05). Immunofluorescence analysis confirmed decreased expression of Wnt–β-catenin signaling.

Conclusion

Our findings indicate that lupeol effectively inhibits proliferation and migration and induces apoptosis and cell-cycle arrest of two colorectal cell lines by inactivation of the Wnt–β-catenin signaling pathway and downregulation of cMYC, CCND1, CCNA2, and CLDN1, thereby making it a promising anticancer candidate.

Omega-3 fatty acid DHA modulates p53, survivin, and microRNA-16-1 expression in KRAS-mutant colorectal cancer stem-like cells

Background

The presence of chemotherapy-resistant colorectal cancer stem cells (CCSCs) with KRAS mutation is thought to be one of the primary causes for treatment failure in colorectal cancer (CRC). P53, survivin, and microRNA-16-1 are challenging targets for anticancer drugs which are associated with chemoresistance in CRC. Yet, no p53-, survivin-, and microRNA-16-1-modulating drug with low toxicity but high efficacy against KRAS-mutant CCSCs have been approved for clinical application in CRC. Here, we investigated whether in vitro concentrations of DHA equal to human plasma levels, are able to modulate, Wt-p53, survivin, and microRNA-16-1 in CRC cells with stem cell-like properties.

Methods

Wt-p53/KRAS-mutant CRC cells (HCT-116) with stem cell-like properties were treated with 100-, 150- and 200-μM/L DHA, after which cell number, viability, growth inhibition, Wt-p53, survivin and microRNA-16-1 expression, caspase-3 activation and apoptotic-rate were evaluated by different cellular and molecular techniques.

Results

After 24-, 48-, and 72-h treatments with 100- to 200-μM/L DHA, growth inhibition- rates were measured to be 54.7% to 59.7%, 73.% to 75.8%, and 63.3% to 97.7%, respectively. Treatment for 48 h with indicated DHA concentrations decreased cell number and viability. In addition, we observed a decrease in both the transcript and protein levels of survivin followed by 1.3- to 1.7- and 1.1- to 4.7-fold increases in the Wt-p53 accumulation and caspase-3 activation levels respectively. Treatment with 100 and 150 μM/L DHA increased microRNA-16-1 expression levels by 1.3- to 1.7-fold and enhanced the microRNA-16-1/survivin mRNA, p53/survivin, and caspase-3/survivin protein ratios by 1.7- to 1.8-, 1.3- to 2.6-, and 1.3- to 2-fold increases respectively. A decrease in the number of live cells and an increase in the number of apoptotic cells were also observed with increasing DHA concentrations.

Conclusion

Wt-p53, survivin, and microRNA-16-1 appear to be promising molecular targets of DHA. Thus, DHA might represent an attractive anti-tumor agent directed against KRAS-mutant CCSCs.

Silencing Livin improved the sensitivity of colon cancer cells to 5-fluorouracil by regulating crosstalk between apoptosis and autophagy

Colorectal cancer (CRC) is the third most common cause of cancer-associated mortality worldwide. Currently, 5-fluorouracil (5-FU) remains a widely used chemotherapeutic drug in the treatment of CRC; however, 5-FU resistance during treatment has become a common problem. Livin, a member of the inhibitor of apoptosis protein family, is considered to be associated with tumor resistance to chemotherapy. In the present study, Livin-silenced cells were generated by introducing a lentivirus into HCT116 and SW620 colon cancer cell lines. Acridine orange/ethidium bromide staining was used as an indicator of cell death. Western blot analysis was performed to detect protein expression levels, and transmission electron microscopy was used to assess autophagy. The half-maximal inhibitory concentration of 5-FU in colon cancer cells was evaluated using a Cell Counting Kit-8 assay. The results of the present study confirmed that silencing Livin significantly enhanced colon cancer cell death in the presence of 5-FU, increased expression levels of various apoptosis- and autophagy-associated proteins and augmented chemotherapeutic sensitivity to 5-FU. Furthermore, the present study demonstrated that this effect may be reversed when autophagy or apoptosis was inhibited, indicating that apoptosis and autophagy were involved in this process. The protein kinase B signaling pathway and B-cell lymphoma-2 expression levels significantly decreased following Livin knockdown, suggesting they may contribute to the regulation of apoptosis and autophagy crosstalk, which caused the Livin knockdown-induced cell death observed.

Potential Role of Single Nucleotide Polymorphisms of XRCC1, XRCC3, and RAD51 in Predicting Acute Toxicity in Rectal Cancer Patients Treated With Preoperative Radiochemotherapy

OBJECTIVES

To investigate the association between polymorphisms of DNA repair genes and xenobiotic with acute adverse effects in locally advanced rectal cancer patients treated with neoadjuvant radiochemotherapy.

METHODS

Sixty-seven patients were analyzed for the current study. Genotypes in DNA repair genes XRCC1 (G28152A), XRCC3 (A4541G), XRCC3 (C18067T), RAD51 (G315C), and GSTP1 (A313G) were determined by pyrosequencing technology.

RESULTS

The observed grade ≥3 acute toxicity rates were 23.8%. Chemotherapy and radiotherapy were interrupted for 46 and 14 days, respectively, due to critical complications. Four patients were hospitalized, 6 patients had been admitted to the ER, and 5 patients received invasive procedures (2 bladder catheters, 2 blood transfusions, and 1 growth factor therapy).RAD51 correlated with acute severe gastrointestinal toxicity in heterozygosity (Aa) and homozygosity (AA) (P=0.036). Grade ≥3 abdominal/pelvis pain toxicity was higher in the Aa group (P=0.017) and in the Aa+AA group (P=0.027) compared with homozygous (aa) patients. Acute skin toxicity of any grade occurred in 55.6% of the mutated patients versus 22.8% in the wild-type group (P=0.04) for RAD51. XRCC1 correlated with skin toxicity of any grade in the Aa+AA group (P=0.03) and in the Aa group alone (P=0.044). Grade ≥3 urinary frequency/urgency was significantly higher in patients with AA (P=0.01), Aa (P=0.022), and Aa+AA (P=0.031) for XRCC3 compared with aa group.

CONCLUSIONS

Our study suggested that RAD51, XRCC1, and XRCC3 polymorphisms may be predictive factors for radiation-induced acute toxicity in rectal cancer patients treated with preoperative combined therapy.

Second-line systemic therapy for metastatic colorectal cancer

BACKGROUND

The therapeutic management of people with metastatic colorectal cancer (CRC) who did not respond to first-line treatment represents a formidable challenge.

OBJECTIVES

To determine the efficacy and toxicity of second-line systemic therapy in people with metastatic CRC.

SEARCH METHODS

We searched the Cochrane Central Register of Controlled Trials (CENTRAL) (the Cochrane Library 2016, Issue 4), Ovid MEDLINE (1950 to May 2016), Ovid MEDLINE In-process & Other Non-Indexed Citations (1946 to May 2016) and Ovid Embase (1974 to May 2016). There were no language or date of publication restrictions.

SELECTION CRITERIA

Randomized controlled trials (RCTs) assessing the efficacy (survival, tumour response) and toxicity (incidence of severe adverse effects (SAEs)) of second-line systemic therapy (single or combined treatment with any anticancer drug, at any dose and number of cycles) in people with metastatic CRC that progressed, recurred or did not respond to first-line systemic therapy.

DATA COLLECTION AND ANALYSIS

Authors performed a descriptive analysis of each included RCT in terms of primary (survival) and secondary (tumour response, toxicity) endpoints. In the light of the variety of drug regimens tested in the included trials, we could carry out meta-analysis considering classes of (rather than single) anticancer regimens; to this aim, we applied the random-effects model to pool the data. We used hazard ratios (HRs) and risk ratios (RRs) to describe the strength of the association for survival (overall (OS) and progression-free survival (PFS)) and dichotomous (overall response rate (ORR) and SAE rate) data, respectively, with 95% confidence intervals (CI).

MAIN RESULTS

Thirty-four RCTs (enrolling 13,787 participants) fulfilled the eligibility criteria. Available evidence enabled us to address multiple clinical issues regarding the survival effects of second-line systemic therapy of people with metastatic CRC.1. Chemotherapy (irinotecan) was more effective than best supportive care (HR for OS: 0.58, 95% CI 0.43 to 0.80; 1 RCT; moderate-quality evidence); 2. modern chemotherapy (FOLFOX (5-fluorouracil plus leucovorin plus oxaliplatin), irinotecan) is more effective than outdated chemotherapy (5-fluorouracil) (HR for PFS: 0.59, 95% CI 0.49 to 0.73; 2 RCTs; high-quality evidence) (HR for OS: 0.69, 95% CI 0.51 to 0.94; 1 RCT; moderate-quality evidence); 3. irinotecan-based combinations were more effective than irinotecan alone (HR for PFS: 0.68, 95% CI 0.60 to 0.76; 6 RCTs; moderate-quality evidence); 4. targeted agents improved the efficacy of conventional chemotherapy both when considered together (HR for OS: 0.84, 95% CI 0.77 to 0.91; 6 RCTs; high-quality evidence) and when bevacizumab was used alone (HR for PFS: 0.67, 95% CI 0.60 to 0.75; 4 RCTs; high-quality evidence).With regard to secondary endpoints, tumour response rates generally paralleled the survival results; moreover, higher anticancer efficacy was generally associated with worse treatment-related toxicity, with the important exception of bevacizumab-containing regimens, where the addition of the targeted agent to chemotherapy did not result in a significant increase in the rate of SAE. Finally, we found that oral (instead of intravenous) fluoropyrimidines significantly reduced the incidence of adverse effects (without compromising efficacy) in people treated with oxaliplatin-based regimens.We could not draw any conclusions on other debated aspects in this field of oncology, such as ranking of treatments (not all possible comparisons have been tested and many comparisons were based on single trials enrolling a small number of participants) and quality of life (virtually no data available).

AUTHORS' CONCLUSIONS

Systemic therapy offers a survival benefit to people with metastatic CRC who did not respond to first-line treatment, especially when targeted agents are combined with conventional chemotherapeutic drugs. Further research is needed to define the optimal regimen and to identify people who most benefit from each treatment.

Effective Targeting Survivin, Caspase-3 and MicroRNA-16-1 Expression by Methyl-3-pentyl-6-methoxyprodigiosene Triggers Apoptosis in Colorectal Cancer Stem-Like Cells

Over-expression of the proto-oncogene survivin in colorectal cancer stem cells (CCSCs) is thought to be one the primary causes for therapy failure. It has also been reported that tumor suppressor miR-16-1 is down-regulated in colorectal cancer (CRC) cells. Therefore, the search for new anti-proliferative agents which target survivin or miR-16-1 in CCSCs is warranted. Several studies have shown that prodigiosin isolated from cell wall of Serratia marcescens induces apoptosis in different kinds of cancer cells. Here, we investigated the effects of prodigiosin on HCT-116 cells that serve as a model for CRC initiating cells with stem-like cells properties. HCT-116 cells were treated with 100, 200 and 400 nM prodigiosin after which cell number, viability, growth-rate, survivin and miRNA-16-1 expression, caspase-3 activation and apoptotic rate were evaluated. Prodigiosin decreased significantly growth-rate in a dose-and time-dependent manner. After a 48 h treatment with 100, 200 and 400 nM prodigiosin, growth-rates were measured to be 84.4 ± 9.2 %, 58 ± 6.5 % and 46.3 ± 5.2 %, respectively, compared to untreated cells. We also found that treatment for 48 h with indicated concentrations of prodigiosin resulted in 41 %, 54.5 % and 63 % decrease in survivin mRNA levels and induced 32 %, 48 % and 61 % decrease in survivin protein levels as well as resulted in 128.3 ± 10 %, 178.7 ± 6.1 % and 205 ± 7.6 % increase in caspase-3 activation respectively compared to untreated cells. Prodigiosin caused a significant increase in miRNA-16-1 expression at a concentration of 100 nM and treatment with different concentrations of prodigiosin resulted in 2.2- to 3-fold increase in miRNA-16-1/survivin ratios compared to untreated cells. An increase in number of apoptotic cells ranging from 28.2 % to 86.8 % was also observed with increasing prodigiosin concentrations. Our results provide the first evidence that survivin and miRNA-16-1 as potential biomarkers could be targeted in CRC initiating cells with stem-like cells properties by prodigiosin and this compound with high pro-apoptotic capacity represents the possibility of its therapeutic application directed against CCSCs.

Clinical Implication of UGT1A1 Promoter Polymorphism for Irinotecan Dose Escalation in Metastatic Colorectal Cancer Patients Treated with Bevacizumab Combined with FOLFIRI in the First-line Setting

PURPOSE: This study aimed to identify the efficacy and toxicity of the FOLFIRI regimen (fluorouracil, leucovorin, and irinotecan) with irinotecan dose escalation plus bevacizumab as first-line chemotherapy for metastatic colorectal cancer (mCRC) via UGT1A1 genotyping. METHODS: We administered bevacizumab plus FOLFIRI with irinotecan dose escalation to treat 70 mCRC patients. The UGT1A1 *1/*1 and *1/*28 genotypes started with a 180-mg/m² dose of irinotecan, and UGT1A1 *28/*28 genotype started with a dose of 120 mg/m². The dose of irinotecan was escalated at increasing intervals of 20 to 30 mg/m² until grade 3/4 adverse events (AEs) occurred. The clinical response rate, toxicity, and survival were analyzed. RESULTS: The clinical response and disease control rates of mCRC patients treated with FOLFIRI plus bevacizumab were significantly better in patients with UGT1A1 *1/*1 and *1/*28 genotypes than in patients with UGT1A1 *28/*28 (P = .006 and P < .001, respectively). Grade 3/4 AEs were significantly more common in mCRC patients with the UGT1A1 *28/*28 genotype (P < .001). Progression-free survival was significantly higher in UGT1A1 *1/*1 and *1/*28 patients (P = .002). mCRC patients who underwent metastasectomy achieved better overall survival than those who did not undergo metastasectomy (P = .015). CONCLUSIONS: Our study showed that mCRC patients with UGT1A1 *1/*1 and *1/*28 genotypes could receive escalated doses of irinotecan to obtain a more favorable clinical outcome without significant AEs.

Sasa quelpaertensis Leaf Extract Inhibits Colon Cancer by Regulating Cancer Cell Stemness in Vitro and in Vivo

A rare subpopulation of cancer cells, termed cancer stem cells (CSCs), may be responsible for tumor relapse and resistance to conventional chemotherapy. The development of a non-toxic, natural treatment for the elimination of CSCs is considered a strategy for cancer treatment with minimal side effects. In the present study, the potential for Sasa quelpaertensis leaf extract (SQE) and its two bioactive compounds, tricin and p-coumaric acid, to exert anti-CSC effects by suppressing cancer stemness characteristics were evaluated in colon cancer cells. CD133⁺CD44⁺ cells were isolated from HT29 and HCT116 cell lines using flow-activated cell sorting (FACs). SQE treatment was found to significantly suppress the self-renewal capacity of both cell lines. SQE treatment was also associated with the down-regulation of β-catenin and phosphorylated GSK3β, while significantly enhancing cell differentiation by up-regulating CK20 expression and blocking the expression of several stem cell markers, including DLK1, Notch1, and Sox-2. In vivo, SQE supplementation suppressed tumor growth in a xenograft model by down-regulating stem cell markers and β-catenin as well as HIF-1α signaling. Compared with two bioactive compounds of SQE, SQE exhibited the most effective anti-CSC properties. Taken together, these results provide evidence that SQE inhibits colon cancer by regulating the characteristics of CSCs.

Prognostic advantage of irinotecan dose escalation according to uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) genotyping in patients with metastatic colorectal cancer treated with bevacizumab combined with 5-fluorouracil/leucovorin with irinotecan in a first-line setting

This study compared the clinical responses of patients with metastatic colorectal cancer (mCRC) with 5-fluorouracil/leucovorin with irinotecan (FOLFIRI) plus bevacizumab therapy either with or without uridine diphosphate glucuronosyltransferase 1A1 (UGT1A1) genotyping and irinotecan dose escalation. Of 107 total patients with mCRC, 79 were classified as the study group and 28 as the control group. The study group received irinotecan dose escalation based on UGT1A1 genotyping whereas the control group did not. Clinicopathologic features, response rates, and survival were compared for the 2 groups. The clinical response rate of patients with mCRC treated with FOLFIRI plus bevacizumab under UGT1A1 genotyping and irinotecan dose escalation was significantly better than that of those without these prospective tests and dose escalation (P = 0.028). Both progression-free survival (PFS) and overall survival were significantly greater in clinical responders than nonresponders (both, P < 0.001), and PFS was significantly greater among the study group patients than among the control group patients, with a median PFS of 12.2 months vs 9.4 months (P = 0.025). Grade 3/4 adverse events were not significantly different between the 2 groups (P = 0.189). Patients with mCRC undergoing UGT1A1 genotyping may receive escalated doses of irinotecan to obtain a better clinical response/outcome with comparable toxicities.

Tumor-associated fibroblasts isolated from colorectal cancer tissues exhibit increased ICAM-1 expression and affinity for monocytes

Progression of colorectal cancer (CRC) is strongly associated with inflammation and other desmoplastic reactions in the tumor cell-surrounding tissue. We successfully isolated fibroblasts from the desmoplastic stroma of human CRC specimens and uninvolved colon tissue of patients treated surgically for CRC and investigated potential functional capacities. All of the isolated fibroblasts were vimentin-positive and CK-20/CD45-negative confirming the fibroblast phenotype. Differential expression patterns were detected between tumor-associated fibroblasts (TAFs) and normal tissue-associated fibroblasts (NAFs) regarding intercellular adhesion molecule-1 (ICAM-1) expression. In 11 of 12 TAF cultures, basal ICAM-1 expression was increased as compared to corresponding NAF cultures (p=0.001). After stimulation of the cultures with interleukin-1β, 8 of the 12 TAF cultures presented higher ICAM-1 levels when compared with the level in the corresponding NAF cultures (p=0.001). Moreover, the adhesive capacity of these cultures for U937 was increased in 8 out of 10 unstimulated and in 10 out of 10 stimulated cultures when TAFs and NAFs were compared. In corresponding tumor tissue sections from the same patients, the amount of ICAM-1-positive fibroblasts was significantly higher than that in the corresponding normal colon mucosa, indicating a tumor-specific effect that was maintained in the isolated cultures. These results indicate that fibroblasts from CRC tissue exhibit an increased affinity for monocytic cells. This increased intercellular interaction may contribute to elongated residence times of monocytes in CRC tissue. Therefore, these isolated fibroblasts are a useful tool for further functional investigation of desmoplastic tissue reactions in CRC.

Plasma microRNAs predicting clinical outcome in metastatic colorectal cancer patients receiving first-line oxaliplatin-based treatment

The conventional first-line chemotherapy for metastatic colorectal cancer (mCRC) consists of fluorouracil (5-FU) in combination with either oxaliplatin or irinotecan. We have explored microRNAs (miRNAs) in plasma as potential predictive markers to oxaliplatin-based chemotherapy. The expression of 742 miRNAs was examined in plasma samples from 24 mCRC patients (12 responders and 12 non-responders) before onset and after four cycles of 5-FU/oxaliplatin. The top differentially expressed miRNAs between responders and non-responders were selected for further analysis in a validation cohort of 150 patients. In the validation cohort, there was a significant overrepresentation of miRNAs with higher mean expression in the non-responder group than in the responder group before treatment (p < 0.002). Moreover, we found three miRNAs (miR-106a, miR-484, and miR-130b) to be significantly differentially expressed before treatment (p = 0.008, 0.008, and 0.008, respectively). All three miRNAs were upregulated in non-responders. High expression of miR-27b, miR-148a, and miR-326 were associated with decreased progression-free survival (Hazard ratios (HR) of 1.4 (95% CI 1.1-1.8, p = 0.004), 1.3 (95% CI 1.1-1.6, p = 0.007), and 1.4 (95% CI 1.1-1.8, p = 0.008), respectively). miR-326 was also associated with decreased overall survival (HR 1.5 (95% CI 1.1-2.0, p = 0.003)). There were no significantly differentially expressed miRNAs in association with clinical outcome after four cycles of chemotherapy. The present study demonstrates that plasma miRNAs analyzed before treatment may serve as non-invasive markers predicting outcome in mCRC patients treated with 5-FU and oxaliplatin-based chemotherapy.

Omega-3 eicosapentaenoic acid decreases CD133 colon cancer stem-like cell marker expression while increasing sensitivity to chemotherapy

Colorectal cancer is the third leading cause of cancer-related death in the western world. In vitro and in vivo experiments showed that omega-3 polyunsaturated fatty acids (n-3 PUFAs) can attenuate the proliferation of cancer cells, including colon cancer, and increase the efficacy of various anticancer drugs. However, these studies address the effects of n-3 PUFAs on the bulk of the tumor cells and not on the undifferentiated colon cancer stem-like cells (CSLCs) that are responsible for tumor formation and maintenance. CSLCs have also been linked to the acquisition of chemotherapy resistance and to tumor relapse. Colon CSLCs have been immunophenotyped using several antibodies against cellular markers including CD133, CD44, EpCAM, and ALDH. Anti-CD133 has been used to isolate a population of colon cancer cells that retains stem cells properties (CSLCs) from both established cell lines and primary cell cultures. We demonstrated that the n-3 PUFA, eicosapentaenoic acid (EPA), was actively incorporated into the membrane lipids of COLO 320 DM cells. 25 uM EPA decreased the cell number of the overall population of cancer cells, but not of the CD133 (+) CSLCs. Also, we observed that EPA induced down-regulation of CD133 expression and up-regulation of colonic epithelium differentiation markers, Cytokeratin 20 (CK20) and Mucin 2 (MUC2). Finally, we demonstrated that EPA increased the sensitivity of COLO 320 DM cells (total population) to both standard-of-care chemotherapies (5-Fluorouracil and oxaliplatin), whereas EPA increased the sensitivity of the CD133 (+) CSLCs to only 5-Fluorouracil.

Validation of KRAS testing for anti-EGFR therapeutic decisions for patients with metastatic colorectal carcinoma

CONTEXT

KRAS mutation status is a molecular marker for predicting patient response to treatment with anti-EGFR antibodies (cetuximab and panitumumab) in metastatic colorectal carcinoma. Different approaches may be taken to detect KRAS mutations. There currently are no US Food and Drug Administration-approved assays for the detection of KRAS mutations. For assays that are not approved by the US Food and Drug Administration, the performance characteristics of the assay must be determined and validated by the clinical laboratory before implementation.

OBJECTIVE

To provide an example of how a KRAS mutation-analysis assay may be validated in a clinical laboratory.

DESIGN

Describing the approach used by an individual laboratory to compare different assays for validation of KRAS mutation analysis in metastatic colon carcinoma.

RESULTS

Specific validation data are provided, illustrating how a laboratory established assay performance characteristics for KRAS mutation analysis.

CONCLUSIONS

All clinical laboratories must establish several performance specifications mandated by the Clinical Laboratory Improvement Amendments of 1988 before implementation of any laboratory-developed test. Approaches to the validation of such assays may vary among laboratories. We describe an approach used for validation of a KRAS mutation-analysis assay by one laboratory.

Despite aggressive histopathology survival is not impaired in young patients with colorectal cancer : CRC in patients under 50 years of age

PURPOSE

Colorectal carcinoma (CRC) is generally a disease of persons older than 50 years. Concerning younger patients, controversies still exist regarding features and prognosis of CRC. We performed this study to characterize CRC in young patients (≤50 years) as well as to evaluate outcome in comparison with older patients (>50 years) with CRC.

METHODS

Clinical and histopathological parameters of 244 patients aged 50 years or less were compared with 1,718 patients aged more than 50 years.

RESULTS

Compared with older patients, the younger had less adenocarcinomas (82.8% vs. 89.1%; p = 0.004) and less postoperative complications (18.4% vs. 28.7%; p = 0.001), and less Union Internationale Contre le Cancer stage I colon cancers (22.9% vs. 13.6%, p = 0.046) but elevated overall 5-year survival rates for M0 colon and rectal cancers (p = 0.005; p < 0.001). In young patients, the minority suffered from hereditary cancer syndromes (7.4%) and inflammatory bowel diseases (7.0%). Furthermore, up to 40% of young patients denied any cancers in their families. Cancer-related survival rates were significantly elevated in young patients with M0 rectal carcinoma (p = 0.014), whereas in M0 colon cancers, no differences were detectable (p = 0.542). In case of the presence of distant metastases, overall and cancer-related survival rates were similar in old and young patients.

CONCLUSION

Although young patients present with more aggressive histopathological subtypes and less early stages, cancer-related survival is not less favourable compared with older patients.

Is coagulation factor VIII a useful marker for colorectal carcinoma?

BACKGROUND AND OBJECTIVE

Increased thromboembolic events are well known in patients suffering from malignant diseases. In the following pilot study, we investigated the usefulness of coagulation factor VIII (FVIII) as a possible prognostic marker in patients with colorectal carcinoma (CRC).

METHODS

Plasma FVIII levels were measured in 79 patients with CRC, correlated with tumor characteristics, and compared with normal ranges of blood group (BG) 0 and BG A/AB/B and with 19 control patients.

RESULTS

In CRC patients mean FVIII levels were elevated compared with controls (BG 0: p=0.283, BG A/AB/B: p=0.001) and normal ranges. Interestingly, mean FVIII levels varied significantly in different blood groups (p=0.002). UICC stage I CRC patients presented with mean FVIII plasma levels within normal ranges, whereas UICC stage II-IV CRC patients presented with elevated FVIII plasma levels. In BG A/AB/B a significantly elevated FVIII level was found in G2 compared with G1 tumors (p< 0.001). Patients with elevated carcinoembryonic antigen also showed significantly elevated FVIII levels (p=0.050). FVIII levels at time of surgery did not correlate with survival within the first 2 years following surgery.

CONCLUSION

In this pilot study, we demonstrated that FVIII plasma levels are elevated in patients with CRC and affected by T-stage and differentiation of the tumor. Whether FVIII is a clinical useful marker needs to be tested in a larger cohort.

Prognostic value of reduced SMAD4 expression in patients with metastatic colorectal cancer under oxaliplatin-containing chemotherapy: a translational study of the AIO colorectal study group

BACKGROUND

SMAD4 is a polypeptide with tumor suppressor function being investigated as a prognostic biomarker in Union Internationale Contre le Cancer stages II and III in previous studies, but its role as a prognostic marker in stage IV colorectal cancer (CRC) is still undefined. We investigated the prognostic value of reduced SMAD4 expression in patients with metastatic (mCRC) under first-line oxaliplatin-containing combination chemotherapy.

PATIENTS AND METHODS

Tumor samples were obtained from patients who took part in a prospective randomized phase III chemotherapy trial of the Arbeitsgemeinschaft Internistische Onkologie of the German Cancer Society colorectal study group, comparing the use of capecitabine plus oxaliplatin with infusional 5-fluorouracil (5-FU) plus oxaliplatin as first-line therapy in mCRC. SMAD4 expression was determined by immunohistochemistry.

RESULTS

Tumor tissues from 230 patients were obtained. Reduced SMAD4 expression was identified in 34% of samples. Patients with reduced nuclear SMAD4 expression in tumor tissue showed a shorter progression-free survival (PFS; 7.0 months vs. 8.9 months; P = .024) and overall survival (OS; 13.9 months vs. 17.8 months; P = .044) compared with patients retaining SMAD4 expression. The effect of SMAD4 expression on PFS and OS could be demonstrated in univariate and multivariate analyses.

CONCLUSION

Our data demonstrate the importance of reduced SMAD4 expression in patients with mCRC receiving chemotherapy with oxaliplatin and 5-FU.

The clinical value of von Willebrand factor in colorectal carcinomas

BACKGROUND

To identify the value of von Willebrand factor (vWF) as a clinical marker in colorectal carcinoma (CRC).

METHODS

Plasma levels of vWF were measured in 79 patients with UICC Stage I-IV CRC at time of operation and correlated with TNM categories, levels of the carcinoembryonic antigen (CEA), blood groups (BG) and 19 controls (CO). CO included cancer-free patients without bacterial or viral infections. For tissue analysis paraffin embedded tumour and mucosa sections of operation specimens were stained immunohistochemically for vWF and compared to vWF plasma levels as well as to TNM categories.

RESULTS

VWF plasma levels in CRC patients were significantly dependent on blood groups (p=0.012) and elevated compared to the normal ranges as well as to controls (BG 0: p=0.668, BG A/AB/B: p=0.020). CRC-Patients over 60 years of age presented with significantly higher vWF levels than patients below 60 years (BG 0: p=0.005; BG A/AB/B: p=0.035). There was no correlation of vWF plasma levels and UICC stages in CRC. Patients with elevated vWF plasma levels also presented with elevated CEA levels, but significance was missing (p=0.080). VWF concentration within the tumour tissue was independent of concentration within normal mucosa, blood groups, histopathological characteristics and did not correlate with plasma vWF levels.

CONCLUSION

VWF plasma levels are elevated in CRC patients, but not in a stage dependent manner. Besides the tumour at least blood groups and age mainly influence plasma vWF levels. In our opinion vWF as a routinely used clinical marker in CRC cannot be recommended.

A genotype-directed phase I-IV dose-finding study of irinotecan in combination with fluorouracil/leucovorin as first-line treatment in advanced colorectal cancer

Background:

Infusional fluorouracil/leucovorin (FU/LV) plus irinotecan (FOLFIRI) is one of the standard first-line options for patients with metastatic colorectal cancer (mCRC). Irinotecan is converted into 7-ethyl-10-hydroxycamptothecin (SN-38) by a carboxylsterase and metabolised through uridine diphosphate glucuronosyl transferase (UGT1A1). The UGT1A1^*28 allele has been associated with the risk of developing severe toxicities. The present trial was designed to define the maximum tolerated dose according to UGT1A1 genotype. This report focuses on the results of tolerance to different escalated doses of FOLFIRI first-line of chemotherapy.

Patients and methods:

Patients undergoing first-line treatment for mCRC and eligible for treatment with FOLFIRI were classified according to UGT1A1 genotype. A total of 94 patients were eligible for dose escalation of irinotecan. The starting dose of biweekly irinotecan was 180 mg m⁻² for the ^*1/^*1, 110 mg m⁻² for the ^*1/^*28 and 90 mg m⁻² for the ^*28/^*28 genotypes.

Results:

The dose of irinotecan was escalated to 450 mg m⁻² in patients with the ^*1/^*1 genotype, to 390 mg m⁻² in those with the ^*1/^*28 genotype and to 150 mg m⁻² in those with the ^*28/^*28 genotype. Neutropenia and diarrhoea were the most common grade 3 or 4 toxicities.

Conclusions:

Our results demonstrated that the recommended dose of 180 mg m⁻² for irinotecan in FOLFIRI is considerably lower than the dose that can be tolerated for patients with the UGT1A1 ^*1/^*1 and ^*1/^*28 genotypes. The maximum tolerable dose (MTD) in patients with a high-risk UGT1A1 ^*28/^*28 genotype is 30% lower than the standard dose of 180 mg m⁻².

Pharmacogenetic study in rectal cancer patients treated with preoperative chemoradiotherapy: polymorphisms in thymidylate synthase, epidermal growth factor receptor, GSTP1, and DNA repair genes

PURPOSE

Several studies have been performed to evaluate the usefulness of neoadjuvant treatment using oxaliplatin and fluoropyrimidines for locally advanced rectal cancer. However, preoperative biomarkers of outcome are lacking. We studied the polymorphisms in thymidylate synthase, epidermal growth factor receptor, glutathione S-transferase pi 1 (GSTP1), and several DNA repair genes to evaluate their usefulness as pharmacogenetic markers in a cohort of 128 rectal cancer patients treated with preoperative chemoradiotherapy.

METHODS AND MATERIALS

Blood samples were obtained from 128 patients with Stage II-III rectal cancer. DNA was extracted from the peripheral blood nucleated cells, and the genotypes were analyzed by polymerase chain reaction amplification and automated sequencing techniques or using a 48.48 dynamic array on the BioMark system. The germline polymorphisms studied were thymidylate synthase, (VNTR/5'UTR, 2R G>C single nucleotide polymorphism [SNP], 3R G>C SNP), epidermal growth factor receptor (Arg497Lys), GSTP1 (Ile105val), excision repair cross-complementing 1 (Asn118Asn, 8092C>A, 19716G>C), X-ray repair cross-complementing group 1 (XRCC1) (Arg194Trp, Arg280His, Arg399Gln), and xeroderma pigmentosum group D (Lys751Gln). The pathologic response, pathologic regression, progression-free survival, and overall survival were evaluated according to each genotype.

RESULTS

The ∗3/∗3 thymidylate synthase genotype was associated with a greater response rate (pathologic complete remission and microfoci residual tumor, 59% in ∗3/∗3 vs. 35% in ∗2/∗2 and ∗2/∗3; p=.013). For the thymidylate synthase genotype, the median progression-free survival was 103 months for the ∗3/∗3 patients and 84 months for the ∗2/∗2 and ∗2/∗3 patients (p=.039). For XRCC1 Arg399Gln SNP, the median progression-free survival was 101 months for the G/G, 78 months for the G/A, and 31 months for the A/A patients (p=.048).

CONCLUSIONS

The thymidylate synthase genotype and XRCC1 Arg399Gln polymorphism might help to identify Stage II-III rectal cancer patients with a better outcome after preoperative concomitant chemoradiotherapy.

A water soluble prodrug of a novel camptothecin analog is efficacious against breast cancer resistance protein-expressing tumor xenografts

PURPOSE

Identification of a novel topoisomerase I inhibitor which shows superior efficacy and less individual variation than irinotecan hydrochloride (CPT-11).

METHODS

A novel camptothecin analog that is effective against breast cancer resistance protein (BCRP)-positive cells was screened, and a water soluble prodrug was generated. Antitumor activity of the prodrug was examined in BCRP-positive and -negative xenografts both as a single agent and in combination with other anti-cancer drugs.

RESULTS

A novel camptothecin analog, CH0793076, was discovered. Because CH0793076 was found to be highly lipophilic, a water soluble prodrug (TP300) was generated. TP300 is stable in an acidic solution but is rapidly converted to CH0793076 under physiological pH conditions such as in sera. This efficient prodrug activation would minimize interpatient differences in pharmacokinetic and toxicity profiles. Unlike CPT-11, TP300 does not exhibit cholinergic interaction or cause acute diarrhea at effective doses. In mouse xenograft models, TP300 showed antitumor activity against both BCRP-positive and -negative xenografts, whereas CPT-11 was less active against BCRP-positive xenografts. In addition, the effective dose range (MTD/ED(50)) for TP300 was wider than for CPT-11 and TP300 showed additive or synergistic antitumor effects in combination with other anti-cancer drugs such as capecitabine, oxaliplatin, cisplatin, bevacizumab and cetuximab.

CONCLUSION

It is therefore expected that TP300 will provide an additional treatment option for patients who will undergo chemotherapy with camptothecins.

In vitro drug responses in primary and metastatic colorectal cancers

OBJECTIVE

Treatment of primary and metastatic colorectal carcinoma (CRC) based on 5-fluorouracil and folinic acid (5FU + FA), combined with irinotecan (FOLFIRI) or oxaliplatin (FOLFOX), provides response rates approaching 50% and a 20-month overall survival. Approximately 50% of CRC patients fail to respond to one or more drugs in either regimen, in many cases due to inherent or acquired drug resistance. We therefore characterized in vitro drug response and cross-resistance in primary and metastatic CRC lesions.

MATERIALS AND METHODS

The in vitro Extreme Drug Resistance Assay (EDRA) identifies extreme drug resistance (EDR) in solid tumors with over 99% accuracy and appears to mimic the clinical experience. We analyzed EDRA results from 4854 freshly resected CRC biopsies, including 1740 primary and 847 liver metastases.

RESULTS

Primary and metastatic CRCs responded similarly to single agents 5FU + FA, irinotecan, and oxaliplatin. Primary and metastatic tumors expressing EDR to 5FU + FA demonstrated up to 58% cross-resistance to a variety of chemotherapy agents, with the lowest percentages for oxaliplatin (11% and 8%, respectively) and irinotecan (16% and 14%). Importantly, approximately 20% of tumors showed EDR to either FULFOX or FOLFIRI.

CONCLUSION

Overall data analyses indicated that EDRA results obtained at initial diagnosis may be useful in guiding therapy selection for metastatic disease. Pre-testing of tumors before treatment may provide essential drug cross-resistance information for better chemotherapy selection. Prospective clinical trials employing the EDRA are needed to substantiate these data.

Isolation of endothelial cells from human tumors

Antiangiogenic drugs have been used successfully for the treatment of colorectal cancer (CRC) and several other tumor types. Until recently, viable tumor endothelial cells (TEC) and normal endothelial cells of uninvolved colon tissue (NEC) from the same patient have not been available to optimize treatment strategies in vitro. Here, we describe a protocol for the isolation of TEC and NEC. These cells were isolated at a very high purity via magnetic cell sorting of tissue samples obtained from surgical specimens of patients suffering from CRC. Isolated TEC and NEC expressed CD31, CD105, VE-cadherin, VCAM-1, ICAM-1, and E-selectin, formed capillaries in basal membrane extract, and were able to take up acetylated LDL. They were negative for podoplanin, CD45, CD68, and CK-20, indicating blood vessel endothelial lineage. Expression of vWF was more pronounced in NEC cultures, whereas vWF was absent or only slightly expressed in all TEC cultures in vitro. Lower intracellular concentrations of vWF were also detected in TEC as compared to NEC at the tissue level. The latter finding demonstrated that differential features of TEC and NEC in vivo are stably perpetuated in culture. The isolated endothelial cell cultures may provide a useful in vitro model system to elucidate epigenetic effects on angiogenesis in cancer and to optimize antiangiogenic therapy.

Phase I/II study of oncolytic herpes simplex virus NV1020 in patients with extensively pretreated refractory colorectal cancer metastatic to the liver

This multicenter phase I/II study evaluated the safety, pharmacokinetics, and antitumor effects of repeated doses of NV1020, a genetically engineered oncolytic herpes simplex virus, in patients with advanced metastatic colorectal cancer (mCRC). Patients with liver-dominant mCRC received four fixed NV1020 doses via weekly hepatic artery infusion, followed by two or more cycles of conventional chemotherapy. Phase I included cohorts receiving 3 × 10(6), 1 × 10(7), 3 × 10(7), and 1 × 10(8) plaque-forming units (PFU)/dose to determine the optimal biological dose (OBD) for phase II. Blind independent computed tomography scan review was based on RECIST (response evaluation criteria in solid tumors) to assess hepatic tumor response. Phase I and II enrolled 13 and 19 patients, respectively. Patients experienced transient mild-moderate febrile reactions after each NV1020 infusion. Grade 3/4 virus-related toxicity was limited to transient lymphopenia in two patients. NV1020 shedding was not detected. Simultaneous cytokine and grade 1 coagulation perturbations were dose-limiting at 1 × 10(8) PFU/dose, considered the OBD. All 22 OBD patients had previously received 5-fluorouracil; most had received oxaliplatin or irinotecan (50% had both), many with at least one targeted agent. After NV1020 administration, 50% showed stable disease. The best overall tumor control rate after chemotherapy was 68% (1 partial response, 14 stable disease); this did not correlate with baseline variables or chemotherapy. Median time to progression was 6.4 months (95% confidence interval: 2, 8.9); median overall survival was 11.8 months (95% confidence interval: 8.3, 20.7). One-year survival was 47.2%. We conclude that NV1020 stabilizes liver metastases with minimal toxicity in mCRC. It may resensitize metastases to salvage chemotherapy and extend overall survival. A randomized phase II/III trial now appears justified.

Clinical and economic evaluation of first-line therapy with FOLFIRI or modified FOLFOX6 for metastatic colorectal cancer

OBJECTIVE

Recently, significant progress in treatment of metastatic colorectal cancer has been achieved. Either FOLFIRI (fluorouracil, leucovorin and irinotecan) or modified FOLFOX6 (fluorouracil, leucovorin and oxaliplatin, oxaliplatin dose 85 mg/m(2)) is selected as first-line therapy in clinical practice in Japan. However, economic burden of colorectal cancer is considerable.

METHODS

Analysis was made for all patients who were treated with FOLFIRI or modified FOLFOX6 for metastatic colorectal cancer. Regimen of FOLFIRI was compared with modified FOLFOX6 under consideration from clinical and economic standpoints. Progression free survival, response, toxicity and cancer care cost in patients with metastatic colorectal cancer was analyzed. Direct costs based on the fee schedule of the Japanese national health insurance were calculated.

RESULTS

Median progression free survival was 7.7 months for FOLFIRI versus 8.4 months for modified FOLFOX6 (P = 0.48). Overall cost for first four cycles was yen756 284 for FOLFIRI and yen1 081 162 for modified FOLFOX6 (P < 0.0001). All grade alopecia was significantly more frequent with FOLFIRI than with modified FOLFOX6 (P = 0.04). All grade neuropathy was more observed with modified FOLFOX6 than FOLFIRI (P = 0.0002).

CONCLUSIONS

FOLFIRI is inexpensive in the initial stage of treatment which a number of patients can receive chemotherapy than modified FOLFOX6 as first-line therapy for metastatic colorectal cancer in Japanese national insurance system.

Towards biomarker-dependent individualized chemotherapy: exploring cell-specific differences in oxaliplatin-DNA adduct distribution using accelerator mass spectrometry

Oxaliplatin is a third-generation platinum-based anticancer drug that is currently used in the treatment of metastatic colorectal cancer. Oxaliplatin, like other platinum-based anticancer drugs such as cisplatin and carboplatin, is known to induce apoptosis in tumor cells by binding to nuclear DNA, forming monoadducts, and intra- and interstrand diadducts. Previously, we reported an accelerator mass spectrometry (AMS) assay to measure the kinetics of oxaliplatin-induced DNA damage and repair [Hah, S. S.; Sumbad, R. A.; de Vere White, R. W.; Turteltaub, K. W.; Henderson, P. T. Chem. Res. Toxicol.2007, 20, 1745]. Here, we describe another application of AMS to the measurement of oxaliplatin-DNA adduct distribution in cultured platinum-sensitive testicular (833K) and platinum-resistant breast (MDA-MB-231) cancer cells, which resulted in elucidation of cell-dependent differentiation of oxaliplatin-DNA adduct formation, implying that differential adduction and/or accumulation of the drug in cellular DNA may be responsible for the sensitivity of cancer cells to platinum treatment. Ultimately, we hope to use this method to measure the intrinsic platinated DNA adduct repair capacity in cancer patients for use as a biomarker for diagnostics or a predictor of patient outcome.

New insights into the biotransformation and pharmacokinetics of oxaliplatin

Oxaliplatin is used primarily in the treatment of metastatic colorectal cancer. In this minireview, we discuss potentially important biotransformation pathways in light of its short elimination half-life in vivo. We also highlight new information achieved using a selective analytical technique to measure intact oxaliplatin in pharmacokinetic studies (comprising intravenous, intraperitoneal, and intrahepatic administration) and compare to results obtained by measurements of total platinum. The use of selective analytical techniques is strongly recommended giving kinetic parameters of the parent compound and not only to a complex mixture of platinum containing endogenous compounds.

[The development of the first line treatment of metastatic colorectal cancer (mCRC)]

Chemotherapy options of metastatic colorectal cancer (mCRC) have been progressed rapidly in the last years. Besides of the standard fluorouracil/folinic acid treatment some new active agents (oxaliplatin and irinotecan) have been introduced, and more recently the "targeted" biologicals (bevacizumab, cetuximab, panitumumab) have demonstrated their high effectiveness. This review summarizes the development of the first line treatment of mCRC.

Treatments and outcomes of peritoneal surface tumors through a centralized national service (United kingdom)

PURPOSE

Treatment of peritoneal surface malignancies with combined cytoreductive surgery and heated intraperitoneal chemotherapy may improve oncologic outcome. To better define treatment pathways, five-year results in patients referred to one of two centralized national treatment centers in the United Kingdom were analyzed.

METHODS

A prospective database of patients referred to the Manchester Peritoneal Tumor Service, established in 2002, was analyzed. Outcomes were evaluated using Kaplan-Meier life tables and Cox models.

RESULTS

Two hundred seventy-eight patients (median age, 56.9 (range, 16-86) years) were considered by a dedicated multidisciplinary team and tracked on seven clinical pathways. Among the 118 surgically treated, the most common diagnosis was pseudomyxoma peritonei (101 patients, 86%). Major complications occurred in 11 patients (9%); there was no 30-day mortality. Where complete cytoreduction was achieved, three-year and five-year tumor-related survival rates were 94% and 86%, respectively. In the Cox model, incompleteness of cytoreduction (P = 0.001) and high-grade tumor (P < 0.0001) were independent prognosticators of poor outcome.

CONCLUSION

The establishment of a national treatment center has allowed refinement of techniques to achieve internationally recognized results. Having achieved low levels of morbidity and mortality in the treatment of mainly pseudomyxoma peritonei of appendiceal origin, the technique of cytoreductive surgery and heated intraperitoneal chemotherapy may be considered for peritoneal carcinomatosis of colorectal origin.

Peritoneal carcinomatosis and liver metastases from colorectal cancer treated with cytoreductive surgery perioperative intraperitoneal chemotherapy and liver resection

BACKGROUND

An aggressive therapy comprising of cytoreductive surgery (CRS) and perioperative intraperitoneal chemotherapy (PIC) and liver resection/ablation is generally not offered to patients with both colorectal peritoneal carcinomatosis (CRPC) and liver metastases (LM) as it no longer represents a loco-regional disease. We review the outcomes of patients who underwent an aggressive treatment with a curative intent for both CRPC and LM as a prelude towards determining the suitability of this treatment.

METHODS

Patients with CRPC were treated with cytoreductive surgery and perioperative intraperitoneal chemotherapy in our institution. Patients with LM underwent additional treatment of liver resection/ablation. The characteristics and survival of patients with isolated CRPC and those with both CRPC and LM were compared.

RESULTS

Fifty-five patients underwent complete cytoreductive surgery for treatment of CRPC, amongst which 16 patients had LM. The overall median survival was 36 months. Fourteen of the 16 patients treated for CRPC and LM underwent synchronous treatment. When patients with CRPC alone or CRPC with LM were compared, patients with CRPC and LM had a lower PCI (p=0.03), received less HIPEC infusion (p<0.001), received less of both HIPEC and EPIC infusion (p=0.007), had a shorter procedural duration (p=0.001) and required less blood transfusion (p=0.02). There was no difference in survival between patients who had CRPC alone or CRPC with LM who underwent aggressive treatment (p=0.77).

CONCLUSIONS

A curative procedure may be offered to selected patients with CRPC and LM, especially in those with a low peritoneal cancer index.

Protein kinase C-beta II (PKC-beta II) expression in patients with colorectal cancer

PURPOSE

Current development of targeted agents for the treatment of colorectal cancer include the clinical evaluation of kinase inhibitors, such as enzastaurin, a serine/threonine kinase inhibitor designed to suppress signaling through Protein Kinase C (PKC) and AKT pathways. Little is known about the expression of PKC-beta in colorectal cancer or the prognostic value in colorectal cancer, which was the focus of the present study.

METHODS

PKC-beta II protein expression was examined in 99 primary colorectal adenocarcinomas and 33 corresponding regional lymph node metastases by immunohistochemistry (IHC). The PKC-beta II immunoreactivity was mutually compared and correlated with survival information of all examined patients.

RESULTS

Immunohistochemical expression of PKC-beta II was detected in 18/99 carcinomas (18.2%). There was no correlation between PKC-beta II staining and traditional clinicopathological parameters. However the median survival was 2.2 years in PKC-beta II expressing tumors compared to 5.4 in PKC-beta II negative tumors (p = 0.25), with a trend for association to poor prognosis.

CONCLUSION

We here describe for the first time the immunohistochemical detection of PKC-beta II in patients with colorectal cancer and show a trend associating with poor survival. The role of PKC-beta II staining in colorectal tumors deserves further evaluation.

[Chemotherapy of elderly patients with colorectal cancer]

Elderly patients will be the largest group of oncology patients in the future. Because of minimal participation of older patients in randomized clinical trials there is a lack of evidence-based data to make correct decisions with regard to chemotherapy and/or targeted therapy in this age group. Elderly patients have similar benefits from systemic therapies as younger counterparts, but many elders have substantial co-morbidities, which may limit the life expectancy and the effectiveness of systemic therapy. Close collaboration between oncologists and geriatrists will help make decisions on the management of elderly patients suffering from cancer.

Chemotherapy for operable and advanced colorectal cancer

The majority of colorectal cancer patients receive chemotherapy either to palliate advanced unresectable disease or to reduce the risk of recurrence after radical surgery. Thanks to the improvements in systemic chemotherapy, in the last 20 years the median survival time for patients with unresectable metastatic disease has indeed progressively increased from less than 6 to almost 24 months and recurrences after radical surgery in patients with early-stage tumors have been halved. Although colorectal cancer incidence increase with aging, there is limited scientific evidence based on prospective clinical trials to guide the management of elderly colorectal cancer patients. In addition, aging is a continuum process making strict cut-off difficult to define and homogeneous subgroups hard to identify. There is significant heterogeneity also as regards comorbidities, overall physical ability, mental health and functional status. Specific guidelines for the medical treatment of elderly colorectal cancer patients are therefore difficult to draw. While fit patients are generally treated with adult protocols and frail individuals rarely receive chemotherapy, managing the intermediate vulnerable patients requires a careful balance between the biological and psycho-social costs of treatment, the aggressiveness of the tumor and its perception by the patient. In this review, the major achievements of chemotherapy in the treatment of colorectal cancer will be described and the available data addressing the extension of these chemotherapy programs to elderly patients will be discussed. Special emphasis will be given to the development of specific treatment strategies depending on the degree of disease aggressiveness. Empirical suggestions to adapt the chemotherapy programs developed for adult fit patients to subjects with various degrees of vulnerability and frailty will also be given along with practical indications for the use of specific chemotherapeutic agents in the presence of some common elderly-related comorbidities.

A multicenter phase II study of the combination of oxaliplatin, irinotecan and capecitabine in the first-line treatment of metastatic colorectal cancer

The triple drug combination consisting of irinotecan, oxaliplatin and 5-fluorouracil (FOLFOXIRI) has demonstrated higher activity and efficacy compared to the doublet FOLFIRI. 5-Fluorouracil could be substituted in FOLFOXIRI regimen by capecitabine, an oral fluoropyrimidine with similar efficacy. Recently, a dose-finding trial has demonstrated the feasibility of the combination of irinotecan, oxaliplatin and capecitabine (XELOXIRI) and established their recommended doses. The aim of this study was to evaluate the activity of XELOXIRI. A total of 36 patients with unresectable metastatic colorectal cancer received irinotecan 165 mg m⁻² and oxaliplatin 85 mg m⁻² on day 1 plus capecitabine 2000 mg m⁻² per day orally in two doses from day 1 to day 7, every 2 weeks. Grade 3–4 toxicities were infrequent, expect for neutropenia and diarrhoea, which were each observed in 30% of patients. Two complete and twenty-two partial responses were obtained, corresponding to an overall response rate of 67% (95% CI 51.4–82%). After a median follow-up of 17.7 months, the median progression-free and overall survival were 10.1 and 17.9 months, respectively.

The substitution of 5-fluorouracil with capecitabine, in combination with irinotecan and oxaliplatin, is feasible and does not impair the activity of the regimen. However, the XELOXIRI combination is associated with a high incidence of diarrhoea and, therefore, should be considered as a not preferable alternative to FOLFOXIRI.

Second-line chemotherapy in advanced and metastatic CRC

BACKGROUND

Chemotherapy is widely used in colorectal cancer that has relapsed or failed to respond to first-line treatment.

OBJECTIVES

To determine the efficacy of second-line chemotherapy for the treatment of advanced colorectal cancer.

SEARCH STRATEGY

We performed electronic searches in the following databases: MEDLINE (via PubMed; 1964-September 2007), EMBASE (via OVID; 1980-September 2007) and The Cochrane Library 2007, Issue 2.

SELECTION CRITERIA

Studies assessing the efficacy of second-line chemotherapy (single or combined treatment with any chemotherapeutic agent, at any dose and number of cycles) in patients with advanced colorectal cancer that progressed, recurred or did not respond to first-line chemotherapy.

DATA COLLECTION AND ANALYSIS

A descriptive analysis of the included trials was performed, due to the huge clinical heterogeneity between them.

MAIN RESULTS

Seven randomized controlled trials (RCTs) were included; one of high quality, five of moderate quality, and one conference abstract. Second-line chemotherapy (irinotecan) showed moderate benefits in overall survival and progression-free survival over Best Supportive Care (BSC) and fluorouracil (5-FU). Fractionated administration has not proven to be more beneficial and is more toxic. Definitive results concerning the benefits and risks of oxaliplatin are pending publication.

AUTHORS' CONCLUSIONS

Second-line chemotherapy is effective in prolonging time to progression and survival in patients with advanced colorectal cancer. Further RCTs are needed to assess the optimal chemotherapy regimen.

Can UGT1A1 genotyping reduce morbidity and mortality in patients with metastatic colorectal cancer treated with irinotecan? An evidence-based review

This evidence-based review addresses the question of whether testing for UGT1A1 mutations in patients with metastatic colorectal cancer treated with irinotecan leads to improvement in outcomes (e.g., irinotecan toxicity, response to treatment, morbidity, and mortality), when compared with no testing. No studies were identified that addressed this question directly. The quality of evidence on the analytic validity of current UGT1A1 genetic testing methods is adequate (scale: convincing, adequate, inadequate), with available data indicating that both analytic sensitivity and specificity for the common genotypes are high. For clinical validity, the quality of evidence is adequate for studies reporting concentration of the active form of irinotecan (SN-38), presence of severe diarrhea, and presence of severe neutropenia stratified by UGT1A1 common genotypes. The strongest association for a clinical endpoint is for severe neutropenia. Patients homozygous for the *28 allele are 3.5 times more likely to develop severe neutropenia compared with individuals with the wild genotype (risk ratio 3.51; 95% confidence interval 2.03-6.07). The proposed clinical utility of UGT1A1 genotyping would be derived from a reduction in drug-related adverse reactions (benefits) while at the same time avoiding declines in tumor response rate and increases in morbidity/mortality (harms). At least three treatment options for reducing this increased risk have been suggested: modification of the irinotecan regime (e.g., reduce initial dose), use of other drugs, and/or pretreatment with colony-stimulating factors. However, we found no prospective studies that examined these options, particularly whether a reduced dose of irinotecan results in a reduced rate of adverse drug events. This is a major gap in knowledge. Although the quality of evidence on clinical utility is inadequate, two of three reviewed studies (and one published since our initial selection of studies for review) found that individuals homozygous for the *28 allele had improved survival. Three reviewed studies found statistically significant higher tumor response rates among individuals homozygous for the *28 allele. We found little or no direct evidence to assess the benefits and harms of modifying irinotecan regimens for patients with colorectal cancer based on their UGT1A1 genotype; however, results of our preliminary modeling of prevalence, acceptance, and effectiveness indicate that reducing the dose would need to be highly effective to have benefits outweigh harms. An alternative is to increase irinotecan dose among wild-type individuals to improve tumor response with minimal increases in adverse drug events. Given the large number of colorectal cancer cases diagnosed each year, a randomized controlled trial of the effects of irinotecan dose modifications in patients with colorectal cancer based on their UGT1A1 genotype is feasible and could clarify the tradeoffs between possible reductions in severe neutropenia and improved tumor response and/or survival in patients with various UGT1A1 genotypes.

Recommendations from the EGAPP Working Group: can UGT1A1 genotyping reduce morbidity and mortality in patients with metastatic colorectal cancer treated with irinotecan?

SUMMARY OF RECOMMENDATIONS

The Evaluation of Genomic Applications in Practice and Prevention (EGAPP) Working Group found that the evidence is currently insufficient to recommend for or against the routine use of UGT1A1 genotyping in patients with metastatic colorectal cancer who are to be treated with irinotecan, with the intent of modifying the dose as a way to avoid adverse drug reactions (severe neutropenia).

RATIONALE

The EGAPP Working Group (EWG) found no intervention trials showing that targeted dosing of irinotecan based on UGT1A1 genotyping could reduce the rates of two specific adverse drug events, severe (Grade 3-4) neutropenia or diarrhea. Observational studies indicate a significant association between UGT1A1 genotypes, particularly *28/*28 and *1/*28, and the occurrence of severe neutropenia. Observational studies also indicate a possible association between severe diarrhea and these UGT1A1 genotypes, but the association is not statistically significant. An additional finding was the suggestion that reducing irinotecan dose may result in patient harms due to diminished effectiveness of treatment in highest risk individuals (*28/*28 homozygotes), and that a higher dose might be warranted among individuals at lower risk of adverse drug events (*1/*1 and *1/*28 genotypes). This review did not consider higher risk patients (e.g., having previous adverse reactions to irinotecan or additional risk factors for neutropenia).

ANALYTIC VALIDITY

The EWG found adequate evidence to conclude that analytic sensitivity and specificity were high for the commonly tested alleles, but evidence was inadequate for rarer alleles.

CLINICAL VALIDITY

The EWG found adequate evidence of a significant association between UGT1A1 genotype and the incidence of severe neutropenia at standard doses of irinotecan. The EWG found adequate evidence of a possible association between genotype and severe diarrhea, but the effect was smaller and not statistically significant. The EWG found adequate evidence of a significantly higher rate of tumor response to standard irinotecan dosing among individuals with the genotype at highest risk of adverse drug events (*28/*28).

CLINICAL UTILITY

The EWG found no evidence to support clinical utility in the proposed clinical scenario. Preliminary modeling suggests that, even if targeted dosing were to be highly effective, it is not clear that benefits (reduced adverse drug events) outweigh harms (unresponsive tumors).

CONTEXTUAL ISSUES

Addressing patient preferences regarding risk of side effects and quality of life, versus aggressive treatment to potentially improve effectiveness, is expected practice. In addition, a recent study reported that risk for neutropenia was lower at lower irinotecan doses. For treatment regimens utilizing lower irinotecan doses, UGT1A1 genotype may not be a useful indicator of risk for adverse drug events. Further rigorous evaluation of UGT1A1 genotyping using current and promising irinotecan treatment protocols is warranted.

Pharmacoepigenomics in colorectal cancer: a step forward in predicting prognosis and treatment response

Despite therapeutic innovations and increasing education on lifestyle to prevent colorectal cancer, it is still one of the most common cancer types, and for men the second cause of cancer-related death. Lately, much attention has been given to identify molecular markers involved in colorectal cancer prognosis and treatment with the aim to develop a more accurate classification system based on (epi)genetic alterations and, in addition, find markers that could potentially enhance management of colorectal cancer by predicting treatment response in advance. Although many genetic markers have been claimed to have prognostic or predictive influence, results are often inconclusive and, with some exception, they are not used in standard practice. Epigenetic alterations have received less attention although they are probably even more interesting as they can potentially be reversed through drug treatment. This review describes the current knowledge on the prognostic and predictive value of epigenetic markers in colorectal cancer.

Characterization of a subpopulation of colon cancer cells with stem cell-like properties

The biology of the normal colonic mucosa suggests that colon cancer originates from normal colon stem cells. CD44 cancer stem cells have been identified in breast and prostate cancer, and we therefore examined whether CD44 similarly identified colon cancer stem cells. Initial assays found CD44(hi) colon tumor cells to have enhanced soft agar colony-forming ability. Subsequently, CD44(hi) cells isolated from 4 primary colon adenocarcinoma xenografts were found to be highly tumorigenic in immune deficient mice. CD44(hi) cells consistently formed tumors with 1,000 cells, and in multiple experiments, as few as 10 and 100 CD44(hi) cells formed tumors in 7/10 and 21/28 mice, respectively. In contrast, CD44(-) colon tumor cells were either nontumorigenic or 10-50-fold less tumorigenic. CD44(hi) cells could be serially passaged up to 4 times in vivo, suggesting self-renewal capacity, and formed tumors that recapitulated the heterogeneity of the original patient tumor. CD44(hi) cells were significantly enriched for nuclear activated beta-catenin, a key element in normal stem/progenitor cells and in early colon tumor progression. Bromodeoxyuridine (BrdU) labeling studies indicated that CD44(hi) cells divide slowly relative to the CD44(-) cells, suggesting their tumorigenicity is not simply due to faster proliferation. Aldehyde dehydrogenase (ALDH) sort further increased the tumorigenicity of CD44(hi) cells from 2/2 patient tumors, but CD133 tumor cells in our hands did not have increased tumorigenicity. Our observations indicate that CD44 is a marker of stem-like cells in colon cancer, and support the use of additional markers to further purify colon cancer stem cells.