Background: Colorectal cancer (CRC) is a leading cause of death worldwide. Despite its preventability through screening, compliance still needs to improve due to the invasiveness of current tools. There is a growing demand for validated molecular biomarker panels for minimally invasive blood-based CRC screening. This study assessed the diagnostic accuracy of four promising blood-based CRC biomarkers, individually and in combination. Methods: This case–control study involved plasma samples from 124 CRC cases and 124 age- and sex-matched controls. Biomarkers tested included methylated DNA encoding the Septin-9 gene (mSEPT9) using Epi proColon^® 2.0 CE, insulin-like growth factor binding protein 2 (IGFBP2), dickkopf-3 (DKK3), and pyruvate kinase M2 (PKM2) by ELISA. Diagnostic accuracy was measured using the receiver operating characteristic (ROC), area under the curve (AUC), as well as sensitivity and specificity. Results: Diagnostic accuracy for mSEPT9, IGFBP2, DKK3, and PKM2 was 62.9% (95% CI: 56.8–62.9%), 69.7% (95% CI: 63.1–69.7%), 61.6% (95% CI: 54.6–61.6%), and 50.8% (95% CI: 43.4–50.8%), respectively. The combined biomarkers yielded an AUC of 74.4% (95% CI: 68.1–80.6%), outperforming all biomarkers except IGFBP2. Conclusions: These biomarkers show potential for developing a minimally invasive CRC detection tool as an alternative to existing approaches, potentially increasing adherence, early detection, and survivorship.

: Dengue is the most common mosquito-borne viral disease in humans. Although many dengue virus (DENV) infections are asymptomatic or produce only mild illness, DENV can occasionally cause severe and fatal disease. In this study, we compared the severity of primary and secondary DENV-1 infections among patients enrolled in a prospective, hospital-based, acute febrile illnesses surveillance system in Puerto Rico (2012–2014). Serum samples collected <7 days after symptom onset were tested for DENV-serotypes by a real time-polymerase chain reaction assay. The positive samples that were collected ≤5 days after onset were then tested by a DENV IgG antibody ELISA to classify primary (IgG negative) and secondary (IgG positive) infections. Overall, 720 dengue infections (679 DENV-1, 3 DENV-2, and 38 DENV-4) were diagnosed during the study period. Of the 679 DENV-1 patients, 595 were included in the study, 445 (75%) were classified as secondary infections, and 150 (25%) as primary infections. Among these patients, 150 (25%) were classified as severe dengue. Severe dengue occurred in 28% of secondary DENV-1 infections. Severe disease was also common among primary DENV-1 infections, including 27% with plasma leakage, 15% with severe dengue, and 9% requiring admission to the intensive care unit. Even though DENV-1 has caused thousands of cases in Puerto Rico, this is the first report describing DENV-1 as the cause of severe primary infection in this country. Although secondary DENV-1 infections have an increased risk for severe disease, it is important for clinicians to be aware that any individual with dengue should be considered at risk for severe dengue.