CD133 expression predicts for non-response to chemotherapy in colorectal cancer

The cancer stem cell hypothesis may explain why conventional chemotherapies are unable to fully eradicate cancers. In this study, we examined both the prognostic and predictive significance of putative cancer stem cell markers in colorectal cancer. In this study, immunohistochemistry for three candidate cancer stem cell markers (CD133, Oct-4 and Sox-2) and for six other postulated prognostic markers (CK7, CK20, Cox-2, Ki-67, p27 and p53) were performed using tissue microarrays containing 501 primary colorectal cancer cases. Receiver-operating characteristic analysis was used to determine cut-off scores for positive protein expression. Multivariate analysis revealed that positive expression for CD133 and Oct-4 was associated with significantly worse survival in patients treated by surgery alone (P=0.023 and P

The expression of RUNX3 in colorectal cancer is associated with disease stage and patient outcome

RUNX3 is believed to have tumour suppressor properties in several cancer types. Inactivation of RUNX3 has been shown to occur by methylation-induced transcriptional silencing and by mislocalization of the protein to the cytoplasm. The aim of this study was to examine the clinical significance of RUNX3 expression in a large series of colorectal cancers using immunohistochemistry and tissue arrays. With advancing tumour stage, expression of RUNX3 in the nucleus decreased, whereas expression restricted to the cytoplasmic compartment increased. Nuclear RUNX3 expression was associated with significantly better patient survival compared to tumours in which the expression of RUNX3 was restricted to the cytoplasm (P = 0.025). These results support a role for RUNX3 as a tumour suppressor in colorectal cancer.

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.

Discordant quantitative detection of putative biomarkers in nodal micrometastases of colorectal cancer: biological and clinical implications

Aims: Nodal expression of the carcinoembryonic antigen ( CEA), cytokeratin 20 ( CK20), and guanylyl cyclase C ( GCC) genes was measured in tandem in patients with colorectal cancer ( CRC) to assess whether there would be sufficient agreement between these markers in their ability to detect micrometastasis to qualify one of them as a universal marker, and whether frozen and paraffin wax embedded tissues would yield similar results.

Clinical and molecular characteristics of hereditary non-polyposis colorectal cancer families in Southeast Asia

Hereditary non-polyposis colorectal cancer (HNPCC), predominantly due to germline MLH1/MSH2 mutations, is the commonest form of hereditary colorectal cancer (CRC), but data in Asians are sparse. We sequenced the MLH1/MSH2 coding and promoter core regions in CRC patients diagnosed below age 40, and/or with multiple primary cancers or familial cancer clustering suggestive of HNPCC, and correlated deleterious mutations with clinical and tumour features. Forty-six Chinese, Malay and Indian kindreds participated. Of the 153 cancers reported in the 46 kindreds, stomach (14%) and urogenital cancers (13%) were the most common extracolonic cancers, whereas endometrial cancer comprised only 7%. Eleven different MLH1 and 12 MSH2 mutations were identified, including nine novel and four recurring mutations in the Chinese. One Indian was a compound heterozygote for an MLH1 and MSH2 mutation. The MLH1/MSH2 mutation data in the Malays and the Indians represents the first in these ethnic groups. Factors strongly associated with deleterious mutations were the Amsterdam criteria, family history of stomach or multiple primary cancers, and MSI-high tumours, whereas family history of endometrial cancer and young cancer age alone correlated poorly. Distinct clinical and molecular characteristics were identified among Asian HNPCC kindreds and may have important clinical implications.

Intrinsic variability in the detection of micrometastases in lymph nodes for re-staging of colorectal cancer: effect of individual markers and tissue samples

In this study, we investigated whether (a) carcinoembryonic antigen (CEA), cytokeratin-20 (CK-20) and guanylyl cyclase C (GCC) are clinically useful markers for the molecular detection of submicroscopic metastases in colorectal cancer (CRC) and (b) whether overexpression of CEA, CK-20 and GCC can be reliably detected in formalin-fixed, paraffin-embedded tissues as well as frozen lymph nodes. We studied 175 frozen lymph nodes and 158 formalin-fixed, paraffin-embedded lymph nodes from 28 cases of CRC. CEA or CK-20 or GCC-specific polymerase chain reaction (PCR) was carried out on mRNA transcripts extracted from the nodal tissues. Ten out of I I Dukes' B CRC cases had detectable CEA and CK-20 while 6 out of 11 Dukes' B CRC cases had detectable GCC. In general, the difference of re-staged cases when comparing frozen and paraffin-embedded samples was marked; the only statistically significant correlation between frozen and paraffin tissue was for the CEA marker. Our results indicated a high incidence (>50%) of detecting micrometastases in histologically-negative lymph nodes at the molecular level. (C) 2003 Elsevier Science Ltd. All rights reserved.

The Colorectal cancer disease-specific transcriptome may facilitate the discovery of more biologically and clinically relevant information

BACKGROUND: To date, there are no clinically reliable predictive markers of response to the current treatment regimens for advanced colorectal cancer. The aim of the current study was to compare and assess the power of transcriptional profiling using a generic microarray and a disease-specific transcriptome-based microarray. We also examined the biological and clinical relevance of the disease-specific transcriptome.

METHODS: DNA microarray profiling was carried out on isogenic sensitive and 5-FU-resistant HCT116 colorectal cancer cell lines using the Affymetrix HG-U133 Plus2.0 array and the Almac Diagnostics Colorectal cancer disease specific Research tool. In addition, DNA microarray profiling was also carried out on pre-treatment metastatic colorectal cancer biopsies using the colorectal cancer disease specific Research tool. The two microarray platforms were compared based on detection of probesets and biological information.

RESULTS: The results demonstrated that the disease-specific transcriptome-based microarray was able to out-perform the generic genomic-based microarray on a number of levels including detection of transcripts and pathway analysis. In addition, the disease-specific microarray contains a high percentage of antisense transcripts and further analysis demonstrated that a number of these exist in sense:antisense pairs. Comparison between cell line models and metastatic CRC patient biopsies further demonstrated that a number of the identified sense:antisense pairs were also detected in CRC patient biopsies, suggesting potential clinical relevance.

CONCLUSIONS: Analysis from our in vitro and clinical experiments has demonstrated that many transcripts exist in sense:antisense pairs including IGF2BP2, which may have a direct regulatory function in the context of colorectal cancer. While the functional relevance of the antisense transcripts has been established by many studies, their functional role is currently unclear; however, the numbers that have been detected by the disease-specific microarray would suggest that they may be important regulatory transcripts. This study has demonstrated the power of a disease-specific transcriptome-based approach and highlighted the potential novel biologically and clinically relevant information that is gained when using such a methodology.

The addition of cetuximab to oxaliplatin-based first-line combination chemotherapy for advanced colorectal cancer: results of the MRC COIN trial.

Background: In the Medical Research Council (MRC) COIN trial, the epidermal growth factor receptor (EGFR)-targeted antibody cetuximab was added to standard chemotherapy in first-line treatment of advanced colorectal cancer with the aim of assessing effect on overall survival.
Methods: In this randomised controlled trial, patients who were fit for but had not received previous chemotherapy for advanced colorectal cancer were randomly assigned to oxaliplatin and fluoropyrimidine chemotherapy (arm A), the same combination plus cetuximab (arm B), or intermittent chemotherapy (arm C). The choice of fluoropyrimidine therapy (capecitabine or infused fluouroracil plus leucovorin) was decided before randomisation. Randomisation was done centrally (via telephone) by the MRC Clinical Trials Unit using minimisation. Treatment allocation was not masked. The comparison of arms A and C is described in a companion paper. Here, we present the comparison of arm A and B, for which the primary outcome was overall survival in patients with KRAS wild-type tumours. Analysis was by intention to treat. Further analyses with respect to NRAS, BRAF, and EGFR status were done. The trial is registered, ISRCTN27286448.
Findings: 1630 patients were randomly assigned to treatment groups (815 to standard therapy and 815 to addition of cetuximab). Tumour samples from 1316 (81%) patients were used for somatic molecular analyses; 565 (43%) had KRAS mutations. In patients with KRAS wild-type tumours (arm A, n=367; arm B, n=362), overall survival did not differ between treatment groups (median survival 17·9 months [IQR 10·3—29·2] in the control group vs 17·0 months [9·4—30·1] in the cetuximab group; HR 1·04, 95% CI 0·87—1·23, p=0·67). Similarly, there was no effect on progression-free survival (8·6 months [IQR 5·0—12·5] in the control group vs 8·6 months [5·1—13·8] in the cetuximab group; HR 0·96, 0·82—1·12, p=0·60). Overall response rate increased from 57% (n=209) with chemotherapy alone to 64% (n=232) with addition of cetuximab (p=0·049). Grade 3 and higher skin and gastrointestinal toxic effects were increased with cetuximab (14 vs 114 and 67 vs 97 patients in the control group vs the cetuximab group with KRAS wild-type tumours, respectively). Overall survival differs by somatic mutation status irrespective of treatment received: BRAF mutant, 8·8 months (IQR 4·5—27·4); KRAS mutant, 14·4 months (8·5—24·0); all wild-type, 20·1 months (11·5—31·7).
Interpretation: This trial has not confirmed a benefit of addition of cetuximab to oxaliplatin-based chemotherapy in first-line treatment of patients with advanced colorectal cancer. Cetuximab increases response rate, with no evidence of benefit in progression-free or overall survival in KRAS wild-type patients or even in patients selected by additional mutational analysis of their tumours. The use of cetuximab in combination with oxaliplatin and capecitabine in first-line chemotherapy in patients with widespread metastases cannot be recommended.

Intermittent versus continuous oxaliplatin and fluoropyrimidine combination chemotherapy for first-line treatment of advanced colorectal cancer: results of the randomised phase 3 MRC COIN trial

Background: When cure is impossible, cancer treatment should focus on both length and quality of life. Maximisation of time without toxic effects could be one effective strategy to achieve both of these goals. The COIN trial assessed preplanned treatment holidays in advanced colorectal cancer to achieve this aim. Methods: COIN was a randomised controlled trial in patients with previously untreated advanced colorectal cancer. Patients received either continuous oxaliplatin and fluoropyrimidine combination (arm A), continuous chemotherapy plus cetuximab (arm B), or intermittent (arm C) chemotherapy. In arms A and B, treatment continued until development of progressive disease, cumulative toxic effects, or the patient chose to stop. In arm C, patients who had not progressed at their 12-week scan started a chemotherapy-free interval until evidence of disease progression, when the same treatment was restarted. Randomisation was done centrally (via telephone) by the MRC Clinical Trials Unit using minimisation. Treatment allocation was not masked. The comparison of arms A and B is described in a companion paper. Here, we compare arms A and C, with the primary objective of establishing whether overall survival on intermittent therapy was non-inferior to that on continuous therapy, with a predefined non-inferiority boundary of 1·162. Intention-to-treat (ITT) and per-protocol analyses were done. This trial is registered, ISRCTN27286448. Findings: 1630 patients were randomly assigned to treatment groups (815 to continuous and 815 to intermittent therapy). Median survival in the ITT population (n=815 in both groups) was 15·8 months (IQR 9·4—26·1) in arm A and 14·4 months (8·0—24·7) in arm C (hazard ratio [HR] 1·084, 80% CI 1·008—1·165). In the per-protocol population (arm A, n=467; arm C, n=511), median survival was 19·6 months (13·0—28·1) in arm A and 18·0 months (12·1—29·3) in arm C (HR 1·087, 0·986—1·198). The upper limits of CIs for HRs in both analyses were greater than the predefined non-inferiority boundary. Preplanned subgroup analyses in the per-protocol population showed that a raised baseline platelet count, defined as 400 000 per µL or higher (271 [28%] of 978 patients), was associated with poor survival with intermittent chemotherapy: the HR for comparison of arm C and arm A in patients with a normal platelet count was 0·96 (95% CI 0·80—1·15, p=0·66), versus 1·54 (1·17—2·03, p=0·0018) in patients with a raised platelet count (p=0·0027 for interaction). In the per-protocol population, more patients on continuous than on intermittent treatment had grade 3 or worse haematological toxic effects (72 [15%] vs 60 [12%]), whereas nausea and vomiting were more common on intermittent treatment (11 [2%] vs 43 [8%]). Grade 3 or worse peripheral neuropathy (126 [27%] vs 25 [5%]) and hand—foot syndrome (21 [4%] vs 15 [3%]) were more frequent on continuous than on intermittent treatment. Interpretation: Although this trial did not show non-inferiority of intermittent compared with continuous chemotherapy for advanced colorectal cancer in terms of overall survival, chemotherapy-free intervals remain a treatment option for some patients with advanced colorectal cancer, offering reduced time on chemotherapy, reduced cumulative toxic effects, and improved quality of life. Subgroup analyses suggest that patients with normal baseline platelet counts could gain the benefits of intermittent chemotherapy without detriment in survival, whereas those with raised baseline platelet counts have impaired survival and quality of life with intermittent chemotherapy and should not receive a treatment break.