Colonoscopy as a screening test for colorectal cancer in average-risk individuals

Electrochemical biosensors for measurement of colorectal cancer biomarkers

Colorectal cancer (CRC) is associated with one of the highest rates of mortality among cancers worldwide. The early detection and management of CRC is imperative. Biomarkers play an important role in CRC screening tests, CRC treatment, and prognosis and clinical management; thus rapid and sensitive detection of biomarkers is helpful for early detection of CRC. In recent years, electrochemical biosensors for detecting CRC biomarkers have been widely investigated. In this review, different electrochemical detection methods for CRC biomarkers including immunosensors, aptasensors, and genosensors are summarized. Further, representative examples are provided that demonstrate the advantages of electrochemical sensors modified by various nanomaterials. Finally, the limitations and prospects of biomarkers and electrochemical sensors in detection are also discussed. Graphical abstract.

KCNQ5 and C9orf50 Methylation in Stool DNA for Early Detection of Colorectal Cancer

Background

Aberrant DNA methylation has emerged as a class of promising biomarkers for early colorectal cancer (CRC) detection, but the performance of methylated C9orf50 and methylated KCNQ5 in stool DNA has never been evaluated.

Methods

Methylation specific quantitative PCR (qPCR) assays for methylated C9orf50 and methylated KCNQ5 were developed. The methylation levels of C9orf50 and KCNQ5 in 198 CRC patients, 20 advanced adenoma (AA) patients, 101 small polyp (SP) patients, and 141 no evidence of disease (NED) subjects were analyzed.

Results

The methylation levels of both KCNQ5 and C9orf50 genes were significantly higher in CRC and AA groups than those in SP and NED groups, but showed no significant difference among different stages of CRC. The sensitivities of methylated KCNQ5 and methylated C9orf50 for CRC detection were 77.3% (95% CI: 70.7–82.8%) and 85.9% (95% CI: 80.0–90.2%) with specificities of 91.5% (95% CI: 85.3–95.3%) and 95.0% (95% CI: 89.7–97.8%), respectively. When C9orf50 and methylated KCNQ5 were combined, the clinical performance for CRC detection was similar to that of methylated C9orf50 alone.

Conclusions

Stool DNA based methylated C9orf50 test has the potential to become an alternative approach for CRC screening and prevention.

A complex microsatellite at chromosome 7q33 as a new prognostic marker of colorectal cancer

Disease-specific markers are critical for early diagnosis, targeted therapy and prognostic prediction of diseases. Current study reports a complex microsatellite as a new prognostic marker of sporadic colorectal cancer. This microsatellite located at Chromosome 7q33 is composed of three tetranucleotide tandem repeats, (TTCC)₂(TCCC)₅(TCCT)₇, flanked by a CT-rich sequence. We analyzed polymorphisms of this microsatellite in 158 sporadic colorectal cancer, 143 matched normal adjacent tissues (NAT) and 150 health donors. Our results showed that this complex microsatellite was instable with polymorphic frequency of 77.2% in colorectal cancer, 52.4% in NAT and 54.7% in health donors (p<0.01) when compared to reference sequence. In the three tandem repeats, (TCCT)₇ site was most polymorphic accounting for over 70.0% of polymorphisms in this complex microsatellite, followed by (TTCC)₂ site for approximately 20%. Polymorphisms in (TCCC)₅ was rare. Polymorphisms at the (TCCT)₇ site were mainly insertions of 1 to 4 copies of TCCT (88.6%), and deletions occurred in about 6.4% of cases. The (TTCC)₂ site was featured with one copy TTCC insertions. Pair-wise analyses between colorectal tumors and NAT revealed that 88 of 121 (72.7%) tumors displayed expansion, contraction or both in these tetranucleotide tandem repeats when compared to NAT. A cross-analysis with clinicopathological data of 158 colorectal cancers revealed that polymorphic alterations of the microsatellite associated with less lymphatic metastasis (p<0.001), and the colorectal cancer patients with polymorphic changes in this microsatellite demonstrated better survival (n=112, p=0.0058). Together these data suggest that this complex microsatellite is a potential prognostic marker of sporadic colorectal cancer.

Translating colorectal cancer prevention through the guanylyl cyclase C signaling axis

Colorectal cancer (CRC) is a major public health concern, ranking among the leading causes of cancer death in both men and women. Because of this continued burden there is a clear need for improved treatment, and more importantly prevention of this disease. In recent years there is significant evidence to support the hypothesis that guanylyl cyclase C (GCY2C) is a tumor suppressor in the intestine, and that the loss of hormone ligands for this receptor is an important step in the disease process. Thus, ligand replacement therapy has been proposed as a strategy to prevent CRC. Until recently this strategy was not clinically plausible; however, the recent regulatory approval of linaclotide (LINZESS™, Forest Laboratories and Ironwood Pharmaceuticals, Inc.), an oral GUCY2C ligand, has raised the possibility of utilizing this strategy clinically to prevent CRC.

Does age or bilateral disease influence the value of hip arthroplasty?

BACKGROUND

Measuring value in medicine is an increasingly important issue as healthcare spending continues to rise and cost containment becomes even more important. However, value assessments can be affected by patient factors and comorbidities.

QUESTIONS/PURPOSES

We therefore quantified the approximate value of total hip arthroplasty and determined if patient age and Charnley classification affected the EuroQol5D (EQ5D) after hip arthroplasty.

METHODS

Using charge data and an institutional joint registry, we evaluated 1442 patients after hip arthroplasty. Using the Charnley case-mix index to define bilateral disease and age of 65 years to distinguish between elderly and young patients, statistical comparisons were made among all groups. We obtained subspecialty physician charges and hospital charges.

RESULTS

Patients with both unilateral and bilateral disease in both age groups had improved EQ5D scores after total hip arthroplasty, and the average change in scores was 0.27. There was no difference in the change in utility scores when patients older than 65 years of age were compared with patients younger than 65 years or when patients with unilateral disease were compared with those with bilateral disease. The average cost per quality-adjusted life-year (QALY) gained was $9773/QALY.

CONCLUSIONS

Our data suggest the value of total hip arthroplasty compares favorably with other medical and surgical interventions for other patient groups. No adjustments for patient age or disease status of the contralateral limb are necessary when reporting the value of total hip arthroplasty.

LEVEL OF EVIDENCE

Level IV, economic and decision analyses study. See Guidelines for Authors for a complete description of levels of evidence.