Adjuvant chemotherapy for stage II colorectal cancer: the time is right!

Inhibition of PRMT5-mediated regulation of DKK1 sensitizes colorectal cancer cells to chemotherapy

The Dickkopf family proteins (DKKs) are strong Wnt signaling antagonists that play a significant role in colorectal cancer (CRC) development and progression. Recent work has shown that DKKs, mainly DKK1, are associated with the induction of chemoresistance in CRC and that DKK1 expression in cancer cells correlates with that of protein arginine N-methyltransferase 5 (PRMT5). This points to the presence of a regulatory loop between DKK1 and PRMT5. Herein, we addressed the question of whether PRMT5 contributes to DKK1 expression in CRC and hence CRC chemoresistance. Both in silico and in vitro approaches were used to explore the relationship between PRMT5 and different DKK members. Our data demonstrated that DKK1 expression is significantly upregulated in CRC clinical samples, KRAS-mutated CRC in particular and that the levels of DKK1 positively correlate with PRMT5 activation. Chromatin immunoprecipitation (ChIP) data indicated a possible epigenetic role of PRMT5 in regulating DKK1, possibly through the symmetric dimethylation of H3R8. Knockdown of DKK1 or treatment with the PRMT5 inhibitor CMP5 in combination with doxorubicin yielded a synergistic anti-tumor effect in KRAS mutant, but not KRAS wild-type, CRC cells. These findings suggest that PRMT5 regulates DKK1 expression in CRC and that inhibition of PRMT5 modulates DKK1 expression in such a way that reduces CRC cell growth.

Application of Bevacizumab Combined With Chemotherapy in Patients With Colorectal Cancer and Its Effects on Brain-Gut Peptides, Intestinal Flora, and Oxidative Stress

Objective

To investigate the efficacy of bevacizumab combined with chemotherapy in the treatment of colorectal cancer (CRC) and to analyze the effects on brain peptides, intestinal flora, and oxidative stress in CRC patients.

Methods

Eighty two patients with CRC who were admitted to our hospital from March 2018 to June 2021 were selected as the research subjects and divided into the control group (n = 41) and the observation group (n = 41). The control group was treated with XELOX chemotherapy, and the observation group was additionally treated with bevacizumab, which was repeated every 3 weeks for a total of two treatments. The therapeutic effects of the two groups were evaluated after treatment. The brain-gut peptide index, intestinal flora index and oxidative stress index were detected, and the adverse reactions of the two groups were recorded.

Results

In the control group, ER was 36.59% (15/41) and DCR was 73.17% (30/41). In the observation group, ER was 63.41% (26/41) and DCR was 90.24% (37/41). ER and DCR in the observation group were higher than those in the control group (P < 0.05). After treatment, the levels of motilin and gastrin in the observation group were lower than those in the control group, and ghrelin was higher than that in the control group (P < 0.05). After treatment, the levels of Bifidobacterium, Lactobacilli and Enterococcus in the observation group were higher than those in the control group, and the level of Escherichia coli was lower than that in the control group (P < 0.05). After treatment, the SOD level of the observation group was lower than that of the control group, and the MDA level was higher than that of the control group.

Conclusion

Bevacizumab combined with chemotherapy has good efficacy in the treatment of colorectal cancer patients, which can effectively improve the gastrointestinal motility of patients, regulate the intestinal flora of the body, rebuild the microecological balance, effectively reduce the oxidative stress response of patients, and reduce the incidence of adverse reactions.

Doxorubicin inhibits miR-140 expression and upregulates PD-L1 expression in HCT116 cells, opposite to its effects on MDA-MB-231 cells

One of the most challenging problems in colorectal cancer (CRC) is resistance to chemotherapy drugs such as doxorubicin (DOX). The programmed death ligand-1 (PD-L1) is related to chemoresistance and is overexpressed in several human cancer cell types. Here, we investigated the changes in the expression of PD-L1 in DOX-treated CRC and breast cancer (BRC) cells. Also, to address PD-L1 regulation, we assessed expression levels of miR-140 and miR-34a, two microRNAs that can target the 3' UTR region of the gene encoding PD-L1. HCT116 CRC and MDA-MB-231 BRC cells were treated with various doses of DOX in culture and PD-L1 expression was quantified using qRT-PCR, flow cytometry, and western blot analysis. We also evaluated PD-L1 localization in HCT116 cells by immunofluorescence. Next, we assessed expression of miR-140 and miR-34a in DOX-treated HCT116 and MDA-MB-231 cells. Finally, we investigated whether miR-140 targets the 3' UTR of the gene encoding PD-L1 in HCT116 cells using the p2FP-RNAi RNAi reporter vector system. PD-L1 expression in HCT116 cells, while low at baseline, can be induced by treatment with 0.5 µM DOX. MDA-MB-231 baseline PD-L1 expression exceeded HCT116 cell maximal expression and decreased following DOX treatment. We further demonstrated that PD-L1 localizes to the cell surface in DOX-treated HCT116 cells. While miR-140 expression decreased in DOX-treated HCT116 cells, it increased in DOX-treated MDA-MB-231 cells. MiR-34a expression increased in both DOX-treated cell types. Finally, we present evidence for the regulation of PD-L1 by miR-140 in HCT116 cells. PD-L1 expression can increase following treatment with DOX in HCT116 cells but decrease in MDA-MB-231 cells, suggesting a distinct response to DOX in these two different cancer types. Also, a negative correlation between PD-L1 and miR-140 was observed in DOX-treated HCT116 cells, but not in MDA-MB-231 cells.

Systemic miRNA delivery by nontoxic nanoscale coordination polymers limits epithelial-to-mesenchymal transition and suppresses liver metastases of colorectal cancer

Though early detection and treatment of primary tumors has significantly improved in recent years, metastatic disease remains among the most significant challenges in cancer therapy. Cancer cells can disseminate before the primary tumor is detected to form micro or gross metastases, requiring toxic systemic therapies. To prevent and suppress metastases, we have developed a nontoxic, long-circulating nanoscale coordination polymer (NCP) protecting microRNA (miRNA) in circulation and releasing it in tumors. PtIV(en)2 [en = ethylenediamine] containing NCPs (PtEN) can release a nontoxic, kinetically inert PtII(en)2 compound and carbon dioxide which aids the endosomal escape of its miRNA cargo, miR-655-3p. Without the presence of the PtEN core, the miRNA showed cellular uptake but no effect. When transfected into human colorectal HCT116 cells by NCPs, this oligometastatic miRNA limited proliferation and epithelial-to-mesenchymal transition by preventing β-catenin nuclear translocation and tumor cell invasion. Systemic administrations of PtEN/miR-655-3p sustained effective transfection to reduce liver colonization and tumor burden in a xenogenic hepatic metastatic model of HCT116 without any observable toxicity.

Postoperative adjuvant chemotherapy is associated with a lower incidence of colorectal adenomas in patients with previous colorectal cancer

BACKGROUND AND AIMS

The effects of chemotherapeutic agents on the development of colorectal adenomas in patients with previous colorectal cancer (CRC) are not defined. Therefore, we evaluated the potential effect of adjuvant chemotherapy on the incidence of colorectal adenomas in patients with previous CRC.

METHODS

We selected patients with low-risk stage II CRC with or without postoperative 5-fluorouracil-based adjuvant chemotherapy to reduce selection bias. Among 1808 patients with stage II CRC who underwent colonoscopic surveillance after curative resection of CRC between 2006 and 2013, 192 patients were retrospectively enrolled in this study after matching for age and sex. The patients were divided into 96 patients receiving and 96 patients not receiving 5-fluorouracil-based chemotherapy.

RESULTS

Forty patients (41.7%) exhibited colorectal adenomas among 96 patients who received adjuvant chemotherapy, compared with 50 patients (52.1%) with colorectal adenomas among 96 patients who received surgery only. The incidence rate of advanced adenoma was significantly lower in the chemotherapy group than in the nonchemotherapy group (3.1% vs 10.4%, P = .044). After adjustment for clinically relevant factors such as body mass index, aspirin use, metformin use, number of follow-up colonoscopies, and operation type, adjuvant chemotherapy was found to be associated with a decreased incidence of advanced adenoma (odds ratio, .151; 95% confidence interval, .035-.653; P = .011) in patients with stage II CRC.

CONCLUSIONS

The results showed that chemotherapy in patients with CRC may be associated with a lower risk of colorectal advanced adenoma development.

Doxorubicin-loaded oligonucleotide conjugated gold nanoparticles: A promising in vivo drug delivery system for colorectal cancer therapy

In this study, we propose doxorubicin (DOX) loaded oligonucleotides (ONTs) attached to gold nanoparticles (AuNPs) as a drug delivery system for cancer chemotherapy. DOX is one of the representative cancer chemotherapy agents and is widely used by many researchers as a chemotherapy agent in the drug delivery system. Due to the advantages of AuNPs such as simple steps in synthesis, high surface-area-to-volume ratio, and biocompatibility, we utilized AuNPs as drug delivery vehicle. AuNPs were synthesized by chemical reduction to be 13 nm diameter. The G-C rich oligonucleotides were used both for drug loading sites and AuNPs capping agents. 80% of DOX in solution could be bound to ONTs on AuNPs to became DOX-loaded AuNPs coated with ONTs (Doxorubicin-Oligomer-AuNP, DOA), and about 28% of loaded DOX was released from the as-prepared DOA. Confocal microscopy observation showed that DOA was well transported into cells, and finally the DOX was released into the cell nucleus. The drug's efficacies such as in vitro cytotoxicity and in vivo tumor growth inhibition were demonstrated with SW480 colon cancer cell line and a xenograft mouse model. MTT assay was performed to see the cytotoxicity effect on SW480 cells treated with DOA for 24 h, and the cell viability was determined to be 41.77% (p < 0.001). When DOA was administered regularly to a tumor bearing mouse, the tumor growth inhibition degree was examined by measuring the tumor size. The treatment-control (T/C) ratio was found to be 0.69. Thus, our results suggest the use of DOAs as promising drug delivery systems for colorectal cancer therapy.

Aldose reductase inhibitor increases doxorubicin-sensitivity of colon cancer cells and decreases cardiotoxicity

Anthracycline drugs such as doxorubicin (DOX) and daunorubicin remain some of the most active wide-spectrum and cost-effective drugs in cancer therapy. However, colorectal cancer (CRC) cells are inherently resistant to anthracyclines which at higher doses cause cardiotoxicity. Our recent studies indicate that aldose reductase (AR) inhibitors such as fidarestat inhibit CRC growth in vitro and in vivo. Here, we show that treatment of CRC cells with fidarestat increases the efficacy of DOX-induced death in HT-29 and SW480 cells and in nude mice xenografts. AR inhibition also results in higher intracellular accumulation of DOX and decreases the expression of drug transporter proteins MDR1, MRP1, and ABCG2. Further, fidarestat also inhibits DOX-induced increase in troponin-I and various inflammatory markers in the serum and heart and restores cardiac function in mice. These results suggest that fidarestat could be used as adjuvant therapy to enhance DOX sensitivity of CRC cells and to reduce DOX-associated cardiotoxicity.

Subtle hippocampal deformities in breast cancer survivors with reduced episodic memory and self-reported cognitive concerns

Cancer survivors have lingering cognitive problems, however the anatomical basis for these problems has yet to be fully elucidated. Clinical studies as well as animal models of chemotherapy have pinpointed cell and volume loss to the hippocampus, however, few studies have performed shape analysis of the hippocampus on cancer survivors. This study used high-dimensional deformation mapping analysis to test whether localized hippocampal deformation differs in breast cancer survivors who received adjuvant chemotherapy coupled with hormone blockade therapy, and if deformation was related to subjective self-reported concerns and cognitive performance. 3 T MRI images were acquired from 16 pre-menopausal breast cancer survivors and 18 healthy controls without a history of cancer. Breast cancer survivors had undergone chemotherapy within the eighteen months prior to the study, and were receiving estrogen-blockade therapy at the time of the study. Automated high-dimensional deformation mapping was used to compare localized hippocampal deformation differences between groups. Self-reported subjective concerns were assessed using Neuro-QOL Cognitive Function assessment, whereas cognitive performance was evaluated using the NIH Toolbox Cognition Battery. Relative to healthy controls, cancer survivors showed significantly more inward hippocampal deformation, worse self-reported cognitive functioning, and inferior episodic memory test score. This study is the first of its kind to examine the relationship between hippocampal deformity and cognitive impairment in cancer survivors.

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Cancer survivors demonstrated significant inward hippocampal deformation.

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Survivors self-reported worse cognitive functioning.

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Survivors performed worse than controls on a test of episodic memory.

Carcinoma microsatellite instability status as a predictor of benefit from fluorouracil-based adjuvant chemotherapy for stage II rectal cancer

PURPOSE

Rectal cancers with high microsatellite-instable have clinical and pathological features that differentiate them from microsatellite-stable or low- frequency carcinomas, which was studied rarely in stage II rectal cancer, promoting the present investigation of the usefulness of microsatellite-instability status as a predictor of the benefit of adjuvant chemotherapy with fluorouracil in stage II rectal cancer.

PATIENTS AND METHODS

Data of 460 patients who underwent primary anterior resection with a double stapling technique for rectal carcinoma at a single institution from 2008 to 2012 were retrospectively collected. All patients experienced a total mesorectal excision (TME) operation. Survival analysis were analyzed using the Cox regression method.

RESULTS

Five-year rate of disease-free survival (DFS) was noted in 390 (84.8%) of 460 patients with stage II rectal cancer. Of 460 tissue specimens, 97 (21.1%) exhibited high-frequency microsatellite instability. Median age of the patients was 65 (50-71) and 185 (40.2%) were male. After univariate and multivariate analysis, microsatellite instability (p= 0.001), female sex (p< 0.05) and fluorouracil-based adjuvant chemotherapy (p< 0.001), the 3 factors were attributed to a favorable survival status independently. Among 201 patients who did not receive adjuvant chemotherapy, those cancers displaying high-frequency microsatellite instability had a better 5-year rate of DFS than tumors exhibiting microsatellite stability or low-frequency instability (HR, 13.61 [95% CI, 1.88 to 99.28]; p= 0.010), while in 259 patients who received adjuvant chemotherapy, there was no DFS difference between the two groups (p= 0.145). Furthermore, patients exhibiting microsatellite stability or low-frequency instability who received adjuvant chemotherapy had a better 5-year rate of DFS than patients did not (HR, 5.16 [95% CI, 2.90 to 9.18]; p< 0.001), while patients exhibiting high-frequency microsatellite instability were not connected with increased DFS (p= 0.696). It was implied that female patients had better survival than male.

CONCLUSION

Survival status after anterior resection of rectal carcinoma is related to the microsatellite instability status, adjuvant chemotherapy and gender. Fluorouracil-based adjuvant chemotherapy benefits patients of stage II rectal cancer with microsatellite-stable or low microsatellite-instable, but not those with high microsatellite- instable. Additionally, free of adjuvant chemotherapy, carcinomas with high microsatellite-instable have a better 5-year rate of DFS than those with microsatellite-stable or low microsatellite-instable, and female patients have a better survival as well.

Comparing the effectiveness of capecitabine versus 5-fluorouracil/leucovorin therapy for elderly Taiwanese stage III colorectal cancer patients based on quality-of-life measures (QLQ-C30 and QLQ-CR38) and a new cost assessment tool

BACKGROUND

Colorectal cancer (CRC) is a leading cause of cancer-related deaths in developed countries and its incidence increases with age. Intravenous administration of bolus 5-fluorouracil (5-FU) and leucovorin (LV) has been a standard treatment regime for stage III CRC. However, patients generally prefer oral therapy such as Capecitabine. Studies showed that combination of oxaliplatin and capecitabine demonstrated efficacy and safety on par with treatment involving various 5-FU/LV-based regimens in elderly patients as they are in younger ones. However, little is known regarding the cost of adjuvant therapy or the effect of therapy on HRQoL. Thus the aims of this study were to evaluate the influence of different adjuvant care for stage III CRC on the HRQoL of elderly patients and to compare the economic costs associated with capecitabine-based and 5-FU/LV-based adjuvant treatments from a societal perspective in Taiwan.

METHODS

A prospective, open-label, observational, multicenter study involving 123 patients aged 70 and over from 11 different centers was conducted between July 2008 and July 2011 in Taiwan. The adjusted monthly costs per patient and HRQoL were evaluated from individual-level data. The HRQoL of patients was assessed before and after adjuvant treatment. Direct and indirect costs of adjuvant treatment were estimated from a number of sources, and QoL scores were compared between groups.

RESULTS

After correcting for baseline characteristics of patients, no significant differences were observed in the global HRQoL scores between treatment groups during the study period. According to QLQ-CR38 results, capecitabine-based therapy appeared to alleviate problems related to defecation (4.54 vs. 8.5; P = 0.011); however, micturition problems increased (9.27 vs. 7.51; P = 0.04), compared with 5-FU/LV-based treatment. The adjusted monthly treatment cost per patient was NT$27,300 for capecitabine-based treatment and NT$53,671 for 5-FU/LV-based treatment. The total cost of 5-FU/LV-based treatment was 59 % greater than that of capecitabine-based treatment.

CONCLUSIONS

Analyzing from the societal perspective in Taiwan, capecitabine-based therapy incurred lower treatment costs than 5-FU/LV-based therapy and did not jeopardize HRQoL. Therefore, capecitabine, with or without oxaliplatin, could be considered as an alternative treatment option for elderly patients with stage III CRC.

Quantification of tumour budding, lymphatic vessel density and invasion through image analysis in colorectal cancer

BACKGROUND

Tumour budding (TB), lymphatic vessel density (LVD) and lymphatic vessel invasion (LVI) have shown promise as prognostic factors in colorectal cancer (CRC) but reproducibility using conventional histopathology is challenging. We demonstrate image analysis methodology to quantify the histopathological features which could permit standardisation across institutes and aid risk stratification of Dukes B patients.

METHODS

Multiplexed immunofluorescence of pan-cytokeratin, D2-40 and DAPI identified epithelium, lymphatic vessels and all nuclei respectively in tissue sections from 50 patients diagnosed with Dukes A (n = 13), Dukes B (n = 29) and Dukes C (n = 8) CRC. An image analysis algorithm was developed and performed, on digitised images of the CRC tissue sections, to quantify TB, LVD, and LVI at the invasive front.

RESULTS

TB (HR =5.7; 95% CI, 2.38-13.8), LVD (HR =5.1; 95% CI, 2.04-12.99) and LVI (HR =9.9; 95% CI, 3.57-27.98) were successfully quantified through image analysis and all were shown to be significantly associated with poor survival, in univariate analyses. LVI (HR =6.08; 95% CI, 1.17-31.41) is an independent prognostic factor within the study and was correlated to both TB (Pearson r =0.71, p <0.0003) and LVD (Pearson r =0.69, p <0.0003).

CONCLUSION

We demonstrate methodology through image analysis which can standardise the quantification of TB, LVD and LVI from a single tissue section while decreasing observer variability. We suggest this technology is capable of stratifying a high risk Dukes B CRC subpopulation and we show the three histopathological features to be of prognostic significance.

Association of ABCB1 genetic polymorphisms with susceptibility to colorectal cancer and therapeutic prognosis

AIM

To evaluate the association of ABCB1 gene polymorphisms with susceptibility to colorectal cancer (CRC) and clinical outcomes of CRC patients with chemotherapy.

PATIENTS & METHODS

A case-control study was performed on the C3435T, C1236T and G2677T/A polymorphisms in the ABCB1 gene in 1028 CRC patients and 1230 controls.

RESULTS

We observed that the ABCB1 C3435T and G2677T/A variants as well as the 3435T-1236T-2677T haplotype significantly increased the risk of CRC. The ABCB1 C3435T CT genotype had a significant effect on the time to recurrence (adjusted hazard ratio [HR; 95% CI]: 0.560 [0.355-0.882]; p = 0.012). Moreover, ABCB1 C1236T variant carriers displayed a longer overall survival after postoperative oxaliplatin-based chemotherapy (adjusted HR [95% CI]: 0.354 [0.182-0.692], 0.646 [0.458-0.910], respectively). In addition, 1236TT-2677TT-3435TT haplotype carriers showed a worse progression-free survival (adjusted HR [95% CI]: 1.477 [1.012-3.802]; p = 0.043) and recurrence-free survival (adjusted HR [95% CI]: 2.183 [1.253-3.802]; p = 0.006).

CONCLUSION

The ABCB1 polymorphisms might be a candidate pharmacogenomic factor to assess susceptibility and prognosis after oxaliplatin-based chemotherapy for CRC patients.

Elevated ALCAM shedding in colorectal cancer correlates with poor patient outcome

Molecular biomarkers of cancer are needed to assist histologic staging in the selection of treatment, outcome risk stratification, and patient prognosis. This is particularly important for patients with early-stage disease. We show that shedding of the extracellular domain of activated leukocyte cell adhesion molecule (ALCAM) is prognostic for outcome in patients with colorectal cancer (CRC). Previous reports on the prognostic value of ALCAM expression in CRC have been contradictory and inconclusive. This study clarifies the prognostic value of ALCAM by visualizing ectodomain shedding using a dual stain that detects both the extracellular and the intracellular domains in formalin-fixed tissue. Using this novel assay, 105 patients with primary CRCs and 12 normal mucosa samples were evaluated. ALCAM shedding, defined as detection of the intracellular domain in the absence of the corresponding extracellular domain, was significantly elevated in patients with CRC and correlated with reduced survival. Conversely, retention of intact ALCAM was associated with improved survival, thereby confirming that ALCAM shedding is associated with poor patient outcome. Importantly, analysis of patients with stage II CRC showed that disease-specific survival is significantly reduced for patients with elevated ALCAM shedding (P = 0.01; HR, 3.0), suggesting that ALCAM shedding can identify patients with early-stage disease at risk of rapid progression.

The Arf/p53 protein module, which induces apoptosis, down-regulates histone H2AX to allow normal cells to survive in the presence of anti-cancer drugs

BACKGROUND

It is unclear how DNA-damaging agents target cancer cells over normal somatic cells.

RESULTS

Arf/p53-dependent down-regulation of H2AX enables normal cells to survive after DNA damage.

CONCLUSION

Transformed cells, which harbor mutations in either Arf or p53, are more sensitive to DNA-damaging agents.

SIGNIFICANCE

Cellular transformation renders cells more susceptible to some DNA-damaging agents. Anti-cancer drugs generally target cancer cells rather than normal somatic cells. However, the factors that determine this differential sensitivity are poorly understood. Here we show that Arf/p53-dependent down-regulation of H2AX induced the selective survival of normal cells after drug treatment, resulting in the preferential targeting of cancer cells. Treatment with camptothecin, a topoisomerase I inhibitor, caused normal cells to down-regulate H2AX and become quiescent, a process mediated by both Arf and p53. In contrast, transformed cells that harbor mutations in either Arf or p53 do not down-regulate H2AX and are more sensitive to drugs unless they have developed drug resistance. Such transformation-associated changes in H2AX expression rendered cancer cells more susceptible to drug-induced damage (by two orders of magnitude). Thus, the expression of H2AX and γH2AX (phosphorylated form of H2AX at Ser-139) is a critical factor that determines drug sensitivity and should be considered when administering chemotherapy.

Cathepsin D Expression in Colorectal Cancer: From Proteomic Discovery through Validation Using Western Blotting, Immunohistochemistry, and Tissue Microarrays

Despite recent advances in surgical techniques and therapeutic treatments, survival from colorectal cancer (CRC) remains disappointing with some 40–50% of newly diagnosed patients ultimately dying of metastatic disease. Current staging by light microscopy alone is not sufficiently predictive of prognosis and would benefit from additional support from biomarkers in order to stratify patients appropriately for adjuvant therapy. We have identified that cathepsin D expression was significantly greater in cells from invasive front (IF) area and liver metastasis (LM) than those from main tumour body (MTB). Cathepsin D expression was subsequently examined by immunohistochemistry in tissue microarrays from 119 patients with CRC. Strong expression in tumour cells at the IF did not correlate significantly with any clinico-pathological parameters examined or patient survival. However, cathepsin D expression in cells from the MTB was highly elevated in late stage CRC and showed significant correlation with subsequent distant metastasis and shorter cancer-specific survival. We also found that macrophages surrounding tumour cells stained strongly for cathepsin D but there was no significant correlation found between cathepsin D in macrophages at IF and MTB of CRC patient with the clinic-pathological parameters examined.

Development and progression of colorectal neoplasia

A variety of genetic and molecular alterations underlie the development and progression of colorectal neoplasia (CRN). Most of these cancers arise sporadically due to multiple somatic mutations and genetic instability. Genetic instability includes chromosomal instability (CIN) and microsatellite instability (MSI), which is observed in most hereditary non-polyposis colon cancers (HNPCCs) and accounts for a small proportion of sporadic CRN. Although many biomarkers have been used in the diagnosis and prediction of the clinical outcomes of CRNs, no single marker has established value. New markers and genes associated with the development and progression of CRNs are being discovered at an accelerated rate. CRN is a heterogeneous disease, especially with respect to the anatomic location of the tumor, race/ethnicity differences, and genetic and dietary interactions that influence its development and progression and act as confounders. Hence, efforts related to biomarker discovery should focus on identification of individual differences based on tumor stage, tumor anatomic location, and race/ethnicity; on the discovery of molecules (genes, mRNA transcripts, and proteins) relevant to these differences; and on development of therapeutic approaches to target these molecules in developing personalized medicine. Such strategies have the potential of reducing the personal and socio-economic burden of CRNs. Here, we systematically review molecular and other pathologic features as they relate to the development, early detection, diagnosis, prognosis, progression, and prevention of CRNs, especially colorectal cancers (CRCs).

Topoisomerase I but not thymidylate synthase is associated with improved outcome in patients with resected colorectal cancer treated with irinotecan containing adjuvant chemotherapy

Background

Thymidylate synthase (TS) and Topoisomerase I (Topo I) are significant biomarkers in colorectal cancer (CRC). We aimed to study the expression of TS and Topo I in patients with resected CRC who received adjuvant chemotherapy and correlated it with clinical outcome.

Methods

All patients diagnosed with CRC between 1989 and 2007 and treated with adjuvant chemotherapy within Hellenic Cooperative Oncology Group's (HeCOG) protocols, were identified. Archival paraffin-embedded tumor tissues were used for immunohistochemical detection of TS and Topo I. Immunohistochemistry was performed on tissue microarray slides using monoclonal antibodies against TS and Topo I. The results were correlated with survival (OS) and disease free survival (DFS).

Results

A cohort of 498 patients with a median age of 61 years and Dukes' stage B (49%) and C (51%) fulfilled the criteria of the study. All patients received adjuvant 5-FU-based chemotherapy, 38% irinotecan-containing. Positive TS and Topo I expression was found in 43% and 48% of cases, respectively. Five-year OS was 74% and DFS was 68%. In univariate analysis no association of TS and Topo I expression with OS and DFS was identified. In multivariate analysis however, Topo I expression was associated with a reduced risk of death (HR = 0.61, 95% CI 0.42-0.88, p = 0.009). In the irinotecan-treated subgroup, those patients who expressed Topo I had a better OS (HR = 0.47, 95% CI 0.23-0.94, p = 0.033).

Conclusion

Patients with resected CRC expressing Topo I seem to benefit from irinotecan-containing adjuvant chemotherapy. However randomised prospective trials are needed to confirm these results.

Adjuvant therapy for completely resected stage II colon cancer

BACKGROUND

Colon cancer is potentially curable by surgery. Although adjuvant chemotherapy benefits patients with stage III disease, there is uncertainty of such benefit in stage II colon cancer. A systematic review of the literature was performed to better define the potential benefits of adjuvant therapy for patients with stage II colon cancer.

OBJECTIVES

To determine the effects of adjuvant therapy on overall survival and disease-free survival in patients with stage II colon cancer.

SEARCH STRATEGY

Ovid MEDLINE (1986-2007), EMBASE (1980-2007), and EBM Reviews - Cochrane Central Register of Controlled Trials ( to 2007) were searched using the medical headings "colonic neoplasms", "colorectal neoplasms", "adjuvant chemotherapy", "adjuvant radiotherapy" and "immunotherapy", and the text words "colon cancer" and "colonic neoplasms". In addition, proceedings from the annual meetings of the American Society of Clinical Oncology and the European Society of Medical Oncology (1996 to 2004) as well as personal files were searched for additional information.

SELECTION CRITERIA

Randomized trials or meta-analyses containing data on stage II colon cancer patients undergoing adjuvant therapy versus surgery alone.

DATA COLLECTION AND ANALYSIS

:Three reviewers summarized the results of selected studies. The main outcomes of interest were overall and disease-free survival, however, data on toxicity and treatment delivery were also recorded.

MAIN RESULTS

With regards to the effect of adjuvant therapy on stage II colon cancer, the pooled relative risk ratio for overall survival was 0.96 (95% confidence interval 0.88, 1.05). With regards to disease-free survival, the pooled relative risk ratio was 0.83 (95% confidence interval 0.75, 0.92).

AUTHORS' CONCLUSIONS

Although there was no improvement in overall survival in the pooled analysis, we did find that disease-free survival in patients with stage II colon cancer was significantly better with the use of adjuvant therapy. It seems reasonable to discuss the benefits of adjuvant systemic chemotherapy with those stage II patients who have high risk features, including obstruction, perforation, inadequate lymph node sampling or T4 disease. The co-morbidities and likelihood of tolerating adjuvant systemic chemotherapy should be considered as well. There exists a need to further define which high-risk features in stage II colon cancer patients should be used to select patients for adjuvant therapy. Also, researchers must continue to search for other therapies which might be more effective, shorter in duration and less toxic than those available today.

African-American and Caucasian disparities in colorectal cancer mortality and survival by data source: an epidemiologic review

Over the past four decades in the United States, there has been a divergent trend in mortality rates between African-Americans and Caucasians with colorectal cancer (CRC). Rates among Caucasians have been steadily declining, whereas rates among African-Americans have only started a gradual decline in recent years. We reviewed epidemiologic studies of CRC racial disparities between African-Americans and Caucasians, including studies from SEER and population-based cancer registries, Veterans Affairs (VA) databases, healthcare coverage databases, and university and other medical center data sources. Elevated overall and stage-specific risks of CRC mortality and shorter survival for African-Americans compared with Caucasians were reported across all data sources. The magnitude of racial disparities varied across study groups, with the strongest associations observed in university and non-VA hospital-based medical center studies, while an attenuated discrepancy was found in VA database studies. An advanced stage of disease at the time of diagnosis among African-Americans is a major contributing factor to the racial disparity in survival. Several studies, however, have shown that an increased risk of CRC death among African-Americans remains even after controlling for tumor stage at diagnosis, socioeconomic factors, and co-morbidity. Despite advances in treatment, improvements in the standard of care, and increased screening options, racial differences persist in CRC mortality and survival. Therefore, continued research efforts are necessary to disentangle the clinical, social, biological, and environmental factors that constitute the racial disparity. In addition, results across data sources should be considered when evaluating racial differences in cancer outcomes.

Prognostic significance of thymidylate synthase, dihydropyrimidine dehydrogenase and thymidine phosphorylase protein expression in colorectal cancer patients treated with or without 5-fluorouracil-based chemotherapy

BACKGROUND

Low tumour expression levels of thymidylate synthase (TS), dihydropyrimidine dehydrogenase (DPD) and thymidine phosphorylase (TP) have been linked with improved outcome for colorectal cancer (CRC) patients treated with 5-fluorouracil (5-FU). It is unclear whether this occurs because such tumours have better prognosis or they are more sensitive to 5-FU treatment.

PATIENTS AND METHODS

Associations between TS, DPD and TP levels, determined by tissue microarrays and immunohistochemistry, and survival was evaluated in 945 CRC patients according to treatment status.

RESULTS

Low TS and DPD expression associated with worse prognosis in stage II [hazard ratio (HR) = 1.69, 95% confidence interval (CI) (1.09-2.63) and HR = 1.92 (95% CI 1.23-2.94), respectively] and stage III CRC patients treated by surgery alone [HR = 1.39 (95% CI 0.92-2.13) and HR = 1.49 (95% CI 1.02-2.17), respectively]. Low TS, DPD and TP associated with trends for better outcome in stage III patients treated with 5-FU [HR = 0.81 (95% CI 0.49-1.33), HR = 0.70 (95% CI 0.42-1.15) and HR = 0.66 (95% CI 0.39-1.12), respectively].

CONCLUSION

Low TS and DPD expression are prognostic for worse outcome in CRC patients treated by surgery alone, whereas low TS, DPD and TP expression are prognostic for better outcome in patients treated with 5-FU chemotherapy. These results provide indirect evidence that low TS, DPD and TP protein expression are predictive of good response to 5-FU chemotherapy.

Chemotherapy for colorectal cancer prior to liver resection for colorectal cancer hepatic metastases does not adversely affect peri-operative outcomes

BACKGROUND

Systemic chemotherapy is being used increasingly in patients with colorectal cancer. The effects of prior systemic adjuvant or palliative chemotherapy on morbidity following hepatic resection for metastases are not well defined.

OBJECTIVES

To assess the peri-operative impact of systemic chemotherapy on liver resection for colorectal cancer hepatic metastases.

METHODS

Ninety-six resections for colorectal cancer hepatic metastases performed from July 2001 to July 2003 (93% > or =2 segments) were reviewed. Pre-operative demographics, peri-operative features, and post-operative outcomes were collected prospectively. Type of chemotherapy and the temporal relationship of chemotherapy to the liver resection were analyzed.

RESULTS

Fifty-three of 96 patients (55%) received a mean of 5.7 cycles (6.1 months) of systemic chemotherapy prior to hepatic resection, with a median interval of 12 months from end of chemotherapy to liver resection (range 1-75 months). Thirty-five received 5-fluorouracil/leucovorin (5-FU/LV) alone, nine had irinotecan (CPT-11) in addition to 5-FU/LV, and nine were not specified. Pre-operative age, sex, co-morbidities, ASA score, biochemical and liver enzyme profiles, tumor number, and extent and technique of hepatic resection were the same in the chemotherapy and non-chemotherapy cohorts. Mean tumor size was smaller (4.5 cm vs. 5.8 cm) and synchronous metastases were half as common (25% vs. 49%) in the chemotherapy group. Liver resection operative time was equivalent (270 min) in the two groups. Higher estimated blood loss (EBL) (1,000 ml vs. 850 ml), but fewer transfusions (23% vs. 15%) were associated with the chemotherapy group. Although not statistically significant, post-operative liver enzyme peaks were higher in the chemotherapy group (AST = 402 U/L vs. 302 U/L, P = 0.09 and ALT = 433 U/L vs. 312 U/L, P = 0.1). Peak changes in INR and serum bilirubin did not differ. Complications and length of stay (LOS) did not differ between the groups. The only post-operative death was in the non-chemotherapy group. Interestingly, hepatic steatosis was present in 28% of the non-chemotherapy cases and 57% of the chemotherapy resection specimens (P = 0.005) and was marked (>30%) in 7% and 10%, respectively. Further analysis of the chemotherapy group based on the interval between completion of chemotherapy and the hepatic resection (<6 months, 7-12 months, 1-2 years, and >2 years) revealed a trend towards worse outcomes in most categories for those in the >2 years cohort. When comparing the 5-FU/LV alone, to the CPT-11 group there were no significant differences except higher intra-operative blood loss in the group receiving 5-FU/LV alone (1,295 ml vs. 756 ml, P = 0.01).

CONCLUSION

Despite variations in biochemical function and hepatic steatosis, short-term clinical outcomes are not affected by the administration of chemotherapy prior to hepatic resection. Furthermore, there is no detrimental effect of close timing of chemotherapy prior to resection, and there are no appreciable differences between irinotecan containing regimes and more traditional 5-FU-only based therapies, although the subset sample sizes were small in this study.

A Complication-Free Course Ensures a Survival Advantage in Patients after Regional Therapy for Metastatic Colorectal Cancer

Hepatic artery infusional (HAI) chemotherapy has been shown to favorably impact outcome in patients with metastatic colorectal cancer, but complications often preclude complete treatment. The purpose of this study was to determine whether HAI complications impact survival in these patients. Patients undergoing HAI pump placement at our institution from September 2001 to July 2004 were separated into terciles based on the number of treatments completed: ≤1 (none), 2 to 4 (partial), and ≥5 (complete). Complications relating to pump placement or treatment were recorded for each and their impact on survival was determined. Kaplan-Meier survival in 15 patients receiving no treatment was significantly shorter than 7 patients completing therapy (P = 0.02). Thirty-three per cent of patients receiving no therapy were alive at 26 months, whereas 63 per cent of partially and 86 per cent of completely treated patients were alive at 32 and 30 months, respectively. Patients receiving no treatment had more overall complications (80%) and significantly (P < 0.05) more pump-related complications (60%) than those completing therapy (43% and 0%, respectively). Cox regression revealed a significant correlation to gender (hazard ratio, 3.9), tumor size (hazard ratio, 1.17), and carcinoembryonic antigen level (hazard ratio, 1.02) to survival. Patients receiving complete HAI treatment survive longer than those receiving no treatment. Potentially preventable pump-related complications not only impacted the patients’ ability to continue therapy, but survival times as well.

Real-time reverse transcription PCR and the detection of occult disease in colorectal cancer

Molecular diagnostics offers the promise of accurately matching patient with treatment, and a resultant significant effect on improved disease outcome. More specifically, the real-time reverse transcription polymerase chain reaction (qRT-PCR), with its combination of conceptual simplicity and technical utility, has the potential to become a valuable analytical tool for the detection of mRNA targets from tissue biopsies and body fluids. Its potential is particularly promising in cancer patients, both as a prognostic assay and for monitoring response to therapy. Colorectal cancer provides an instructive paradigm for this potential as well as the problems associated with its use as a clinical assay. Currently, histopathological staging, which provides a static description of the anatomical extent of tumour spread within a surgical specimen, defines patient prognosis. The detection of lymph node (LN) metastasis constitutes the most important prognostic factor in colorectal cancer and as the primary indicator of systemic disease spread, LN status determines the choice of postoperative adjuvant chemotherapy. However, its limitations are emphasised by the considerable prognostic heterogeneity of patients within a given tumour stage: not all patients with LN-negative cancers are cured and not all patients with LN-positive tumours die from their disease. This has resulted in a search for more accurate staging protocols and has seen the introduction of the concept of "molecular staging", the incorporation of molecular parameters into clinical tumour staging. Quantification of disease-associated mRNA is one such parameter that utilises the qRT-PCR assay's potential for generating quantitative results. These are not only more informative than qualitative data, but contribute to assay standardisation and quality management. This review provides an assessment of the practical value to the clinician of RT-PCR-based molecular diagnostics. It points out reasons for the many contradictory results encountered in the literature and concludes that there is an urgent need for standardisation at every level, starting with pre-assay sample acquisition and template preparation, assay protocols and post-assay analysis.