Microsatellite instability and loss of heterozygosity at chromosomal location 18q: prospective evaluation of biomarkers for stages II and III colon cancer--a study of CALGB 9581 and 89803

Pseudoprogression during treatment with pembrolizumab followed by rechallenge with chemotherapy in metastatic colorectal cancer: A case report

Disease progression during immunotherapy in colorectal cancer does not always indicate treatment failure. A case argues that carcinoembryonic antigen (CEA) may serve as an early marker to distinguish between pseudoprogression and real progression. Presentation of results from reintroduction of chemotherapy after progression on immunotherapy that suggest increased efficiency.

Is the Mirror Image Method Really Useful in Tumor Tissue Bank Quality Control?

Oncology research projects are highly dependent on the quality of tumor samples stored in the biobank. Microscopic control is important to ensure the quality of the frozen sample (Does the sample correspond to tumor tissue? Does the sample contain a sufficient number of tumor cells for molecular analysis?). The aim of this study was to evaluate the value of the mirror image method in quality control of colonic adenocarcinoma samples stored in a tumor bank. Microscopic concordance for the differentiation grade, malignant and normal cell percentages, necrosis, mucinous component, and ulceration was assessed on 82 colon adenocarcinoma banked samples and their paired, formalin-fixed, paraffin-embedded mirror controls. Molecular concordance for KRAS status was evaluated in 76 of these 82 cases. Morphological correspondence between frozen and mirror samples was good for the mucinous component (intraclass correlation coefficient [ICC] = 0.81), moderate for differentiation (Cohen's kappa coefficient [k] = 0.67), fair for malignant cells (ICC = 0.44), and poor for ulceration (k = 0.08), normal tissue (ICC = 0.36), and necrosis (ICC = 0.13) percentages. Molecular correspondence for KRAS status was almost perfect (95% correspondence, k = 0.88) between frozen and mirror samples. In conclusion, the mirror sample method is not a good alternative for microscopic and molecular control of frozen colonic adenocarcinoma samples.

Challenges and solutions in patient treatment strategies for stage II colon cancer

Colorectal cancer remains one of the most common cancers worldwide and, despite improvements in treatment options for late-stage metastatic cancer, there are still questions surrounding how best to treat early-stage disease patients. Some recent advances have been made in the staging of cancer and improving the risk assessment of strategies for patient treatment. A number of high-risk features have been proposed that may help to stratify stage II cancer patients into groups that will truly benefit from adjuvant chemotherapy. Diagnostic tests are becoming available to measure these biomarkers, utilizing both currently available and novel technologies. This review will describe the challenges in treatment decisions for early-stage colon cancer and how personalized medicine can assist clinicians in making the best treatment choices for patients with stage II colon cancer in particular.

Deficient mismatch repair as a prognostic marker in stage II colon cancer patients

BACKGROUND

A number of reports have evaluated the relationship between deficient DNA mismatch repair (dMMR) and colorectal cancer prognosis. Unfortunately, the exact prognostic role of dMMR has not been clearly established due to contradictory results. This study aims to determine the prognostic impact of dMRR in stage II colon cancer patients only. The appropriate identification of high-risk stage II colon cancers is of paramount importance in the selection of patients who may benefit from adjuvant treatment after surgery.

METHODS

Four hundred and fifty-two patients with curative resection of stage II colon cancer were included. Hospital records were used as data source, providing clinical, surgical, pathology, oncology and follow-up information for statistical analysis focusing on overall survival (OS) and time to progression (TTP). Mismatch repair status was determined by immunohistochemistry. Patient survival was followed-up for a mean of 77·35 months.

RESULTS

dMMR was detected in 93 of 452 patients (20·6%). No impact on overall survival (Log-Rank, p = 0·583, 95% CI 0·76-1·67). However, the hazard ratio 0·50 for TTP was highly significant (Log-Rank, p = 0·012, 95% CI 0·28-0·87) in patients with dMMR compared with those with mismatch repair proficient tumours (pMMR).

CONCLUSIONS

Patients with dMMR tumours have a lower risk for recurrence compared to those with pMMR tumours, but this finding did not correlate to better overall survival.

Study of histopathologic parameters to define the prognosis of stage II colon cancer

PURPOSE

Stage II colon cancer (CC) represents a challenging scenario for the choice of adjuvant chemotherapy; here, histologic factors need to be weighed up to establish the risk of recurrence. Tumor budding (TB) has recently been indicated as a confident predictor of clinical outcome in CC. Likewise, the presence of poorly differentiated clusters (PDCs) in a tumor has been pointed out as a leading criterion of a tumor grading system. Our aim was to evaluate in patients with stage II CC the relationship between these features and clinical outcome.

PATIENTS AND METHODS

The study included 174 cases of stage II CC; histopathologic parameters such as TB, PDCs, microsatellite instability (MSI), and CDX2 expression were analyzed.

RESULTS

There were 107 (70.9%), 32 (21.2%), and 12 (7.9%) TB scored 1, 2, and 3 respectively; 113 (72.9%), 30 (19.4%), and 12 (7.7%) tumors showed grade 1, 2, and 3 PDCs respectively. A high-MSI was detected in 32 cases (18.4%) while CDX2 was negative in 20 (11.5%) tumor samples. In the whole study population, only the TB was found to be associated with disease-specific survival (P = 0.01). No parameter apart from age (P = 0.04) was a significant prognostic factor for overall survival (P < 0.05). Other commonly reported variables, including tumor size, degree of tumor differentiation, lymphovascular invasion, number of lymph nodes harvested ≥ 12, MSI, and PDCs, were not shown to have significant results.

CONCLUSIONS

Although confirmatory studies are awaited, our work supports the role of the TB in defining risk groups of the stage II CC.

Validation of miRNA prognostic significance in stage II colorectal cancer: A protocol for systematic review and meta-analysis of observational clinical studies

BACKGROUND

Advances in early detection and treatment of colorectal cancer (CRC) has seen marked improvements in recent years. However, it is still the third leading cause of cancer-related deaths worldwide. Although there are studies reporting the significance of miRNAs in stage II colorectal cancer, there is no known comprehensive study utilising collective data from multiple published studies. Thus, this study will focus on performing a systematic review and meta-analysis using published data to identify and underline multiple miRNA targets, with regard to disease prognosis in stage II CRC patients.

METHODS

The systematic review will be reported according to the Preferred Reporting Items for Systematic Review and Meta-Analysis (PRISMA) guidelines, 2015 statement. The required articles will be obtained via a search of bibliographical databases such as Cochrane Library, EMBASE, MEDLINE, PubMed, and Web of Science. A set of keywords in multiple permutations will be used for the search. The reference lists of included studies will also be manually searched to further increase the robustness of the search results. The systematic review will primarily be done via a literary synthesis.

RESULTS

Quantitative data synthesis will be based on estimated effect across the studies with forest plots generated to observe pooled outcome measures. A fixed or random-effect model of meta-analysis will be used depending upon the heterogeneity observed between studies. Subgroup analysis will be carried out depending on the availability of sufficient clinical data.

CONCLUSION

Based on the systematic review and meta-analysis results of this study, the possible miRNAs could be predicted toward the prognosis of stage II colorectal cancer, and specific miRNAs may perhaps be considered as a biomarker and therapeutic target for this malignancy.

Microsatellite instability and manifestations of angiogenesis in stage IV of sporadic colorectal carcinoma

Angiogenesis represents one of the critical mechanisms that facilitates carcinoma development. The study objective was to evaluate whether the microsatellite instability of colorectal carcinoma has impact on the angiogenesis activity in liver metastases.In a cohort of 80 randomly selected patients with stage IV colorectal carcinoma, 30% were recognized as microsatellite unstable (Microsatellite instability high-frequency (MSI-H)). The endothelial progenitor cell fraction (CD309+) was counted within the subpopulation of CD34+CD45+ cell and CD34+CD45- cells by flow cytometer. vascular endothelial growth factor (VEGF) factor levels were quantified in serum samples by enzyme-linked immunosorbent assay (ELISA). A control group consisted of 36 healthy volunteers. The relationship of genomic instability to angiogenesis activity was evaluated by multivariate analysis in comparison to the controls, adopting a P < .05 value as statistically significant.The expression of endothelial progenitor cells (EPCs) and VEGF was significantly higher in MSI-H compared to both microsatellite stability (MSS) patients and healthy controls (P < .008). Multi-parametric analysis showed microsatellite instability (OR=9.12, P < .01), metastases in both lobes (OR = 32.83, P < .001) and simultaneous metastases outside liver (OR = 8.32, P < .01), as independent factors associated with increased angiogenesis as assessed by measures of EPC and VEGF. A higher percentage of EPCs within the white blood cell fraction (total % EPCs / white blood cells (WBC)) and higher serum concentrations of VEGF were present in patients with MSI-H colorectal cancer, and not with MSS cancers (P < .001).MSI-H patients with colorectal cancer metastases are associated with the overexpression of circulating EPCs and VEGF, potentially driving angiogenesis. This should be considered in therapeutic decision-making.

Precision Medicine Versus Population Medicine in Colon Cancer: From Prospects of Prevention, Adjuvant Chemotherapy, and Surveillance

With the advances of technologic revolution that provides new insights into human biology, genetics and cancer, as well as advantages of big data which amasses large amounts of information for us to approach cancer treatment and prevention, we are facing challenges of organically combining data from studies based on general population and information from individual testing and setting out precisional recommendations in cancer diagnosis, prevention, and treatment. We are obligated to accelerate the adaptation of new scientific discoveries into effective treatments and prevention for cancer. In this review, we introduce our opinions on bringing knowledge of precision and population medicine together to guide our clinical practice from the prospects of colorectal cancer prevention, stage III colon cancer adjuvant therapy, and postsurgery surveillance.

Influence of MSI and 18q LOH markers on capecitabine adjuvant monotherapy in colon cancer patients

PURPOSE

The aim of this study was to evaluate whether pretreatment analysis of selected molecular markers can be used for the prediction of disease-free survival (DFS)/overall survival (OS) of capecitabine adjuvant monotherapy in colon cancer patients.

PATIENTS AND METHODS

A total of 126 patients enrolled in a capecitabine Phase IV clinical trial were analyzed for microsatellite instability (MSI), 18q loss of heterozygosity (LOH), thymidylate synthase (TYMS) 5' variable number of tandem repeat (VNTR), and methylene tetrahydrofolate reductase (MTHFR) C677T variants. The significance in predicting 5-year DFS/OS was assessed by Kaplan-Meier and Cox regression analyses.

RESULTS

The MSI-high (MSI-H) genotype was significantly associated with DFS (HR 0.205, 95% CI 0.05-0.88, P=0.033) and OS (HR 0.208, 95% CI 0.05-0.89, P=0.035) compared to the microsatellite stable genotype. In models stratified according to clinicopathologic characteristics, the MSI-H genotype remained a positive predictive factor for DFS/OS only in patients with stage III (P=0.023) and patients with tumors localized proximally to the splenic flexure (P=0.004). Distal colon cancers with 18q LOH have a greater survival rate when treated with capecitabine than patients with stable tumors (81.3% vs 50.0%, HR for relapse 0.348, 95% CI 0.13-0.97, P=0.043). TYMS 5'VNTR and MTHFR C677T variants were not associated with DFS or OS.

CONCLUSION

MSI and 18q LOH markers have the potential to be utilized in the selection of colon cancer patients eligible for capecitabine adjuvant monotherapy.

Extent of enhancement on multiphase contrast-enhanced CT images is a potential prognostic factor of stage I-III colon cancer

OBJECTIVE

By evaluating extent of tumour enhancement on preoperative contrast-enhanced MDCT, we aimed to establish an imaging-based model to predict cancer-specific survival in stage I-III colon cancer.

METHODS

A total of 548 stage I-III colon cancer patients who underwent curative resection from 2007 to 2013 were retrospectively included and divided into primary cohort and validation cohort according to admission time. The attenuation coefficient of each colon cancer was measured on the workstation by drawing the ROI in CT images. The enhancement ratio was calculated using maximum tumour attenuation value in triphasic MDCT scanning divided by the minimum. Patients were divided into low/high-enhancement groups according to the optimal cut-off value derived from time-dependent ROC curve. Kaplan-Meier method and COX regression analysis were adopted to evaluate prognostic value of variables. A nomogram for prognosis was conducted on the basis of a multivariate Cox proportional hazard model.

RESULTS

No significant differences were observed in age, sex, pTNM stage, perioperative chemoradiotherapy, serum CEA, tumour size, tumour localisation and histologic type between low- and high-enhancement groups. The high-enhancement group had a significantly shorter cancer-specific survival rate (69.5%) than the low-enhancement group (85.9%) (p < 0.001). Subgroup analysis indicated that high-enhancement state was closely associated with increased risk of colon cancer mortality in stage I (p = 0.033), stage II (p = 0.002) and stage III (p = 0.014). Cox regression analysis indicated the extent of enhancement was an independent prognostic factor (HR 2.258, 95% CI 1.476-3.455; p < 0.001).

CONCLUSIONS

The extent of tumour enhancement on MDCT can serve as a potential risk factor for stage I-III colon cancer.

KEY POINTS

• Survival rates of stage I-III colon cancer vary widely even within the same stage. • Prognostic value of the extent of tumour enhancement on MDCT was assessed. • The high-enhancement group had a significantly shorter cancer-specific survival rate.

Should adjuvant chemotherapy be recommended to a 75-year-old woman with deficient mismatch repair (dMMR) gene product expression seen in a stage II colon adenocarcinoma with lymphovascular invasion?

The risk of recurrence from stage II colon cancer and benefit from adjuvant chemotherapy is influenced significantly by the molecular marker termed microsatellite instability and/or mismatch repair (MMR) gene product expression.¹ Study results and the National Comprehensive Cancer Network Colon Cancer Guideline panel suggest that adjuvant chemotherapy (fluoropyrimidine [5-FU] +/- oxaliplatin) be considered for patients with stage II colon adenocarcinoma harboring one or more "high-risk" features.² However, for patients with deficient-MMR (dMMR) stage II colon cancer, evidence suggests there may be a detrimental effect with adjuvant 5-FU alone.³ Finally, the addition of oxaliplatin to 5-FU does not appear to benefit older patients with stage II colon cancer.^4,5 For the patient described, the challenge involved how to advise an older patient with a dMMR stage II colon cancer and a high-risk feature. The identified lymphovascular invasion in the tumor implies that adjuvant chemotherapy with either 5-FU or capecitabine +/- oxaliplatin would be reasonable considerations. However, the dMMR status of the tumor suggests that 5-FU alone would be contraindicated, and her age suggests that a lack of benefit would be expected from oxaliplatin.

Noninferiority of three months versus six months of oxaliplatin-based adjuvant chemotherapy for resected colon cancer. How should IDEA findings affect clinical practice?

The eagerly awaited results of the multi-continental International Duration Evaluation of Adjuvant Chemotherapy (IDEA) project have recently been presented at major oncological meetings. The 3-year disease-free survival (DFS) was presented for 12,834 Stage III colon cancer patients in a pooled analysis of 6 individual noninferiority phase III randomized trials, all investigating three versus six months of oxaliplatin-based adjuvant therapy. Noninferiority (NI) could not be demonstrated for the whole population as the DFS hazard ratio (HR) of 1.07 with its 95% CI of 1.00-1.15 crossed the postulated NI boundary of 1.12. However, there was an expected reduction in the incidence of specific side effects with the three months treatment. NI could be demonstrated for the T3N1 subgroup (∼60% of patients, HR for DFS 1.01, 95% CI 0.90-1.12). Moreover, NI was also declared for the subgroup treated with the CAPOX regimen (capecitabine plus oxaliplatin, ∼40% of patients), but the CAPOX choice was physician-based and not subject to randomization. Overall, the IDEA results indicate that three months of therapy might be adequate for most of Stage III tumors; however, a small subset of these patients still have high risk of recurrence and death with short treatment duration. Precise predictors of benefit need to be identified, nonetheless tumor-intrinsic factors, such as tumor stage, might currently be considered as useful tools to inform the decision-making process.

Association of rs2282679 A>C polymorphism in vitamin D binding protein gene with colorectal cancer risk and survival: effect modification by dietary vitamin D intake

Background

The rs2282679 A>C polymorphism in the vitamin D binding protein gene is associated with lower circulating levels of vitamin D. We investigated associations of this SNP with colorectal cancer (CRC) risk and survival and whether the associations vary by dietary vitamin D intake and tumor molecular phenotype.

Methods

A population-based case-control study identified 637 incident CRC cases (including 489 participants with follow-up data on mortality end-points) and 489 matched controls. Germline DNA samples were genotyped with the Illumina Omni-Quad 1 Million chip in cases and the Affymetrix Axiom® myDesign™ Array in controls. Logistic regression examined the association between the rs2282679 polymorphism and CRC risk with inclusion of potential confounders. Kaplan-Meier curves and multivariable Cox models assessed the polymorphism relative to overall survival (OS) and disease-free survival (DFS).

Results

The rs2282679 polymorphism was not associated with overall CRC risk; there was evidence, however, of effect modification by total vitamin D intake (P_interaction = 0.019). Survival analyses showed that the C allele was correlated with poor DFS (per-allele HR, 1.36; 95%CI, 1.05–1.77). The association of rs2282679 on DFS was limited to BRAF wild-type tumors (HR, 1.58; 95%CI, 1.12–2.23). For OS, the C allele was associated with higher all-cause mortality among patients with higher levels of dietary vitamin D (HR, 2.11; 95%CI, 1.29–3.74), calcium (HR, 1.93; 95%CI, 1.08–3.46), milk (HR, 2.36; 95%CI, 1.26–4.44), and total dairy product intakes (HR, 2.03; 95%CI, 1.11–3.72).

Conclusion

The rs2282679 SNP was not associated with overall CRC risk, but may be associated with survival after cancer diagnosis. The association of this SNP on survival among CRC patients may differ according to dietary vitamin D and calcium intakes and according to tumor BRAF mutation status.

LRP1 expression in colon cancer predicts clinical outcome

LRP1 (low-density lipoprotein receptor-related protein 1), a multifunctional endocytic receptor, has recently been identified as a hub within a biomarker network for multi-cancer clinical outcome prediction. As its role in colon cancer has not yet been characterized, we here investigate the relationship between LRP1 and outcome.

MATERIALS AND METHODS

LRP1 mRNA expression was determined in colon adenocarcinoma and paired colon mucosa samples, as well as in stromal and tumor cells obtained after laser capture microdissection. Clinical potential was further investigated by immunohistochemistry in a population-based colon cancer series (n = 307). LRP1 methylation, mutation and miR-205 expression were evaluated and compared with LRP1 expression levels.

RESULTS

LRP1 mRNA levels were significantly lower in colon adenocarcinoma cells compared with colon mucosa and stromal cells obtained after laser capture microdissection. Low LRP1 immunohistochemical expression in adenocarcinomas was associated with higher age, right-sided tumor, loss of CDX2 expression, Annexin A10 expression, CIMP-H, MSI-H and BRAFV600E mutation. Low LRP1 expression correlated with poor clinical outcome, especially in stage IV patients. While LRP1 expression was downregulated by LRP1 mutation, LRP1 promoter was never methylated.

CONCLUSIONS

Loss of LRP1 expression is associated with worse colon cancer outcomes. Mechanistically, LRP1 mutation modulates LRP1 expression.

Combination of primary tumor location and mismatch repair status guides adjuvant chemotherapy in stage II colon cancer

Background

Current opinions on the benefits of adjuvant chemotherapy for stage II colon cancer are divided and reformative election of these patients is required. We examined whether the primary tumor location based on mismatch repair status and other risk factors could better inform the current guideline.

Materials and Methods

A total of 673 consecutive patients with stage II colon cancer were included in the analysis. Differences in the common clinicopathological factors between left-sided colon cancer and right-sided colon cancer were analyzed using Fisher's exact analysis. Kaplan-Meier analysis was used to distinguish the survival difference by primary tumor location and/or MMR status.

Results

RCC had a shorter overall survival (P = 0.001) and Disease-free survival (P = 0.050) than LCC but was associated with survival benefit from adjuvant chemotherapy (P = 0.001 and P = 0.011 for OS and DFS, respectively). Mismatch repair-proficient had a shorter OS (P = 0.036) and disease free survival (P = 0.034) than mismatch-repair deficient but chemotherapy improved the OS (P = 0.007). When the primary tumor location and MMR status were combined, the PMMR/RCC was the only subgroup that could benefit from adjuvant chemotherapy (P < 0.001 and P = 0.002 for OS and DFS, respectively). Other tumors such as DMMR/RCC, DMMR/LCC, and PMMR/LCC did not benefit.

Conclusions

The observed survival benefits in PMMR/RCC patients treated with adjuvant chemotherapy will allow better selection of patients for chemotherapy who are in stage II.

Adjuvant Chemotherapy for Stage II Colon Cancer: A Clinical Dilemma

The decision to treat a patient with stage II colon cancer with adjuvant chemotherapy can be challenging. Although the benefit of treatment is clear in most patients with stage III disease, the decision to provide chemotherapy after surgical resection in stage II disease must be made on an individual basis. Several trials have demonstrated the small but absolute benefits of receiving adjuvant chemotherapy for stage II colon cancer for disease-free survival and overall survival. In an attempt to better understand the role of chemotherapy, several studies were performed that identified high-risk characteristics that can be used prognostically and predictively to aid in the clinical decision making process. ASCO, the National Comprehensive Cancer Network, and the European Society of Medical Oncology have published guidelines describing these high-risk characteristics. Since then, several other molecular markers have emerged that may offer more information on a given patient's risk for recurrence. The decision to treat a patient with stage II colon cancer must be made on an individual basis, considering the risks and benefits of treatment. In this short review, we will present the available evidence and offer possible directions for future study.

Prognostic value of loss of heterozygosity and sub-cellular localization of SMAD4 varies with tumor stage in colorectal cancer

Background

Although loss of heterozygosity (LOH) at chromosome location 18q21 and decreased expression of SMAD4 in invasive colorectal cancers (CRCs) correlate with poor patient survival, the prognostic value of LOH at 18q21 and sub-cellular localization of SMAD4 have not been evaluated in relation to tumor stage.

Methods

Genomic DNA samples from 209 formalin-fixed, paraffin-embedded sporadic CRC tissues and their matching controls were analyzed for 18q21 LOH, and corresponding tissue sections were evaluated by immunohistochemistry for expression of SMAD4 and assessed for its sub-cellular localization (nuclear vs. cytoplasmic). In addition, 53 frozen CRCs and their matching control tissues were analyzed for their mutational status and mRNA expression of SMAD4. The phenotypic expression pattern and LOH status were evaluated for correlation with patient survival by the use of Kaplan-Meier and Cox regression models.

Results

LOH of 18q21 was detected in 61% of the informative cases. In 8% of the cases, missense point mutations were detected in Smad4. In CRCs, relative to controls, there was increased SMAD4 staining in the cytoplasm (74%) and decreased staining in the nuclei (37%). LOH of 18q21 and high cytoplasmic localization of SMAD4 were associated with shortened overall survival of Stage II patients, whereas low nuclear expression of SMAD4 was associated with worse survival, but only for patients with Stage III CRCs.

Conclusions

LOH of 18q21 and high cytoplasmic localization of SMAD4 in Stage II CRCs and low nuclear SMAD4 in Stage III CRCs are predictors of shortened patient survival.

Systematic immunohistochemical screening for mismatch repair and ERCC1 gene expression from colorectal cancers in China: Clinicopathological characteristics and effects on survival

BACKGROUND

We performed a systematic screening of colorectal cancer (CRC) tissues to investigate whether mismatch repair (MMR) status and ERCC1 protein expression could be predictive of clinical outcomes for these patients following the recommendation of The Evaluation of Genomic Applications in Practice of Prevention (EGAPP).

METHODS

The expression of four MMR genes and ERCC1 were assessed by immunohistochemistry (IHC) from cancer tissue samples of 2233 consecutive CRC patients.

RESULTS

We observed that most CRC patients with a proficient MMR (pMMR) status tended to have simultaneous ERCC1 protein expression (P< 0.001). Stage III CRC patients with deficient MMR (dMMR) had higher prognoses than the same stage patients with pMMR (DFS: 74% vs 65%, P = 0.04; OS: 79% vs 69%, P = 0.04). Here, dMMR is also associated with poorer survival for stage II patients after chemotherapy (DFS: 66% vs 78%, P = 0.04). Stage II and III patients that were shown to express ERCC1 protein had higher DFS and OS than those that were deficient in expression (stage II, DFS: 83% vs 70%, P = 0.006; OS 85% vs 73%, P = 0.02. Stage III, DFS: 67% vs56%, P = 0.03; OS: 71% vs 57%, P = 0.04).

CONCLUSIONS

Our results indicate that dMMR appeared to predictive of a survival benefit for stage III CRC patients. We also found the determination of ERCC1 expression to be useful for predicting DFS or OS for stage II and III CRC patients. In addition, the expression of MMR genes and ERCC1 showed a significant relationship.

Tumor location as a novel high risk parameter for stage II colorectal cancers

Current studies do not accurately evaluate the influence of tumor location on survival of colorectal cancer patients. This study aimed to explore whether tumor location could be identified as another high-risk factor in stage II colorectal cancer by using data identified from the Surveillance, Epidemiology, and End Results database. All colorectal cancer patients between 2004 and 2008 were grouped into three according to tumor location. Of 33,789 patients diagnosed with stage II colorectal cancer, 46.8% were right colon cancer, 37.5% were left colon cancer and 15.7% were rectal cancer. The 5-year cancer specific survivals were examined. Right colon cancer was associated with the female sex, older age (> 50), and having over 12 lymph nodes resected. Conversely, rectal cancer was associated with the male sex, patients younger than 50 years of age and insufficient lymph node resection. The characteristics of left colon cancer were between them and associated with Asian or Pacific Islander populations, T4 stage, and Grade II patients. The prognostic differences between three groups were significant and retained after stratification by T stage, histological grade, number of regional nodes dissected, age at diagnose, race and sex. Furthermore, the significant difference of location was retained as an independent high-risk parameter. Thus, stage II colorectal cancers of different locations have different clinic-pathological features and cancer-specific survivals, and tumor location should be recognized as another high-risk parameter in stage II colorectal cancer.

AQP9-induced cell cycle arrest is associated with RAS activation and improves chemotherapy treatment efficacy in colorectal cancer

Aquaporin-9 (AQP9) expression is associated with arsenic sensitivity in leukemia cells. However, the role of AQP9 in regulating tumor sensitivity to adjuvant chemotherapy in colorectal cancer (CRC) has not been elucidated. In this study, we demonstrated that AQP9 can serve as an independent predictive marker for adjuvant chemotherapy in CRC. Patients with high AQP9 expression had higher rate of disease-free survival (DFS) than those with low AQP9 expression. Upregulation of AQP9 was associated with enhanced chemosensitivity to 5-fluorouracil (5-FU) both in vitro and in vivo. Overexpression of AQP9 resulted in an increased intracellular level of 5-FU in CRC cells, hence leading to a higher percentage of apoptosis after 5-FU treatment. Moreover, AQP9 is positively associated with RAS activation and other downstream signaling molecules in CRC. AQP9 overexpression resulted in p21 upregulation and induced S-phase arrest. Taken together, AQP9 enhances the cytotoxic response to 5-FU in CRC cells by simultaneously inducing S-phase arrest via activation of RAS signaling and facilitating drug uptake. Our results suggest that AQP9 might be a novel predictor for the benefit of 5-FU-based chemotherapy in CRC. The identification of AQP9-induced tumor sensitivity to 5-FU highlights the role of AQP9 in regulating chemosensitivity in CRC.

CpG island methylator phenotype identifies high risk patients among microsatellite stable BRAF mutated colorectal cancers

The prognostic value of CpG island methylator phenotype (CIMP) in colorectal cancer remains unsettled. We aimed to assess the prognostic value of this phenotype analyzing a total of 1126 tumor samples obtained from two Norwegian consecutive colorectal cancer series. CIMP status was determined by analyzing the 5‐markers CAGNA1G, IGF2, NEUROG1, RUNX3 and SOCS1 by quantitative methylation specific PCR (qMSP). The effect of CIMP on time to recurrence (TTR) and overall survival (OS) were determined by uni‐ and multivariate analyses. Subgroup analyses were conducted according to MSI and BRAF mutation status, disease stage, and also age at time of diagnosis (<60, 60‐74, ≥75 years). Patients with CIMP positive tumors demonstrated significantly shorter TTR and worse OS compared to those with CIMP negative tumors (multivariate hazard ratio [95% CI] 1.86 [1.31‐2.63] and 1.89 [1.34‐2.65], respectively). In stratified analyses, CIMP tumors showed significantly worse outcome among patients with microsatellite stable (MSS, P < 0.001), and MSS BRAF mutated tumors (P < 0.001), a finding that persisted in patients with stage II, III or IV disease, and that remained significant in multivariate analysis (P < 0.01). Consistent results were found for all three age groups. To conclude, CIMP is significantly associated with inferior outcome for colorectal cancer patients, and can stratify the poor prognostic patients with MSS BRAF mutated tumors.

What's new?

As many as one‐fifth of colorectal cancers have a CpG island methylator phenotype (CIMP) involving widespread promoter DNA methylation. CIMP is associated with key factors related to disease outcome, including microsatellite instability and BRAF mutations. In this study, CIMP was found to be significantly associated with worse prognosis in colorectal cancer patients, particularly those with microsatellite stable (MSS) BRAF‐mutated tumors. In stratified analyses, trends toward worse survival were identified for CIMP‐positive stage III and stage IV patients in the MSS BRAF‐mutated group. The findings suggest that CIMP status should be included in prognostic analyses at time of diagnosis.

Exceptional Chemotherapy Response in Metastatic Colorectal Cancer Associated With Hyper-Indel-Hypermutated Cancer Genome and Comutation of POLD1 and MLH1

PURPOSE

A73-year-old woman with metastatic colon cancer experienced a complete response to chemotherapy with dose-intensified irinotecan that has been durable for 5 years. We sequenced her tumor and germ line DNA and looked for similar patterns in publicly available genomic data from patients with colorectal cancer.

PATIENTS AND METHODS

Tumor DNA was obtained from a biopsy before therapy, and germ line DNA was obtained from blood. Tumor and germline DNA were sequenced using a commercial panel with approximately 250 genes. Whole-genome amplification and exome sequencing were performed for POLE and POLD1. A POLD1 mutation was confirmed by Sanger sequencing. The somatic mutation and clinical annotation data files from the colon (n = 461) and rectal (n = 171) adenocarcinoma data sets were downloaded from The Cancer Genome Atlas data portal and analyzed for patterns of mutations and clinical outcomes in patients with POLE- and/or POLD1-mutated tumors.

RESULTS

The pattern of alterations included APC biallelic inactivation and microsatellite instability high (MSI-H) phenotype, with somatic inactivation of MLH1 and hypermutation (estimated mutation rate > 200 per megabase). The extremely high mutation rate led us to investigate additional mechanisms for hypermutation, including loss of function of POLE. POLE was unaltered, but a related gene not typically associated with somatic mutation in colon cancer, POLD1, had a somatic mutation c.2171G>A[p.Gly724Glu]. Additionally, we noted that the high mutation rate was largely composed of dinucleotide deletions. A similar pattern of hypermutation (dinucleotide deletions, POLD1 mutations, MSI-H) was found in tumors from The Cancer Genome Atlas.

CONCLUSION

POLD1 mutation with associated MSI-H and hyper-indel-hypermutated cancer genome characterizes a previously unrecognized variant of colon cancer that was found in this patient with an exceptional response to chemotherapy.

Neuroendocrine differentiation is predictive of poor survival in patients with stage II colorectal cancer

The diagnosis of neuroendocrine differentiation (NED) is made primarily on the basis of ultrastructure and/or immunohistochemistry (IHC). Synaptophysin (Syn) and chromogranin A (CgA) are two important frequently used NED markers in colorectal cancer (CRC). The association between NED and the prognosis of stage II CRC remains controversial. Administration of adjuvant chemotherapy remains challenging for stage II CRC. Identification of reliable factors that improve the selection of patients with stage II CRC at high risk following surgery is of great importance. A total of 151 cases of patients with stage II CRC who received radical surgery in The Second Affiliated Hospital of Zhejiang University (Hangzhou, China) between January 2002 and March 2011 were assayed for Syn and CgA using IHC, following which patients were classified as NED(+) or NED(-). Survival curves were constructed using the Kaplan-Meier estimator, and the prognostic value was determined using a log-rank test and Cox's regression test. In the 151 cases of stage II CRC examined, the incidence of NED was 34.44%. The overall survival of the NED(+) group was significantly less favorable than that of the NED(-) group (P=0.001). The 5-year survival rate was 68% for NED(+) (n=51) and 90% for NED(-) (n=97). The independent prognostic factors of survival of patients with stage II CRC following multivariate analysis were age ≥65 years (P=0.007) and NED-positivity (P=0.014). NED was revealed to be an independent factor of poor prognosis for patients with stage II CRC, which may offer potential for improved therapy stratification.

Cancer predisposition syndromes: lessons for truly precision medicine

Cancer predisposition syndromes are typically uncommon, monogenic, high-penetrance disorders. Despite their rarity, they have proven to be highly clinically relevant in directing cancer prevention strategies. As such, they share notable similarities with an expanding class of low-frequency somatic mutations that are associated with a striking prognostic or predictive effect in the tumours in which they occur. In this review, we highlight these commonalities, with particular reference to mutations in the proofreading domain of replicative DNA polymerases. These molecular phenotypes may occur as either germline or somatic events, and in the latter case, have been shown to confer a favourable prognosis and potential increased benefit from immune checkpoint inhibition. We note that incorporation of these variants into clinical management algorithms will help refine patient management, and that this will be further improved by the inclusion of other germline variants, such as those that determine the likelihood of benefit or toxicity from anti-neoplastic therapy. Finally, we propose that such integrated patient and tumour profiling will be essential if we are to deliver truly precision medicine for cancer patients, but in a similar way to rare germline mutations, we must ensure that we identify and utilize rare somatic mutations with strong predictive and prognostic effects. Copyright © 2016 Pathological Society of Great Britain and Ireland. Published by John Wiley & Sons, Ltd.

A Study of Thymidylate Synthase Expression as a Biomarker for Resectable Colon Cancer: Alliance (Cancer and Leukemia Group B) 9581 and 89803

Tumor thymidylate synthase (TS) levels were prospectively evaluated in two adjuvant therapy trials for patients with resected stage II or III colon cancer. Results indicated that high tumor TS levels were associated with improved disease‐free survival and overall survival following adjuvant therapy for colon cancer, although tumor TS expression did not predict benefit of 5‐fluorouracil‐based chemotherapy.

Purpose.

Tumor levels of thymidylate synthase (TS), a target of 5‐fluorouracil (5‐FU)‐based chemotherapy for colorectal cancer, have been studied as a predictive or prognostic biomarker with mixed results.

Patients and Methods.

Tumor TS levels were prospectively evaluated in two adjuvant therapy trials for patients with resected stage II or III colon cancer. TS expression was determined by standard immunohistochemistry and by automated quantitative analysis. Tumor mismatch repair deficiency (MMR‐D) and BRAF c.1799T > A (p.V600E) mutation status were also examined. Relationships between tumor TS, MMR‐D, and BRAF mutation status, overall survival (OS), and disease‐free survival (DFS) were investigated in the subset of stage III patients.

Results.

Patients whose tumors demonstrated high TS expression experienced better treatment outcomes, with DFS hazard ratio (HR) = 0.67, 95% confidence interval (CI) = 0.53, 0.84; and OS HR = 0.68, 95% CI = 0.53, 0.88, for high versus low TS expression, respectively. No significant interaction between TS expression and stage was observed (DFS: interaction HR = 0.94; OS: interaction HR = 0.94). Tumors with high TS expression were more likely to demonstrate MMR‐D (22.2% vs. 12.8%; p =  .0003). Patients whose tumors demonstrated both high TS and MMR‐D had a 7‐year DFS of 77%, compared with 58% for those whose tumors had low TS and were non‐MMR‐D (log‐rank p =  .0006). Tumor TS expression did not predict benefit of a particular therapeutic regimen.

Conclusion.

This large prospective analysis showed that high tumor TS levels were associated with improved DFS and OS following adjuvant therapy for colon cancer, although tumor TS expression did not predict benefit of 5‐FU‐based chemotherapy.

Implications for Practice.

This study finds that measurement of tumor levels of thymidylate synthase is not helpful in assigning specific adjuvant treatment for colorectal cancer. It also highlights the importance of using prospective analyses within treatment clinical trials as the optimal method of determining biomarker utility.

Role of Deficient Mismatch Repair in the Personalized Management of Colorectal Cancer

Colorectal cancer (CRC) represents the third most common type of cancer in developed countries and one of the leading causes of cancer deaths worldwide. Personalized management of CRC has gained increasing attention since there are large inter-individual variations in the prognosis and response to drugs used to treat CRC owing to molecular heterogeneity. Approximately 15% of CRCs are caused by deficient mismatch repair (dMMR) characterized by microsatellite instability (MSI) phenotype. The present review is aimed at highlighting the role of MMR status in informing prognosis and personalized treatment of CRC including adjuvant chemotherapy, targeted therapy, and immune checkpoint inhibitor therapy to guide the individualized therapy of CRC.

Exploring the Prognostic Role of Microsatellite Instability in Patients With Stage II Colorectal Cancer: A Systematic Review and Meta-Analysis

BACKGROUND

Many studies have disclosed the prognostic effect of microsatellite instability (MSI) and/or loss of mismatch repair proteins in colorectal cancer. Nevertheless, little evidence supports their role in the decision-making of adjuvant therapy for patients with stage II disease.

MATERIALS AND METHODS

The aim of this systematic review was to evaluate the prognostic and/or predictive role of MSI status in patients with stage II colorectal cancer on disease-free survival and overall survival. MEDLINE, EMBASE, and Cochrane libraries were searched to identify eligible studies.

RESULTS

Only 2 of 389 articles identified fulfilled the eligibility criteria. In both treated and untreated patients, high-level MSI improved disease-free survival compared with low-level MSI, suggesting a prognostic role but not supporting the hypothesis of a predictive effect of MSI.

CONCLUSIONS

Further studies are needed to explore the predictive role of MSI/mismatch repair proteins, because available data do not allow definitive conclusions.

Loss of Chromosome 8p Governs Tumor Progression and Drug Response by Altering Lipid Metabolism

Large-scale heterozygous deletions are a hallmark of cancer genomes. The concomitant loss of multiple genes creates vulnerabilities that are impossible to reveal through the study of individual genes. To delineate the functional outcome of chromosome 8p loss of heterozygosity (LOH), a common aberration in breast cancer, we modeled 8p LOH using TALEN-based genomic engineering. 8p LOH alters fatty acid and ceramide metabolism. The shift in lipid metabolism triggers invasiveness and confers tumor growth under stress conditions due to increased autophagy. The resistance of 8p-deleted cells to chemotherapeutic drugs concurs with poorer survival rates of breast cancer patients harboring an 8p LOH. The autophagy dependency of 8p-deleted cells provides the rational basis for treatment of 8p LOH tumors with autophagy inhibitors.

IGFBP-3 Gene Methylation in Primary Tumor Predicts Recurrence of Stage II Colorectal Cancers

OBJECTIVES

To evaluate the influence of IGFBP-3 methylation on recurrence in patients with stage II colorectal cancer (CRC) from 2 independent cohorts.

BACKGROUND

The relationship between IGFBP-3 methylation in primary tumors (PTs) or lymph nodes (LNs) and risk of recurrence in patients with stage II CRC treated with surgery alone is unknown.

METHODS

IGFBP-3 methylation of DNA from 115 PTs and 1641 LNs in patients with stage II CRC from 2 independent cohorts was analyzed. Forty patients developed recurrence, whereas 75 matched patients remained recurrence free for more than 2 years after surgery. Cox proportional hazard models were used to calculate hazard ratios (HRs) of recurrence, adjusted for patient and tumor characteristics.

RESULTS

Methylation of IGFBP-3 in PTs was identified to be significantly associated with risk of recurrence in the training set. The signature was tested in a validation set and classified 40.7% of patients as high risk. Five-year recurrence-free survival rates were 76.4% and 58.3% for low- and high-risk patients, respectively, with an HR of 2.21 (95% confidence interval, 1.04-4.68; P = 0.039). In multivariate analysis, the signature remained the most significant prognostic factor, with an HR of 2.40 (95% confidence interval, 1.10-5.25; P = 0.029). A combined analysis of 1641 LNs from the 2 sets identified IGFBP-3 methylation in LNs was not associated with risk of recurrence.

CONCLUSIONS

Detection of IGFBP-3 methylation in PTs, but not in LNs, provides a powerful tool for the identification of patients with stage II CRC at high risk of recurrence.

A panoply of errors: polymerase proofreading domain mutations in cancer

Although it has long been recognized that the exonucleolytic proofreading activity intrinsic to the replicative DNA polymerases Pol δ and Pol ε is essential for faithful replication of DNA, evidence that defective DNA polymerase proofreading contributes to human malignancy has been limited. However, recent studies have shown that germline mutations in the proofreading domains of Pol δ and Pol ε predispose to cancer, and that somatic Pol ε proofreading domain mutations occur in multiple sporadic tumours, where they underlie a phenotype of 'ultramutation' and favourable prognosis. In this Review, we summarize the current understanding of the mechanisms and consequences of polymerase proofreading domain mutations in human malignancies, and highlight the potential utility of these variants as novel cancer biomarkers and therapeutic targets.

Mouse models for the discovery of colorectal cancer driver genes

Colorectal cancer (CRC) constitutes a major public health problem as the third most commonly diagnosed and third most lethal malignancy worldwide. The prevalence and the physical accessibility to colorectal tumors have made CRC an ideal model for the study of tumor genetics. Early research efforts using patient derived CRC samples led to the discovery of several highly penetrant mutations (e.g., APC, KRAS, MMR genes) in both hereditary and sporadic CRC tumors. This knowledge has enabled researchers to develop genetically engineered and chemically induced tumor models of CRC, both of which have had a substantial impact on our understanding of the molecular basis of CRC. Despite these advances, the morbidity and mortality of CRC remains a cause for concern and highlight the need to uncover novel genetic drivers of CRC. This review focuses on mouse models of CRC with particular emphasis on a newly developed cancer gene discovery tool, the Sleeping Beauty transposon-based mutagenesis model of CRC.

Personalized treatment for patients with colorectal cancer: role of biomarkers

The systemic treatment of patients with colorectal cancer (CRC) has traditionally been based on clinical and tumor histological criteria. Recently however, several prognostic and predictive biomarkers have been proposed for patients with newly diagnosed CRC, including the subgroup with stage II disease. Among the best validated prognostic biomarkers for CRC are CEA levels, MS instability status and certain gene signatures. Although no biomarker currently exists for identifying patients likely to benefit from chemotherapy, the mutational status of KRAS and NRAS is used to predict response to cetuximab and panitumumab. For upfront identification of patients at high risk of suffering from severe therapy-related toxicity, specific variants of dihydropyrimidine dehydrogenase may be measured for predicting toxicity from fluoropyrimidines and uridine diphosphate glucuronosyltransferase*28 (UGT1A1*28) for predicting toxicity from irinotecan.

Prognostic factors in sporadic colon cancer with high-level microsatellite instability

BACKGROUND

The microsatellite instability-high (MSI-H) phenotype of colon cancer has a good prognosis and limited response to chemotherapy. We aimed to investigate prognostic factors and oncologic outcomes in patients with MSI-H sporadic colon cancer.

METHODS

A total of 329 patients with MSI-H sporadic colon cancer who underwent radical surgery from January 2004 to December 2012 at a single institution were included. We analyzed prognostic factors and oncologic outcomes according to chemotherapy in these patients compared with patients with MSI-low/microsatellite stable colon cancer.

RESULTS

Among the 329 patients, 174 were male and 155 were female. The median age was 59 years. The population consisted of 220 patients with stage II, 97 with stage III, and 12 with stage IV disease. Old age and advanced stage were independent poor prognostic factors of overall survival (OS; P = .014 and P = .040, respectively) and advanced stage and presence of perineural invasion were independent poor prognostic factors of disease-free survival (DFS; P = .004 and P = .001, respectively). In addition, a greater number of poor prognostic factors were associated with worse survival (P < .001). Patients with stage II disease showed no differences in OS and DFS according to receiving or not receiving chemotherapy (P = .140 and P = .694, respectively).

CONCLUSION

Old age, advanced stage, and presence of perineural invasion were independent and poor prognostic factors in patients with MSI-H sporadic colon cancer. Survival rates of MSI-H colon cancer patients with stage II disease were not improved by adjuvant chemotherapy.

In Vitro Adenosine Triphosphate-Based Chemotherapy Response Assay as a Predictor of Clinical Response to Fluorouracil-Based Adjuvant Chemotherapy in Stage II Colorectal Cancer

PURPOSE

We evaluated the usefulness of the in vitro adenosine triphosphate-based chemotherapy response assay (ATP-CRA) for prediction of clinical response to fluorouracil-based adjuvant chemotherapy in stage II colorectal cancer.

MATERIALS AND METHODS

Tumor specimens of 86 patients with pathologically confirmed stage II colorectal adenocarcinoma were tested for chemosensitivity to fluorouracil. Chemosensitivity was determined by cell death rate (CDR) of drug-exposed cells, calculated by comparing the intracellular ATP level with that of untreated controls.

RESULTS

Among the 86 enrolled patients who underwent radical surgery followed by fluorouracil-based adjuvant chemotherapy, recurrence was found in 11 patients (12.7%). The CDR ≥ 20% group was associated with better disease-free survival than the CDR < 20% group (89.4% vs. 70.1%, p=0.027). Multivariate analysis showed that CDR < 20% and T4 stage were poor prognostic factors for disease-free survival after fluorouracil-based adjuvant chemotherapy.

CONCLUSION

In stage II colorectal cancer, the in vitro ATP-CRA may be useful in identifying patients likely to benefit from fluorouracil-based adjuvant chemotherapy.

The Globalization of Cooperative Groups

The National Cancer Institute (NCI)-supported adult cooperative oncology research groups (now officially Network groups) have a longstanding history of participating in international collaborations throughout the world. Most frequently, the US-based cooperative groups work reciprocally with the Canadian national adult cancer clinical trial group, NCIC CTG (previously the National Cancer Institute of Canada Clinical Trials Group). Thus, Canada is the largest contributor to cooperative groups based in the United States, and vice versa. Although international collaborations have many benefits, they are most frequently utilized to enhance patient accrual to large phase III trials originating in the United States or Canada. Within the cooperative group setting, adequate attention has not been given to the study of cancers that are unique to countries outside the United States and Canada, such as those frequently associated with infections in Latin America, Asia, and Africa. Global collaborations are limited by a number of barriers, some of which are unique to the countries involved, while others are related to financial support and to US policies that restrict drug distribution outside the United States. This article serves to detail the cooperative group experience in international research and describe how international collaboration in cancer clinical trials is a promising and important area that requires greater consideration in the future.

ERCC1 and TS Expression as Prognostic and Predictive Biomarkers in Metastatic Colon Cancer

In patients with metastatic colon cancer, response to first line chemotherapy is a strong predictor of overall survival (OS). Currently, oncologists lack diagnostic tests to determine which chemotherapy regimen offers the greatest chance for response in an individual patient. Here we present the results of gene expression analysis for two genes, ERCC1 and TS, measured with the commercially available ResponseDX: Colon assay (Response Genetics, Los Angeles, CA) in 41 patients with de novo metastatic colon cancer diagnosed between July 2008 and August 2013 at the University of California, San Diego. In addition ERCC1 and TS expression levels as determined by RNAseq and survival data for patients in TCGA were downloaded from the TCGA data portal. We found that patients with low expression of ERCC1 (n = 33) had significantly longer median OS (36.0 vs. 10.1 mo, HR 0.29, 95% CI .095 to .84, log-rank p = 9.0x10^-6) and median time to treatment to failure (TTF) following first line chemotherapy (14.1 vs. 2.4 mo, HR 0.17, 95% CI 0.048 to 0.58, log-rank p = 5.3x10^-4) relative to those with high expression (n = 4). After accounting for the covariates age, sex, tumor grade and ECOG performance status in a Cox proportional hazard model the association of low ERCC1 with longer OS (HR 0.18, 95% CI 0.14 to 0.26, p = 0.0448) and TTF (HR 0.16, 95% CI 0.14 to 0.21, p = 0.0053) remained significant. Patients with low TS expression (n = 29) had significantly longer median OS (36.0 vs. 14.8 mo, HR 0.25, 95% CI 0.074 to 0.82, log-rank p = 0.022) relative to those with high expression (n = 12). The combined low expression of ERCC1/TS was predictive of response in patients treated with FOLFOX (40% vs. 91%, RR 2.3, Fisher’s exact test p = 0.03, n = 27), but not with FOLFIRI (71% vs. 71%, RR 1.0, Fisher’s exact test p = 1, n = 14). Overall, these findings suggest that measurement of ERCC1 and TS expression has potential clinical utility in managing patients with metastatic colorectal cancer.

MiR-320e is a novel prognostic biomarker in colorectal cancer

Background:

Advances in early detection and treatment have improved outcomes in patients with colorectal cancer (CRC). However, there remains a need for robust prognostic and predictive biomarkers. We conducted a systematic discovery and validation of microRNA (miRNA) biomarkers in two clinical trial cohorts of CRC patients.

Methods:

We performed an initial ‘discovery' phase using Affymetrix miRNA expression arrays to profile stage III CRC patients with and without tumour recurrence (n=50 per group) at 3-years of follow-up. All patients received adjuvant 5-fluorouracil (5-FU) plus oxaliplatin, that is, FOLFOX, treatment. During ‘validation', we analysed miRNAs using qRT–PCR in an independent cohort of 237 stage II–IV CRC patients treated with 5-FU-based chemotherapy, as well as in normal colonic mucosa from 20 healthy subjects. Association with disease recurrence, disease-free survival (DFS) and overall survival (OS) was examined using Cox proportional hazard models.

Results:

In the discovery cohort, miR-320e expression was significantly elevated in stage III colon cancers from patients with vs without recurrence (95% confidence interval (CI)=1.14–1.42; P<0.0001). These results were then independently validated in stage II and III tumours. Specifically, increased miR-320e expression was associated with poorer DFS (hazard ratio (HR)=1.65; 95% CI=1.27–2.13; P=0.0001) and OS (HR=1.78; 95% CI=1.31–2.41; P=0.0003) in stage III CRC patients.

Conclusions:

In two clinical trial cohorts, a systematic biomarker discovery and validation approach identified miR-320e to be a novel prognostic biomarker that is associated with adverse clinical outcome in stage III CRC patients treated with 5-FU-based adjuvant chemotherapy. These findings have important implications for the personalised management of CRC patients.

Deficient mismatch repair in colorectal cancer: current perspectives on patient management and future directions

Abstract 

Molecular aberrations leading to colorectal cancer are diverse and heterogeneity exists both at a molecular level and in clinical behavior. Defective mismatch repair (dMMR) is a feature of 15% of colorectal cancers. These are hypermutated tumors, mostly right sided and histopathologically elicit a marked immune response. A proportion of these arise due to germline mutation of a mismatch repair gene giving rise to Lynch syndrome, while the majority arise sporadically due to somatic alteration of the MLH1 mismatch repair gene. Although dMMR is associated with an excellent patient prognosis, as tumor stage advances the frequency of dMMR declines and the association with improved prognosis dissipates. It is apparent that dMMR tumors do not represent a unique molecular subset. As the knowledge of the underlying biology evolves, the hope is for individualized therapy that goes well beyond the crude and oversimplified categorization of dMMR versus proficient MMR.

Systematic review of the predictive effect of MSI status in colorectal cancer patients undergoing 5FU-based chemotherapy

BACKGROUND

We systematically reviewed the evidence for the interaction of microsatellite instability status (MSI) and treatment with 5FU in colorectal cancer to determine how well MSI status predicts health outcomes in patients undergoing 5FU-based chemotherapy.

METHODS

We conducted a search of four electronic databases through June 2013. We considered studies that included both colorectal cancer patients treated with 5FU-based chemotherapy and untreated patients with survival outcomes presented by MSI status.

RESULTS

We identified 16 studies for qualitative analysis (9,212 patients) with 14 studies eligible for meta-analysis. The microsatellite stable (MSS) group showed an effect of 5FU treatment on disease-free survival (HR of 0.62 [95% CI: 0.54, 0.71]) and overall survival (HR of 0.65 [95% CI: 0.54, 0.79]), indicating that MSS patients who received 5FU treatment had longer survival than MSS patients who were untreated. The effect of 5FU treatment was not statistically significant for microsatellite high (MSI-H) patients for disease-free survival (HR of 0.84 [95% CI: 0.53, 1.32]) or overall survival (HR 0.66 [95% CI: 0.43, 1.03]). However, the summarized point estimates of the effects of 5FU treatment for the MSS and MSI-H groups were not different at a statistically significant level.

CONCLUSIONS

Our analyses indicate that treatment with 5FU-based chemotherapy improves disease-free and overall survival in CRC patients, but that there is no difference in the effect of treatment based on MSI status. Therefore, the use of MSI status to guide treatment decisions about the use of 5FU treatment for CRC has no significant benefits for patients.

Prognosis of stage II and III colon cancer treated with adjuvant 5-fluorouracil or FOLFIRI in relation to microsatellite status: results of the PETACC-3 trial

BACKGROUND

Although colon cancer (CC) with microsatellite instability (MSI) has a more favorable prognosis than microsatellite stable (MSS) CC, the impact varies according to clinicopathological parameters. We studied how MSI status affects prognosis in a trial-based cohort of stage II and III CC patients treated with 5-fluorouracil (5-FU)/leucovorin or FOLFIRI.

MATERIALS AND METHODS

Tissue specimens of 1254 patients were tested for 10 different loci and were classified as MSI-high (MSI-H) when three or more loci were unstable and MSS otherwise. Study end points were overall survival (OS) and relapse-free survival (RFS).

RESULTS

In stage II, RFS and OS were better for patients with MSI-H than with MSS CC [hazard ratio (HR) 0.26, 95% CI 0.10-0.65, P = 0.004 and 0.16, 95% CI 0.04-0.64, P = 0.01). In stage III, RFS was slightly better for patients with MSI-H CC (HR 0.67, 95% CI 0.46-0.99, P = 0.04), but the difference was not statistically significant for OS (HR 0.70, 95% CI 0.44-1.09, P = 0.11). Outcomes for patients with MSI-H CC were not different between the two treatment arms. RFS was better for patients with MSI-H than with MSS CC in the right and left colon, whereas for OS this was significant only in the right colon. For patients with KRAS- and BRAF-mutated CC, but not for double wild-type patients, RFS and OS were significantly better when the tumors were also MSI-H. An interaction test was statistically significant for KRAS and MSI status (P = 0.005), but not for BRAF status (P = 0.14).

CONCLUSIONS

Our results confirm that for patients with stage II CC but less so for those with stage III MSI-H is strongly prognostic for RFS and OS. In the presence of 5-FU treatment, stage II patients with MSI-H tumors maintain their survival advantage in comparison with MSS patients and adding irinotecan has no added benefit. CLINICALTRIALS.GOV IDENTIFIER: NCT00026273.

Risk of recurrence in patients with colon cancer stage II and III: a systematic review and meta-analysis of recent literature

BACKGROUND

Adjuvant chemotherapy is established routine therapy for colon cancer (CC) patients with radically resected stage III and 'high-risk' stage II disease. The decision on recommending adjuvant chemotherapy, however, is based on data from older patient cohorts not reflecting improvements in pre-operative staging, surgery, and pathological examination. The aim is to review the current risk of recurrence in stage II and III patients and second, to estimate the relative importance of routinely assessed clinico-pathological variables.

METHODS

The PubMed/MEDLINE and the Cochrane databases were systematically searched for randomized controlled studies and observational studies published after 1 January 2005 with patients included after January 1995 on prognosis in surgically treated stage II and III CC patients.

RESULTS

Of 2596 studies identified, 37 met the inclusion criteria and 25 provided data for meta-analysis. The total patient sample size in the 25 studies reporting either disease-free (DFS) or recurrence-free survival was 15 559 in stage II and 18 425 in stage III. Five-year DFS for stage II patients operated without subsequent adjuvant chemotherapy was 81.4% [95% confidence interval (CI) 75.4-87.4; in studies with good/very good quality of reporting 82.7%, (95% CI 80.8-84.6)]. For stage II patients treated with adjuvant chemotherapy, the five-year DFS was 79.3% (95% CI 75.6-83.1). For stage III patients without chemotherapy, five-year DFS was 49.0% (95% CI 23.2-74.8) and for those treated with adjuvant chemotherapy, 63.6% (95% CI 59.3-67.9). The prognostic impact of commonly investigated clinico-pathological parameters, (pT-stage, pN-stage, differentiation, number of lymph nodes studied, MMR-status, and emergency surgery) were confirmed.

CONCLUSIONS

In this meta-analysis, studies with good quality of reporting show a five-year DFS of 82.7% for stage II CC without adjuvant chemotherapy, whereas the five-year DFS is 63.8% for stage III CC with adjuvant chemotherapy. Due to insufficient reporting on treatment quality the presented DFS is likely an under-estimation of what is achieved at high-quality centers today.

Prognostic significance of POLE proofreading mutations in endometrial cancer

BACKGROUND

Current risk stratification in endometrial cancer (EC) results in frequent over- and underuse of adjuvant therapy, and may be improved by novel biomarkers. We examined whether POLE proofreading mutations, recently reported in about 7% of ECs, predict prognosis.

METHODS

We performed targeted POLE sequencing in ECs from the PORTEC-1 and -2 trials (n = 788), and analyzed clinical outcome according to POLE status. We combined these results with those from three additional series (n = 628) by meta-analysis to generate multivariable-adjusted, pooled hazard ratios (HRs) for recurrence-free survival (RFS) and cancer-specific survival (CSS) of POLE-mutant ECs. All statistical tests were two-sided.

RESULTS

POLE mutations were detected in 48 of 788 (6.1%) ECs from PORTEC-1 and-2 and were associated with high tumor grade (P < .001). Women with POLE-mutant ECs had fewer recurrences (6.2% vs 14.1%) and EC deaths (2.3% vs 9.7%), though, in the total PORTEC cohort, differences in RFS and CSS were not statistically significant (multivariable-adjusted HR = 0.43, 95% CI = 0.13 to 1.37, P = .15; HR = 0.19, 95% CI = 0.03 to 1.44, P = .11 respectively). However, of 109 grade 3 tumors, 0 of 15 POLE-mutant ECs recurred, compared with 29 of 94 (30.9%) POLE wild-type cancers; reflected in statistically significantly greater RFS (multivariable-adjusted HR = 0.11, 95% CI = 0.001 to 0.84, P = .03). In the additional series, there were no EC-related events in any of 33 POLE-mutant ECs, resulting in a multivariable-adjusted, pooled HR of 0.33 for RFS (95% CI = 0.12 to 0.91, P = .03) and 0.26 for CSS (95% CI = 0.06 to 1.08, P = .06).

CONCLUSION

POLE proofreading mutations predict favorable EC prognosis, independently of other clinicopathological variables, with the greatest effect seen in high-grade tumors. This novel biomarker may help to reduce overtreatment in EC.

Determinants of recurrence after intended curative resection for colorectal cancer

Despite intended curative resection, colorectal cancer will recur in ∼45% of the patients. Results of meta-analyses conclude that frequent follow-up does not lead to early detection of recurrence, but improves overall survival. The present literature shows that several factors play important roles in development of recurrence. It is well established that emergency surgery is a major determinant of recurrence. Moreover, anastomotic leakages, postoperative bacterial infections, and blood transfusions increase the recurrence rates although the exact mechanisms still remain obscure. From pathology studies it has been shown that tumors behave differently depending on their location and recur more often when micrometastases are present in lymph nodes and around vessels and nerves. K-ras mutations, microsatellite instability, and mismatch repair genes have also been shown to be important in relation with recurrences, and tumors appear to have different mutations depending on their location. Patients with stage II or III disease are often treated with adjuvant chemotherapy despite the fact that the treatments are far from efficient among all patients, who are at risk of recurrence. Studies are now being presented identifying subgroups, in which the therapy is inefficient. Unfortunately, only few of these facts are implemented in the present follow-up programs. Therefore, further research is urgently needed to verify which of the well-known parameters as well as new parameters that must be added to the current follow-up programs to identify patients at risk of recurrence.

MRE11-deficiency associated with improved long-term disease free survival and overall survival in a subset of stage III colon cancer patients in randomized CALGB 89803 trial

Purpose

Colon cancers deficient in mismatch repair (MMR) may exhibit diminished expression of the DNA repair gene, MRE11, as a consequence of contraction of a T₁₁ mononucleotide tract. This study investigated MRE11 status and its association with prognosis, survival and drug response in patients with stage III colon cancer.

Patients and Methods

Cancer and Leukemia Group B 89803 (Alliance) randomly assigned 1,264 patients with stage III colon cancer to postoperative weekly adjuvant bolus 5-fluorouracil/leucovorin (FU/LV) or irinotecan+FU/LV (IFL), with 8 year follow-up. Tumors from these patients were analyzed to determine stability of a T₁₁ tract in the MRE11 gene. The primary endpoint was overall survival (OS), and a secondary endpoint was disease-free survival (DFS). Non-proportional hazards were addressed using time-dependent covariates in Cox analyses.

Results

Of 625 tumor cases examined, 70 (11.2%) exhibited contraction at the T₁₁ tract in one or both MRE11 alleles and were thus predicted to be deficient in MRE11 (dMRE11). In pooled treatment analyses, dMRE11 patients showed initially reduced DFS and OS but improved long-term DFS and OS compared with patients with an intact MRE11 T₁₁ tract. In the subgroup of dMRE11 patients treated with IFL, an unexplained early increase in mortality but better long-term DFS than IFL-treated pMRE11 patients was observed.

Conclusions

Analysis of this relatively small number of patients and events showed that the dMRE11 marker predicts better prognosis independent of treatment in the long-term. In subgroup analyses, dMRE11 patients treated with irinotecan exhibited unexplained short-term mortality. MRE11 status is readily assayed and may therefore prove to be a useful prognostic marker, provided that the results reported here for a relatively small number of patients can be generalized in independent analyses of larger numbers of samples.

Trial Registration

ClinicalTrials.gov NCT00003835